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Objective To assess the risk of birth defects in infants born after assisted human reproduction (AHR). Design Retrospective cohort study. Setting Niday Perinatal Database for the province of Ontario, 82 sites, both primary and tertiary centers. Patient(s) In 2005, information about reproductive assistance was reported for 61,569 deliveries. Intervention(s) The prevalence of birth defects diagnosed in the prenatal period or at birth was estimated for all types of AHR together and then by type of procedure. Main Outcome Measure(s) The excess risks of birth defects by AHR were calculated by unconditional logistic regressions using spontaneously conceived pregnancies as the reference and were expressed by odds ratio and 95% confidence intervals and adjusted for maternal age, smoking, infant gender, gestation, and parity. Result(s) The prevalence of birth defects with AHR procedures was 2.91%, which was 1.55-fold higher (95% confidence interval [CI], 1.03–2.38) than in the non-AHR population (1.86%). Specific anomalies that increased with AHR were gastrointestinal (odds ratio [OR], 9.85; 95% CI, 3.44–28.44), cardiovascular (OR, 2.30; 95% CI, 1.11–4.77), and musculoskeletal defects (OR, 1.54; 95% CI, 0.48–4.94). The risks of birth defects by types of AHR were 2.35% for ovulation induction, 2.89% for IUI, and 3.45% for IVF. Conclusion(s) There is a significant increased risk of birth defects associated with AHR, and the risk is higher in IVF and IUI. The potential risk of anomalies associated with AHR may be considered in the counseling that is offered to infertile couples.

Objective To ascertain differences in pregnancy outcomes between women with diabetes subtypes (type 1 [DM1], type 2 [DM2], women with gestational [GDM])] and non-diabetic women within a large Canadian population. Methods We performed a retrospective multi-cohort analysis of all obstetrical deliveries that occurred in the province of Ontario between April 1, 2005, and March 31, 2006. Data were extracted from the Ontario Niday Perinatal Database. Results Increased rates of major negative maternal and perinatal outcomes (i.e. preterm delivery, Caesarean section, pregnancy-induced hypertension/preeclampsia) occurred in women with DM1. Both DM1 and GDM subtypes were associated with the greatest risk of macrosomia, shoulder dystocia, and congenital anomalies. DM2 did not demonstrate an association with an increased risk of congenital malformations and stillbirth. Conclusion Diabetes in pregnancy, irrespective of subtype, predisposes women to poorer outcomes than those of the general obstetric population. However, this large population analysis is consistent with previous studies in showing that the adversity remains greatest for women with type 1 diabetes.

Objective Maternal mortality ratio (MMR) in Shanghai residents has been declining in the past two decades and has reached levels comparable to developed countries. The MMR in migrating population in Shanghai remains high, however. The objectives of this study were to compare the trends of MMR between residents and migrating population in Shanghai from 1996 to 2005 and to explore the reasons for the dramatic differences in MMR between the two groups living in the same city. Design Retrospective cohort study. Setting Shanghai, China. Population A total of 902 807 pregnancies with live births in Shanghai in the period of 1996–2005. Methods We first compared the overall MMR between migrating population and permanent residents in Shanghai and examined temporal trends of MMR in the two subpopulations. We then compared the causes and maternal characteristics of maternal deaths between the two subpopulations. Main outcome measures Maternal mortality and cause of death. Results A total of 902 807 live births and 243 maternal deaths were recorded in Shanghai in the period of 1996 to 2005, with an average MMR of 26.66 per 100 000 live births. The MMR in Shanghai residents declined dramatically from 22.47 per 100 000 in 1996 to 1.64 per 100 000 live births in 2005 (P 0.05). The main causes of maternal deaths in migrating population were postpartum haemorrhage (39.9%), pregnancy-induced hypertension (9.8%), and puerperal infection (9.3%), whereas the main causes of maternal death of Shanghai residents were chronic heart and liver diseases (20.0%), postpartum haemorrhage (12.9%), and amniotic fluid embolism (12.9%). Among the maternal death cases in migrating women, 60% had elementary education or less, 22% were unemployed, 65% had no prenatal visit, 44% gave a birth at home, and 12% of the deaths occurred at home. Conclusion Lack of access to quality maternity care, especially for the effective management of postpartum haemorrhage, is the main reason for the high MMR in migrating population in Shanghai.

Background: In previous studies, maternal exposure to folic acid antagonists was associated with increased risks of neural tube defects, cardiovascular defects, oral clefts and urinary tract defects. The objective of the current study was to assess the possible effects of using folic acid antagonists in pregnancy on placenta-mediated adverse outcomes of pregnancy. Methods: We used data from an administrative database to retrospectively compare the occurrence of placenta-mediated adverse pregnancy outcomes between pregnant women exposed to folic acid antagonists and women without exposure to these agents. Results: We included in the analysis a total of 14 982 women who had been exposed to folic acid antagonists and 59 825 women who had not been exposed. Sulfamethoxazole–trimethoprim was the most frequently prescribed dihydrofolate reductase inhibitor (a total of 12 546 exposures during the preconception period and all 3 trimesters), and phenobarbital was the most frequently prescribed among the other folic acid antagonists (a total of 1565 exposures). The risks of preeclampsia (adjusted odds ratio [OR] 1.52, 95% confidence interval [CI] 1.39–1.66), severe preeclampsia (OR 1.77, 95% CI 1.38–2.28), placental abruption (OR 1.32, 95% CI 1.12–1.57), fetal growth restriction defined as less than the 10th percentile (OR 1.07, 95% CI 1.01–1.13), fetal growth restriction defined as less than the 3rd percentile (OR 1.22, 95% CI 1.11–1.34) and fetal death (OR 1.35, 95% CI 1.07–1.70) were greater among mothers with exposure to folic acid antagonists. In general, the risks associated with exposure to other folic acid antagonists were higher than those associated with exposure to dihydrofolate reductase inhibitors. Supplementary analyses involving tight matching with propensity score, restriction of the analysis to women with exposure during the first and second trimesters and restriction of the analysis to specific categories of folic acid antagonists yielded similar results. Interpretation: Maternal exposure to folic acid antagonists appears to increase the risk of placenta-mediated adverse outcomes of pregnancy.

We examined the impact of the presence of one anomalous fetus in a twin pregnancy on perinatal outcomes in the normal cotwin. Perinatal outcomes in cotwins with an anomalous twin and cotwins without an anomalous twin were compared using data from the 1995 to 1997 United States Matched Multiple Births dataset. The two groups were matched by maternal age, parity, birth order, gender, and sex concordance (1:4 matching). The risks of preterm birth, low birth weight, small-for-gestational-age birth, fetal distress, the use of assisted ventilation, low Apgar score, fetal death, neonatal death, and infant death in the 3307 normal cotwins with a twin affected by structural anomalies were significantly higher than those of the 12,813 matched cotwins without an anomalous twin. The presence of one structurally anomalous fetus in a twin pregnancy increases the risks of adverse perinatal outcomes in the cotwin without a fetal anomaly.

This review summarizes the level of epidemiologic evidence for relationships between prenatal and/or early life exposure to environmental chemical contaminants and fetal, child, and adult health. Discussion focuses on fetal loss, intrauterine growth restriction, preterm birth, birth defects, respiratory and other childhood diseases, neuropsychological deficits, premature or delayed sexual maturation, and certain adult cancers linked to fetal or childhood exposures. Environmental exposures considered here include chemical toxicants in air, water, soil/house dust and foods (including human breast milk), and consumer products. Reports reviewed here included original epidemiologic studies (with at least basic descriptions of methods and results), literature reviews, expert group reports, meta-analyses, and pooled analyses. Levels of evidence for causal relationships were categorized as sufficient, limited, or inadequate according to predefined criteria. There was sufficient epidemiological evidence for causal relationships between several adverse pregnancy or child health outcomes and prenatal or childhood exposure to environmental chemical contaminants. These included prenatal high-level methylmercury (CH(3)Hg) exposure (delayed developmental milestones and cognitive, motor, auditory, and visual deficits), high-level prenatal exposure to polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), and related toxicants (neonatal tooth abnormalities, cognitive and motor deficits), maternal active smoking (delayed conception, preterm birth, fetal growth deficit [FGD] and sudden infant death syndrome [SIDS]) and prenatal environmental tobacco smoke (ETS) exposure (preterm birth), low-level childhood lead exposure (cognitive deficits and renal tubular damage), high-level childhood CH(3)Hg exposure (visual deficits), high-level childhood exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (chloracne), childhood ETS exposure (SIDS, new-onset asthma, increased asthma severity, lung and middle ear infections, and adult breast and lung cancer), childhood exposure to biomass smoke (lung infections), and childhood exposure to outdoor air pollutants (increased asthma severity). Evidence for some proven relationships came from investigation of relatively small numbers of children with high-dose prenatal or early childhood exposures, e.g., CH(3)Hg poisoning episodes in Japan and Iraq. In contrast, consensus on a causal relationship between incident asthma and ETS exposure came only recently after many studies and prolonged debate. There were many relationships supported by limited epidemiologic evidence, ranging from several studies with fairly consistent findings and evidence of dose-response relationships to those where 20 or more studies provided inconsistent or otherwise less than convincing evidence of an association. The latter included childhood cancer and parental or childhood exposures to pesticides. In most cases, relationships supported by inadequate epidemiologic evidence reflect scarcity of evidence as opposed to strong evidence of no effect. This summary points to three main needs: (1) Where relationships between child health and environmental exposures are supported by sufficient evidence of causal relationships, there is a need for (a) policies and programs to minimize population exposures and (b) population-based biomonitoring to track exposure levels, i.e., through ongoing or periodic surveys with measurements of contaminant levels in blood, urine and other samples. (2) For relationships supported by limited evidence, there is a need for targeted research and policy options ranging from ongoing evaluation of evidence to proactive actions. (3) There is a great need for population-based, multidisciplinary and collaborative research on the many relationships supported by inadequate evidence, as these represent major knowledge gaps. Expert groups faced with evaluating epidemiologic evidence of potential causal relationships repeatedly encounter problems in summarizing the available data. A major driver for undertaking such summaries is the need to compensate for the limited sample sizes of individual epidemiologic studies. Sample size limitations are major obstacles to exploration of prenatal, paternal, and childhood exposures during specific time windows, exposure intensity, exposure-exposure or exposure-gene interactions, and relatively rare health outcomes such as childhood cancer. Such research needs call for investments in research infrastructure, including human resources and methods development (standardized protocols, biomarker research, validated exposure metrics, reference analytic laboratories). These are needed to generate research findings that can be compared and subjected to pooled analyses aimed at knowledge synthesis.

Objective To assess the effects of pregnancy-induced hypertension on infant mortality in triplets stratified by gestational age at birth. Methods A retrospective cohort study was conducted using the linked 1995–2000 US birth/infant death database. Generalized estimating equations were used to evaluate the observed association. Results Pregnancy-induced hypertension was associated with lesser neonatal mortality (odds ration [OR]: 0.34, 95% CI: 0.21, 0.54), postneonatal mortality (OR: 0.54, 95% CI: 0.30, 0.99) and infant mortality (OR, 0.37, 95% CI: 0.25, 0.55) in triplets. It was also associated with a decreased risk of neonatal death (OR, 0.38; 95% CI, 0.21–0.67), postneonatal death (OR, 0.45; 95% CI, 0.21–0.97), and infant death (OR, 0.39; 95% CI, 0.24–0.64) in early preterm triplets, whereas the association was not significant in late preterm or in full-term triplets. Conclusion Pregnancy-induced hypertension is associated with a decreased risk of infant mortality in triplets. This effect varies with gestational age at birth.

Lopinavir/ritonavir (LPV/r) is the first ritonavir-boosted protease-inhibitor used in second-line anti-retroviral treatment (ART) in resource-limited regions. To evaluate the efficacy and safety outcomes of LPV/r in treatment-naïve and -experienced HIV-infected adults and pregnant women, we performed a meta-analysis of randomized controlled trials. Ten cohorts from 8 articles involving 2,584 ART-naïve patients, 5 cohorts from 4 articles involving 1,124 ART-experienced patients and 8 cohorts from 7 articles involving 2,191 pregnant women were selected for the meta-analyses. For ART-naïve patients, the virologic response rate (72.3%) of LPV/r combined with tenofovir (TDF) plus lamivudine/emtricitabine (3TC/FTC) arms was significantly greater than that of LPV/r plus non-TDF-FTC arms (65.5%, p = 0.047). For ART-experienced patients, the use of LPV/r revealed a 55.7% probability of virologic success. The incidence of abnormal total cholesterol (6.9%) for ART-experienced patients was significantly lower than that for ART-naïve patients (13.1%, p < 0.001). The use of LPV/r in pregnant women revealed a mother-to-child transmission (MTCT) rate of 1.1%, preterm birth rate of 13.2% and low birth weight rate of 16.2%. Our meta-analysis indicated that LPV/r was an efficacious regimen for ART-naïve patients and was more tolerable for ART-experienced patients. LPV/r also displayed a significant effect in preventing MTCT.

This study sought to assess the relationship between intertwin delivery interval (ITDI) and metabolic acidosis in the second twin at birth using a retrospective twin delivery cohort from a tertiary-level teaching hospital. Twin births were identified from an obstetrical database during a 10-year period from 1994 to 2004. Mean arterial cord pH and base deficit among different ITDIs were compared by analysis of variance. Logistic regression models were used to estimate effects of ITDI on metabolic acidosis. The incidence of metabolic acidosis in the second twin was defined as pH7.0, and base deficit was defined asor= 12 mmol/L at birth. After excluding those pregnancies with both twins delivered by cesarean section, birthweight less than 750 g of either twin, antepartum death of either twin, or second twins with missing cord arterial pH, we had 310 twin pairs left for final analysis. Mean pH was significantly lower and base deficit significantly higher for second twin after ITDI exceeded 60 minutes. The incidence of metabolic acidosis increased with increasing ITDI (chi2 test for linear trend, P = 0.02) and the risk of metabolic acidosis (odds ratio, 22.6; 95% confidence interval, 2.5 to 494.1) was increased in the second twins with ITDI longer than 60 minutes compared with those with ITDI less than 15 minutes. The incidence of metabolic acidosis increases with increasing ITDI and there is a statistically significant increased risk of neonatal acidosis after longer than 60 minutes compared with less than 15 minutes of ITDI.

We assess the impacts of operative delivery for the first twins with vertex presentation on neonatal outcomes in second twins using the 1995 to 1997 twin registry data of the United States. A total of 102,554 eligible twin pairs with vertex presentation for the first twin were included in the analysis. Of these, 50,748 (49.5%) first twins had a normal vaginal delivery, 43,504 (42.4%) were delivered by cesarean section, and 8302 (8.1%) were delivered by vaginal operation (vacuum extraction or forceps). In term twins, the risks of asphyxia-related mortality (odds ratio [OR], 3.08; 95% CI, 1.07 to 8.45), newborn injury (OR, 2.10; 95% 1.39 to 3.12), low Apgar score at 5 minutes (OR, 1.49; 95% 1.24 to 1.78), and mechanical ventilation use (OR, 1.34; 95% 1.20 to 1.51) were increased in the second twins whose co-twins were delivered by vaginal operation compared with those whose co-twins who had normal vaginal delivery. In contrast, the risks of asphyxia-related mortality (OR, 0.55; 95% 0.17 to 1.57), newborn injury (OR, 0.20; 95% 0.11 to 0.34), low Apgar score at 5 minutes (OR, 0.51; 95% 0.44 to 0.60), and mechanical ventilation use (OR, 0.77; 95% 0.71 to 0.83) were decreased in the second twins whose co-twins were delivered by cesarean section compared with those whose co-twins had a normal vaginal delivery. In conclusion, vaginal operative delivery for the first twins is related to the adverse neonatal outcomes of their co-twins, whereas cesarean delivery for the first twins is associated with the beneficial neonatal outcomes of their co-twins.

Objective To assess the association between pregnancy-induced hypertension (PIH) and infant mortality. Design Retrospective cohort study. Setting Birth and infant death registration dataset of the USA. Population A total of 17 432 987 eligible, liveborn singleton births in 1995–2000. Methods Multivariate logistic regression was applied to evaluate the association between PIH and infant mortality, with adjustment of potential confounders. Main outcome measures Infant death (0–364 days) and its three components: early neonatal death (0–6 days), late neonatal death (7–27 days), and postneonatal death (28–364 days). Results There was a significant reduction in infant mortality associated with PIH in early preterm infants (OR = 0.59, 95% CI: 0.56–0.63) and in late preterm infants (OR = 0.80, 95% CI: 0.73–0.87), but a significant increase in term infants (OR = 1.08, 95% CI: 1.02–1.14). Both in early preterm and late preterm births, early neonatal mortality (OR = 0.38, 95% CI: 0.34–0.42; OR = 0.68, 95% CI: 0.61–0.77) and late neonatal mortality (OR = 0.59, 95% CI: 0.50–0.70; OR = 0.76, 95% CI: 0.61–0.96) were decreased in infants born to mothers with PIH compared with those born to mothers with normal blood pressure. The PIH-associated reduction in neonatal mortality among preterm singletons was stronger in small-for-gestational-age infants than in normal growth infants and stronger in infants born to nulliparous women than in those born to multiparous women. Conclusions PIH is associated with lower risk of infant death in preterm births but higher risk in term births.

Previous studies have suggested that environmental lead exposure increases the risk of hypertension in the general population. In this article, the authors used the 1998 linked birth/infant death database of the United States to examine the association between environmental lead level and the occurrence of pregnancy-induced hypertension (PIH). Yearly summaries of environmental lead levels were abstracted from the US Environmental Protection Agency's air pollution databases, and linked with birth/infant death records by state codes. Generalized estimating equations (GEEs) were used to evaluate the odds ratios of PIH associated with environmental lead measured at ecological levels, with adjustment for maternal age, race, education level, marital status, parity, and adequacy of prenatal care measured at individual levels, stratified by maternal cigarette smoking. A total of 2,994,072 women pregnant in 1998 were included in this study. With the first quartile of lead level as the reference group, the odds ratio for PIH among all study subjects in the second quartile of seasonal average lead level at conception was 1.07 (95% CI: 1.05–1.08), and odds ratios in the third and fourth quartiles were 1.22 (95% CI: 1.20–1.25) and 1.16 (95% CI: 1.15–1.18), respectively. The odds ratios for the second, third, and fourth quartiles of seasonal average lead level at birth were 1.07 (95% CI: 1.05–1.09), 1.21 (95% CI: 1.19–1.23), and 1.15 (95% CI: 1.13–1.17), respectively. The risk of PIH increased by 4% per 0.05 μg/m 3 increase in seasonal average lead level at conception and birth, in both smokers and nonsmokers. These results suggest that higher environmental lead levels increase the risk of PIH.

Aims: Identification of women at high risk of intra-twin birth weight discordance is helpful in obstetric care of these pregnancies. The aim of this study is to establish an intra-twin birth weight discordance prediction model. Methods: We created an intra-twin birth weight discordance prediction model by logistic regression, based on the 1995–1997 register twin birth data of the USA. The twin sets were randomly divided into two groups: group 1 to establish the prediction model and group 2 to validate the prediction model. Intra-twin birth weight discordance was defined as birth weight discordance >25%. The prediction model was validated by receiver operating characteristic curve. Results: A birth weight discordance prediction model including maternal age (β = 0.069), parity (β = 0.250), fetal gender concordance (β = 0.041), maternal hypertension (β = 0.368), eclampsia (β = 0.316), other medical complication (β = 0.165), and smoking (β = 0.164) was established, yielded a 0.558 area under the receiver operating characteristic curve. The sensitivity, specificity, and positive predictive values were 38.1, 69.7, and 10.8%, respectively, at the cut-off value of 0.09 in group 2. Conclusion: A birth weight discordance prediction model that includes seven variables available during pregnancy has been established with acceptable diagnostic performance.

The purpose of this study was to assess the risk of neonatal death and morbidity in vertex-nonvertex second twins according to the mode of delivery and birth weight.Data from a retrospective cohort study that was based on all twin births in the United States (1995-1997) were used.A total of 15,185 vertex-nonvertex second twins were classified into 3 groups: (1) both twins were delivered by cesarean delivery (37.7%), (2) both twins were delivered vaginally (46.8%), and (3) the second twin was delivered by cesarean delivery after vaginal delivery of the first twin (15.5%). The risk of asphyxia-related neonatal deaths and morbidity was increased in the group in which both twins were delivered vaginally and the group in which both twins were delivered by cesarean delivery. The increase in neonatal death in the group in which both twins were delivered vaginally was stronger in the birth weight of1500 g. In contrast, in the group in which both twins were delivered vaginally and the group in which the second twin was delivered by cesarean delivery after the first twin was delivered vaginally, the increase in neonatal morbidity was greater in the group in which the birth weight was 1500 to 4000 g.The risk of neonatal death and morbidity in second-born twins is higher in the group in which both twins were delivered vaginally and the group in which the second twin was delivered by cesarean delivery after the first twin was delivered vaginally compared with the group in which both twins were delivered by cesarean delivery.

Objective: To assess the determinants of breast-feeding initiation and duration at the population level in Alberta, Canada. Methods: Determinants of breast-feeding were assessed based on data from a sample of 1 1 13 women, who represented 150 898 fertile women in Alberta, in the second cycle of the National Population Health Survey conducted 1996-97. Logistic regression analysis was used to estimate the independent effects of various determinants of breast-feeding initiation and duration dichotomized at 4 weeks, 8 weeks, 12 weeks, and 6 months postpartum. Ali analyses used analytic weights to take both the average design effect and population weights for the complex survey design into account. Results: The proportion of breast-feeding initiation was 85.6%. It was observed that 71.3% of mothers continued breast-feeding for at least 3 months, and 37.2% of mothers breast-fed their infants for more than 6 months. Determinants of breast-feeding initiation were marital status, education, maternal smoking behaviour, and annual family income. White women and women who were older than 35 years of age were more likely to continue breast-feeding for longer periods, whereas those who smoked during pregnancy were less likely to breast-feed their infants for extended periods. The primary reasons for weaning were breast problems at less than 1 week, insufficient milk production during weeks 1 to 12, and infants who weaned themselves after 3 months. Conclusions: Smoking cessation during pregnancy, adequate treatment of early breast problems, and breast-feeding promotion campaigns targeting socioeconomically disadvantaged populations could serve to increase breast-feeding in Canada.

Objective The purpose of this study was to assess the risk of neonatal death in the second twin. Study design We carried out a retrospective cohort study of 128,219 live born second twins in the United States for the years 1995 through 1997. The study subjects were divided into 3 groups: second twins who were delivered by cesarean delivery after vaginal delivery of the first twin (group 1), both twins delivered vaginally (group 2), and both twins delivered by cesarean delivery (group 3). Results The risk of asphyxia-related neonatal deaths was increased in groups 1 and 2; the increased risk in group 1 was stronger in term births than in preterm births. Conclusion The risk of neonatal deaths, especially for term infants with asphyxia-related deaths, is increased for the second twins who are delivered by cesarean delivery after vaginal delivery of the first twins.

Objective To estimate the occurrence and to assess clinical predictors of emergent cesarean delivery in the second twin after vaginal delivery of the first twin. Methods We conducted a population-based cohort study, using the 1995-1997 linked mother/infant twin data from the United States. The adjusted risk ratios and population attributable risks of clinical predictors of emergent cesarean delivery in second twins were estimated for the overall study sample and for those born at less than 36 or 36 weeks or more of gestation. Results Among the 61,845 second twin births with the first twin delivered vaginally, 5,842 (9.45%) were delivered by cesarean. The cesarean delivery rate was increased in infants born to mothers with medical or labor and delivery complications. Breech and other malpresentations were the most important predictors of emergent cesarean delivery for the second twin (population attributable risk 33.2%; 95% confidence interval 31.8%, 34.6%). Operative vaginal delivery of the first twin was associated with a decreased risk of cesarean delivery for the second twin. Prediction of emergent cesarean for the second twin by clinical factors was stronger in term births than preterm births. Conclusion In the general population, the cesarean delivery rate for the second twin after vaginal delivery of the first twin is approximately 9.5%. With the presence of breech and other malpresentations, the need for emergent cesarean delivery of the second twin after vaginal delivery of the first twin is increased by 4-fold. Level of evidence II-2

In this retrospective cohort of 165,188 singleton pregnancies and 44,674 multiple-fetal pregnancies in Canada from 1984 to 2000, we compared the incidence of maternal complications. Multiple gestation pregnancies were associated with significant increases in cardiac morbidity, haematologic morbidity, amniotic fluid embolus, pre-eclampsia, gestational diabetes, postpartum haemorrhage, prolonged hospital stay, the need for obstetric intervention, hysterectomy and blood transfusion. Multiple gestation pregnancies are associated with an increased risk of morbidity for the mother. This should be taken into consideration in antenatal care of these women.

This prospective cohort study designed to assess the effect of folic acid supplementation in pregnancy on the risk of preeclampsia (PE) took place in Ottawa, ON and Kingston, ON, Canada, from September 1, 2002 to August 31, 2008. Pregnant women, less than 20 weeks gestational age were recruited and delivered in the Ottawa region and the Kingston General Hospital. Demographic characteristics of the study participants and the patterns of supplementation of folic acid were described and occurrence of PE between women with folic acid supplementation during pregnancy and women without were compared. Multiple logistic regression was used in the estimation of the independent effect of supplementation of folic acid. Additional analyses assessing the effect of low RBC and serum folate and dose-response relationship were performed. Analyses were performed in all study participants, and then in high risk and low risk sub-groups, respectively. A total of 7,669 participants were included in the final analysis. Ninety five percent of the study participants were taking folic acid supplementation in early second trimester. The rate of PE was lower in the supplementation group than in the no supplementation group, and the difference was statistically significant in high risk women. Similar patterns of associations were observed in analysis by RBC and serum folate levels and in dose-response analysis. Folic acid supplementation in pregnancy may reduce PE risk in pregnant women, especially in those women with increased risk of developing PE.

to assess the association between neighbourhood family income and adverse birth outcomes.we conducted a retrospective cohort study of 334 231 singleton births during 2004 and 2006 based on the Niday Perinatal Database from Ontario. Median neighbourhood family incomes from the 2001 Canadian census were linked with the Niday Perinatal Database by dissemination areas. Generalized estimating equations were applied to estimate the odds ratios of adverse birth outcomes associated with lower neighbourhood income, with adjustment for maternal confounding variables at the individual level.compared with the highest neighbourhood income quintile, mothers from the lowest quintile were at increased risk of having small for gestational age neonates (OR 1.51; 95% CI 1.46 to 1.57), low birth weight (OR 1.43; 95% CI 1.36 to 1.50), preterm birth (OR 1.17; 95% CI 1.12 to 1.23), low Apgar score (7) at five minutes (OR 1.32; 95% CI 1.21 to 1.44), and stillbirth (OR 1.39; 95% CI 1.19 to 1.62). The risks of women from the lowest income quintiles delivering a macrosomic baby (OR 0.81; 95% CI 0.79 to 0.84) or a large for gestational age baby (OR 0.82; 95% CI 0.80 to 0.85) were significantly decreased. No difference in risk of congenital anomaly was found among different income quintiles.a lower level of neighbourhood income is associated with increased risks of small for gestational age babies, low birth weight, preterm birth, low Apgar score at five minutes, and stillbirth.

To estimate whether the use of specific types of assisted reproductive technology (ART) is associated with an increased risk of placenta-mediated pregnancy complications, which include preeclampsia, stillbirth, small for gestational age at birth, and placental abruption.A population-based retrospective cohort study was conducted on singleton pregnancies conceived by different types of ART based on the 2004-2007 Ontario Niday Perinatal Database. Patients with fetal anomalies and maternal health problems were excluded as important confounders. Three exposed groups were created by the subtype of ART, including in vitro fertilization with or without intracytoplasmic sperm injection, intrauterine insemination, and ovulation induction. The nonexposed groups were the singleton pregnancies conceived naturally. For each exposed woman, four women from the nonexposed group were randomly matched by maternal age and parity.There were 2,118 exposed participants and 8,420 matched nonexposed participants in the study. The sample size provided 80% power for a relative risk of 2.0 of placenta-mediated adverse pregnancy outcomes with ART. After adjustment of potential confounders, including smoking, delivery hospital level, initiating time of prenatal care, average neighborhood income, fetal sex, and previous cesarean delivery, there was no association observed between different types of ART groups and the composite of placenta-mediated pregnancy complications. Intrauterine insemination was associated with a significantly increased risk of preeclampsia (12 [2.67%] odds ratio 2.2, 95% confidence interval 1.04-5.04) compared with the corresponding control group (23 [1.29%]).Assisted reproductive technology is not associated with an increased risk of the composite outcome of placenta-mediated pregnancy complications among singleton pregnancies.II.

To assess the association between fetal macrosomia and adolescent obesity. Longitudinal cohort study of the association between macrosomia and adolescent obesity. Between 1 October 2005 and 1 February 2007, a follow-up study of live-born infants born in 1993–1995 in Wuxi, a suburban area of Shanghai, was conducted. Subjects with birth weight > 4000 g were selected as the exposed. For each exposed subject, one subject with a birth weight of 2500–4000 g, matched by year of birth, sex of infant, and type of institute at birth, was chosen as non-exposed. Clinical data were collected by structured interview and physical examination. Obesity was defined as body mass index (weight (kg)/height (m2)) higher than the sex-age-specific criteria by the working group on obesity in China. Distribution of baseline characteristics and adolescent obesity rate between the exposed and non-exposed groups was compared. A total of 1435 pairs of exposed and non-exposed subjects were included in the final analysis. No major difference in baseline characteristics (other than birth weight) was found between the exposed and non-exposed groups. Obesity rate was significantly higher in the exposed group (2.9%) than in the non-exposed group (1.6%). Adolescent obesity rates were 1.4, 1.9, 2.6, and 5.6%, respectively, in study subjects with a birth weight of 2500–3499, 3500–3999, 4000–4499, and ⩾4500 g. The association between birth weight and adolescent obesity remained essentially the same when mother's demographic and anthropometric factors, breast feeding, and adolescent life-style factors were adjusted. Compared with infants of normal birth weight, infants with birth weight >4000 g, especially those >4500 g, are at increased risk of adolescent obesity.

The purpose of this study was to compare risk factors between placental abruption and placenta previa among primiparous and multiparous singleton pregnancies. We analyzed data from a population-based retrospective cohort with singleton pregnancies in the United States for 1995 to 2000. Maternal risk factors for placenta previa and placental abruption were examined using multiple logistic regressions. A total of 5,630,854 primiparous and 11,026,768 multiparous singleton pregnancies were available for final analyses after excluding subjects with missing information on outcomes or important exposures. Placental abruption was recorded in 4.8 per 1000 primiparous singleton births and 5.9 per 1000 multiparous singleton pregnancies. The occurrence of placenta previa was 1.9 per 1000 primiparous singleton pregnancies and 3.9 per 1000 multiparous singleton pregnancies. The effects of maternal age, race, parity, and previous cesarean section were stronger on placenta previa than on placental abruption, and the effects of cigarette smoking, alcohol drinking, and prenatal care were stronger on placental abruption than on placenta previa. A composite outcome of selected medical and pregnancy complications was related with placental abruption but not with placental previa. Placental abruption is more likely to be affected by conditions occurring during pregnancy, and placenta previa is more likely to be affected by conditions existing prior to pregnancy.

To examine the association between placenta previa with maternal race and its variations by country of origin among Asian women.Retrospective cohort study.We analyzed data from a population-based retrospective cohort study of 16,751,627 pregnancies in the US. The data were derived from the national linked birth/infant mortality database for the period 1995-2000. Multiple logistic regressions were used to describe the relationship between placenta previa and race as well as country of origin among Asian women.About 3.3 per 1,000 pregnancies were complicated with placenta previa among white women, while the corresponding figures for black women and women of other races were 3.0 and 4.5 per 1,000 pregnancies, respectively. The excess risk remained substantial and significant after adjustment for confounders for women of other races compared to white women. The frequencies of placenta previa among Chinese, Japanese, Filipino, Asian Indian, Korean, Vietnamese and other Asian or Pacific Islander were 5.6, 5.1, 7.6, 4.5, 5.9, 4.4 and 4.4 per 1,000 pregnancies, respectively. The adjusted odds ratios ranged from 1.39 to 2.15 among Asian women by country of origin, with the lowest for Japanese and Vietnamese and the highest for Filipino women in our study.Asian women have excess risk of placenta previa compared with white women. Major variation exists in placenta previa risk among Asian women, with the lowest risk in Japanese and Vietnamese women and the highest risk in Filipino women.

Objective To examine the possible association between oral contraceptive use and adverse birth outcomes. Study design We conducted a population-based cohort study of pregnant women who used oral contraceptives within 3 months before their last menstrual period. Subjects were divided into three groups, according to the interval (0–30, 31–60, and 61–90 days) between the dispensing date and their last menstrual period. For each exposed subject, 4 subjects without exposure to oral contraceptives were individually matched by infant's year of birth and plurality and by mother's age and parity. Results Oral contraceptive use within 30 days prior to the last menstrual period was associated with increased risks of very low birth weight (OR: 3.24, 95% CI: 1.18, 8.92), low birth weight (OR: 1.93, 95% CI: 1.17, 3.20), and preterm birth (OR: 1.61, 95% CI: 1.01, 2.55); however, oral contraceptive use 31–90 days prior to the last menstrual period did not increase the risk of low birth weight or preterm birth. Conclusion Our results indicate the use of oral contraceptives near the time of conception may be associated with an increased risk of low birth weight and preterm birth.

To examine prescription Food and Drug Administration (FDA) C, D and X drugs in general obstetric population. Historical cohort study. A total of 18 575 women who gave a birth in Saskatchewan between January 1997 and December 2000 were included. Among them, 3604 (19.4%) received FDA C, D or X drugs at least once during pregnancy. The pregnancy exposure rates were 15.8, 5.2 and 3.9%, respectively, for category C, D and X drugs, and were 11.2, 7.3 and 8.2%, respectively, in the first, second and third trimesters. Salbutamol (albuterol), trimethoprim/sulfamethoxazole (co-trimoxazole), ibuprofen, naproxen and oral contraceptives were the most common C, D, X drugs used during pregnancy. About one in every five women uses FDA C, D and X drugs at least once during pregnancy, and the most common prescription drugs in pregnancy are antiasthmatic, antibiotics, nonsteroid anti-inflammation drugs, antianxiety or antidepressants and oral contraceptives.

Most previous studies on the effect of paternal age have focused on the association of advanced paternal age with congenital anomalies. The objective of this study was to determine whether paternal age is associated with the risk of adverse birth outcomes independent of maternal confounders. We carried out a retrospective cohort study of 2 614 966 live singletons born to married nulliparous women aged 20-29 years between 1995 and 2000 in the USA. Multiple logistic regressions were applied to estimate the independent effect of paternal age on adverse birth outcomes. Compared with infants born to fathers aged 20-29 years infants fathered by teenagers (less than 20 years old) had an increased risk of preterm birth [odds ratio (OR) = 1.15 95% confidence interval (CI): 1.10 1.20] low birth weight (OR = 1.13 95% CI: 1.08 1.19) small-for-gestational-age births (OR = 1.17 95% CI: 1.13 1.22) low Apgar score (OR = 1.13 95% CI: 1.01 1.27) neonatal mortality (OR = 1.22 95% CI: 1.01 1.49) and post-neonatal mortality (OR = 1.41 95% CI: 1.09 1.82). Advanced paternal age (greater than or equal to 40 years) was not associated with the risk of adverse birth outcomes. Teenage fathers carry an increased risk of adverse birth outcomes that is independent of maternal confounders whereas advanced paternal age is not an independent risk factor for adverse birth outcomes. (authors)

Purpose To estimate the frequency of exposure to prescription Food and Drug Administration (FDA) category C, D, and X drugs in pregnant women, and to analyze the maternal characteristics associated with such an exposure. Methods A 50% random sample of women who gave a birth in Saskatchewan between January 1, 1997 and December 31, 2000 was chosen for the study. The rate of exposure to FDA category C, D, or X drugs recorded in the pharmacist database was estimated. Associations of exposure to FDA category C, D, and X drugs with maternal characteristics were evaluated using multiple logistical regression, with adjusted odds ratios (ORs) and its 95% confidence intervals (CIs) as the association measures. Results A total of 18 575 women were included in this study. Among them, 3604 (19.4%) had exposure to one or more FDA category C, D, and X drugs during pregnancy. Category C drugs were the most frequently used drugs (15.8%), followed by D drugs (5.2%), and X drugs (3.9%). Women with chronic health conditions had fourfold at increased risk of exposure than women without. Regardless of health status, women who were

To estimate the rate of prescription trimethoprim/sulfamethoxazole use in pregnancy, and to analyse the association between maternal characteristics and use of trimethoprim/sulfamethoxazole in pregnancy.A population-based study was conducted based on a 50% random sample of women who gave a birth in Saskatchewan between 1 January 1997 and 31 December 2000. The rate of trimethoprim/sulfamethoxazole use during pregnancy was estimated. The exposure in each trimester was also estimated. Associations between maternal characteristics and pregnancy trimethoprim/sulfamethoxazole use were evaluated using multiple logistical regression with adjusted odds ratios (ORs) and 95% confidence intervals (CIs) as the association measures.A total of 18,575 women who gave a birth in Saskatchewan during the study period were included in the analysis. Among them, 596 (3.2%) had at least 1 prescription for trimethoprim/sulfamethoxazole during pregnancy, 389 (2.1%) in the first trimester, 208 (1.1%) in the second trimester, and 195 (1.1%) in the third trimester. Women with chronic health conditions (6.2%) had a 2-fold increased risk of exposure compared to women without a chronic health condition (2.8%). Younger women (20 years) with parity/=3 and women on Saskatchewan assistance plan were also at increased risk. There were variations in exposure by trimester. For example, teenage women without chronic health conditions were at increased risk of use in the second and third trimester.Some 3.2% of women are exposed to trimethoprim/sulfamethoxazole during pregnancy. Women with chronic health problems, of younger age, and of lower socioeconomic status are at elevated risk of exposure to trimethoprim/sulfamethoxazole during pregnancy.

To compare the effects of new-onset hypertension (NOH) in late pregnancy on fetal growth in singletons and twins.A retrospective cohort study was conducted to evaluate the effect of NOH on fetal growth in 17, 720, 900 singletons and 463, 104 twins born in the United States between 1995 and 2000.NOH was associated with lower mean birth weight in both preterm and term singletons. Increased risk of low birth weight and decreased risk of high birth weight was associated with NOH in preterm and term singletons. NOH was associated with increased risk for small-for-gestational-age (SGA) births and decreased risk for large-for-gestational-age (LGA) births in preterm singletons, whereas it was associated with increased risk of both SGA and LGA births in term singletons. NOH was associated with higher mean birth weight in early preterm twins, and lower mean birth weight in term twins. Decreased risk for low birth weight was found in the NOH group among early preterm twins, and increased risk for low birth weight in term twins. NOH was associated with increased risk of SGA births and decreased risk for large-for-gestational-age (LGA) births in early preterm twins, while increased risk of SGA births in term twins.NOH is associated with slower fetal growth in singletons delivered at different gestational ages, but the effect varies in twins depending on gestational age at delivery with faster growth in early preterm twins.

The purpose of this study was to investigate to what extent the Society of Obstetricians and Gynecologists of Canada (SOGC) guidelines on dystocia are being followed, and whether adherence to the guidelines is related to cesarean section rates. Data were extracted from a maternity database for nulliparous women with singleton, cephalic pregnancies at 37 or more completed weeks of gestation for a 4-year period. Patients delivered by elective cesarean section were excluded. Data were examined to determine whether those who had a cesarean section for dystocia in the first stage of labor fulfilled SOGC guidelines. In addition, the obstetricians were divided into two groups (high or low) according to their cesarean section rate for dystocia to determine whether a higher section rate was associated with an increased guideline violation rate. There were 239 nulliparous women who had a cesarean section for dystocia in the first stage of labor. The guidelines were followed in 47.7% of spontaneous labors and 77.5% of inductions. The mean section rate for dystocia in the first stage of labor was 10.8% in the high group and 6.6% in the low group, and the incidence of guideline violations in these groups was 48.0% and 39.6%, respectively ( P = 0.07). The study had a power of 0.88 to detect a 40% difference in guideline violation rates between the two groups. We conclude that many women have cesarean section for dystocia performed without fulfilling SOGC guidelines.

BACKGROUND: Teenage pregnancy may be associated with some forms of congenital anomalies. The objective of this study was to identify the types of congenital anomalies associated with teenage pregnancy. METHODS: We carried out a retrospective cohort study of 5 542 861 nulliparous pregnant women younger than 35 years of age with a live singleton birth between 1995 and 2000 in the USA. RESULTS: Compared with adult pregnancy (20–34 years old), and after adjustment for confounding variables, teenage pregnancy (13–19 years old) was associated with increased risk of central nervous system anomalies [odds ratio (OR) 1.08; 95% confidence interval (CI): 1.01, 1.16], gastrointestinal anomalies (OR: 1.39; 95% CI: 1.31, 1.49) and musculoskeletal/integumental anomalies (OR: 1.06; 95% CI: 1.03, 1.10). The teenage pregnancy associated increase in risk for central nervous system anomalies was mainly attributable to anomalies other than anencephalus, spina bifida/meningocele and hydrocephalus and microcephalus; for gastrointestinal anomalies the risk was mainly attributable to omphalocele/gastroschisis; and for musculoskeletal/integumental anomalies the risk was mainly attributable to cleft lip/palate and polydactyly/syndactyly/adactyly. No increased risk was found for circulatory/respiratory anomalies, urogenital anomalies, or Down’s syndrome. CONCLUSIONS: Teenage pregnancy increases the risks of congenital anomalies in central nervous, gastrointestinal and musculoskeletal/integumental systems.

Background: Previous studies have found that inadequate prenatal care was associated with increased neonatal mortality in the general pregnant women. Aims: To examine the association between adequacy of prenatal care and neonatal mortality in the presence and absence of antenatal high-risk conditions. Methods: We conducted a retrospective cohort study of infants based on 1995–2000 vital statistics data in the USA. The relative risk for neonatal death associated with adequacy of prenatal care was estimated by multivariate logistic regressions with adjustment of confounding factors. Results: Inadequate prenatal care was associated with increased neonatal mortality when pregnancies were complicated by anaemia, cardiac disease, lung disease, chronic hypertension, diabetes, renal disease, pregnancy-induced hypertension, and previous preterm/small-for-gestational-age birth. The observed association also existed in the absence of these antenatal high-risk conditions. Overutilisation of prenatal care was associated with increased risk of neonatal deaths in both the presence and the absence of antenatal high-risk conditions. When gestational age at delivery and birthweight were further adjusted, the observed association between inadequate prenatal care and neonatal mortality was not significant in pregnancies with various high-risk conditions. Conclusions: Inadequate prenatal care is associated with increased neonatal death in both the presence and the absence of antenatal high-risk conditions. The observed association between inadequate prenatal care and neonatal mortality may be mediated by increased risk of preterm delivery and low birthweight in these pregnancies. Overutilisation of prenatal care is associated with potential risks for fetal and neonatal development, leading to increased neonatal mortality.

Objective To quantify the risk of placenta praevia and placental abruption in singleton, second pregnancies after a caesarean delivery of the first pregnancy. Design Retrospective cohort study. Setting Linked birth and infant mortality database of the USA between 1995 and 2000. Population A total of 5 146 742 singleton second pregnancies were available for the final analysis after excluding missing information. Methods Multiple logistic regressions were used to describe the relationship between caesarean section at first birth and placenta praevia and placental abruption in second-birth singletons. Main outcome measures Placenta praevia and placental abruption. Results Placenta praevia was recorded in 4.4 per 1000 second-birth singletons whose first births delivered by caesarean section and 2.7 per 1000 second-birth singletons whose first births delivered vaginally. About 6.8 per 1000 births were complicated with placental abruption in second-birth singletons whose first births delivered by caesarean section and 4.8 per 1000 birth in second-birth singletons whose first births delivered vaginally. The adjusted odds ratio (95% CIs) of previous caesarean section for placenta praevia in following second pregnancies was 1.47 (1.41, 1.52) after controlling for maternal age, race, education, marital status, maternal drinking and smoking during pregnancy, adequacy of prenatal care, and fetal gender. The corresponding figure for placental abruption was 1.40 (1.36, 1.45). Conclusion Caesarean section for first live birth is associated with a 47% increased risk of placenta praevia and 40% increased risk of placental abruption in second pregnancy with a singleton.

Objective To determine the potential pathway of the association between teenage pregnancy and neonatal and postneonatal mortality. Study Design and setting We carried out a retrospective cohort study of 4,037,009 nulliparous pregnant women under 25 years old who had a live singleton birth during 1995 to 2000, based on linked birth and infant death data set of the United States. Results Teenage pregnancy (10–19 years old) was associated with increased neonatal mortality (odds ratio [OR]: 1.20, 95% confidence interval [CI] = 1.16–1.24) and postneonatal mortality (OR: 1.47, 95% CI = 1.41–1.54) after adjustment for potential confounders. With further adjustment for weight gain during pregnancy, teenage pregnancy was still associated with increased risk of neonatal (OR: 1.23, 95% CI = 1.19–1.28) and postneonatal mortality (OR: 1.48, 95% CI = 1.42–1.55). When adjustment was made for gestational age at birth, there was no association of teenage pregnancy with neonatal mortality (OR: 0.98, 95% CI = 0.95–1.02), whereas there was significant association with postneonatal mortality (OR: 1.40, 95% CI = 1.34–1.46). Conclusion The increased risk of neonatal death associated with teenage pregnancy is largely attributable to higher risk of preterm births, whereas increased postneonatal mortality is independent of the known confounders and gestational age at birth.

Objective To assess the effect of pregnancy-induced hypertension (PIH) on infant mortality in different birthweight centiles (small for gestational age [SGA], appropriate for gestational age [AGA], and large for gestational age [LGA]) and gestational ages (early preterm, late preterm, and full term). Design Retrospective cohort study. Setting Linked birth and infant death data set of USA between 1995 and 2000. Population A total of 17 464 560 eligible liveborn singleton births delivered after 20th gestational week. Methods Multivariate logistic regression models were applied to evaluate the association between PIH and infant mortality, with adjustment of potential confounders stratified by birthweight centiles and gestational age. Main outcome measure Infant death (0–364 days) and its three components: early neonatal death (0–6 days), late neonatal death (7–27 days), and postneonatal death (28–364 days). Results PIH was associated with decreased risks of infant mortality, early neonatal mortality, and late neonatal mortality in both preterm and term SGA births, and PIH was associated with lower postneonatal mortality in preterm SGA births. PIH was associated with decreased risks of infant mortality, early neonatal mortality, late neonatal mortality and postneonatal mortality in preterm AGA births. Decreased risk of infant mortality and early neonatal mortality was associated with PIH in early preterm LGA births. Conclusions The association between PIH and infant mortality varies depending on different birthweight centiles, gestational age, and age at death. PIH is associated with a decreased risk of infant mortality in SGA births, preterm AGA births, and early preterm LGA births.

Aims: To establish reference values of semen parameters in a residential, geographic, and age representative sample of healthy Chinese men. Methods: From a national study of 1,191 healthy Chinese men, semen samples were analyzed from 105 subjects whose wives or partners were pregnant within the 12 months prior to the date when the semen sample was taken. Results: The means, fifth percentiles, and percentages lower than the WHO criteria for semen parameters were, respectively: 75.8 × 106/ml, 17.8 × 106/ml, and 6.7% for sperm concentration; 206.9 × 106/ejection, 26.3 × 106/ejection, and 6.7% for total sperm count; 18.9, 3.0, and 79.1% for rapid progressive motility; 49.1, 25.3, and 52.4% for sperm progressive motility; 73.8, 49.3, and 45.7% for sperm viability, and 49.5, 25.2, and 9.5% for normal morphology. Conclusion: The values of semen parameters for Chinese men are lower than the WHO criteria, especially for rapid progressive motility, progressive motility, and sperm viability, and a different standard for Chinese may be needed.

To assess the association between new-onset hypertension in late pregnancy (NOH) and fetal and infant mortality in early preterm, late preterm, and full-term twins.We conducted a retrospective cohort study in 275, 316 twins in 1995-1997 based on multiple birth registration dataset of USA. Generalized estimating equations (GEEs) was used to evaluate the odds ratios (OR) of fetal and infant death (at individual level) associated with NOH, with adjustment of potential confounders at both twin set level and individual level.The risks for early neonatal death (OR = 0.52, 95% CI: 0.36, 0.76) and late neonatal death (OR = 0.57, 95% CI: 0.37, 0.87) were decreased in early preterm twins born to mothers with NOH compared with early preterm twins born to mothers with normal blood pressure. The decreased risks for fetal death (OR = 0.40, 95% CI: 0.30, 0.53; OR = 0.46, 95% CI: 0.53, 0.65) and infant death (OR = 0.35, 95% CI: 0.28, 0.44; OR = 0.68, 95% CI: 0.51, 0.91) were associated with NOH in both early and late preterm twins, whereas no association between NOH and fetal/infant mortality were observed in full-term twins.NOH is associated with lower risk of fetal death and infant death in preterm twins.

To examine the association between maternal age, paternal age, and new-onset hypertension in late pregnancy.We carried out a retrospective cohort study of 9,302,675 pregnant women with live births in the United States between 1995 and 1998. Maternal and paternal ages were analyzed together using "couple age" in multivariate logistic regression models to reduce colinearity between maternal age and paternal age. The effect of paternal age was also analyzed with stratification of maternal age.Compared with couples with both a maternal and paternal age of 20 to 34 years, an older maternal age (above 35 years) was associated with an increased risk for new-onset hypertension, except for couples with a very young father (below 20 years). Younger maternal age (below 20 years) was associated with a decreased risk for new-onset hypertension, except for couples with a very old father (above 45 years). There was no significant association between paternal age and new-onset hypertension with stratification of maternal age.Increased risk for new-onset hypertension in late pregnancy is significantly associated with advancing maternal age, whereas there is no association between paternal age and new-onset hypertension in late pregnancy.

Objective The purpose of this study was to assess the safety of the use of selective serotonin reuptake inhibitors in pregnancy. Study design We carried out a retrospective cohort study of 972 pregnant women who had been given at least 1 selective serotonin reuptake inhibitor prescription in the year before delivery and 3878 pregnant women who did not receive selective serotonin reuptake inhibitors and who were matched by the year of the infant's birth, the type of institute at birth, and the mother's postal code from 1990 to 2000 in the Canadian province of Saskatchewan. Results The risks of low birth weight (adjusted odds ratio, 1.58; 95% CI, 1.19, 2.11), preterm birth (adjusted odds ratio, 1.57; 95% CI, 1.28, 1.92), fetal death (adjusted odds ratio, 2.23; 95% CI, 1.01, 4.93), and seizures (adjusted odds ratio, 3.87; 95% CI, 1.00, 14.99) were increased in infants who were born to mothers who had received selective serotonin reuptake inhibitor therapy. Conclusion The use of selective serotonin reuptake inhibitors in pregnancy may increase the risks of low birth weight, preterm birth, fetal death, and seizures.

To assess the risk of neonatal mortality and morbidity in vertex-vertex second twins according to mode of delivery and birth weight.Data from a historical cohort study based on a twin registry in the US (1995-1997) were used. Multivariate logistic regression was used to control for maternal age, race, marital status, cigarette smoking during pregnancy, parity, medical complications, gestational age, and other confounders.A total of 86 041 vertex-vertex second twins were classified into two groups: second twins delivered by cesarean section after cesarean delivery of first twin (C-C) (43.0%), second twins whose co-twins delivered vaginally (V-X) (57.0%). In infants of birth weightor=2500 g group, the risks of noncongenital anomaly-related death (adjusted odds ratio (aOR): 4.64, 95% confidence interval (95% CI): 1.90, 13.92), low Apgar score (aOR: 2.39, 95% CI: 1.43, 4.14), and ventilation use (aOR: 1.31, 95% CI: 1.18, 1.47) were higher in the V-X group compared with the C-C group. No asphyxia-related neonatal deaths occurred in C-C group, whereas the incidence of this death was 0.04% in the V-X group.The risks of neonatal mortality and morbidity are increased in vertex-vertex second twins with birth weightor=2500 g whose co-twins delivered vaginally compared with second twins delivered by cesarean section after cesarean delivery of first twin.

Although previous studies have found that maternal smoking decreases the risk of pregnancy-induced hypertension (PIH), the difference of this effect between primiparous and multiparous women has not been well studied and the results of the exposure-response relationships between maternal smoking and PIH are inconsistent. No previous study has specifically examined the relationship between maternal smoking and eclampsia.We analysed data from a population-based retrospective cohort study of 3 153 944 singleton pregnancies in the US. The data were derived from the national linked birth/infant mortality database for 1998. Multiple logistic regressions were used to describe the relationship between cigarette smoking and PIH and eclampsia.The adjusted odds ratios (ORs) [95% confidence intervals (95% CIs)] for PIH were 0.80 (0.77-0.83) for primiparous women and 0.81 (0.78-0.83) for multiparous women among smokers compared with non-smokers. The corresponding adjusted ORs (95% CIs) for eclampsia were 0.74 (0.66-0.82) and 0.75 (0.68-0.83), respectively. For PIH, the adjusted OR (95% CI) for smokers vs non-smokers were 0.82 (0.79-0.86), 0.81 (0.78-0.83), 0.80 (0.77-0.83), and 0.88 (0.79-0.98), respectively, for 1-5, 6-10, 11-20, and20 cigarettes per day (test for trend: P = 0.86). The corresponding figures for eclampsia were 0.85 (0.75-0.95), 0.74 (0.66-0.82), 0.68 (0.58-0.78), and 0.73 (0.49-1.04), respectively (test for trend: P = 0.02).Maternal cigarette smoking decreases the risk of PIH and eclampsia, with a significant inverse exposure-response relationship apparent for eclampsia.

Background: Small for gestational age (SGA) is one of the major determinants of perinatal mortality and morbidity, and may relate in adult diseases. Early prediction of SGA could be helpful for health care providers and public health workers in guiding antenatal management and prevention. The reported methods of SGA prediction are not satisfactory because the diagnostic performance is poor and the interval between prediction and delivery is too short. Aims: To establish a SGA prediction model for twin pregnancies based on variables obtainable in early gestation. Methods: We used a large twin registry United States data (1995–1997). The study subjects were randomly divided into two groups: group 1 to establish the prediction model by logistic regression and group 2 to validate the prediction model. SGA was defined as birth weight for gestational age z scores less than 10th percentiles. Pair of twin was the unit of analysis. Two sets of multiple logistic regression analyses with different outcome measures – one or both twins SGAs and both twins SGAs – were used to establish the prediction model. Results: The sensitivity, specificity, and positive predictive value were 52.3, 62.5, and 21.5%, respectively, at the cutoff value 0.16 in a SGA prediction model based on maternal race, education, marital status, parity, prenatal care visit initiation, cigarette smoking, and paternal race. Conclusions: A prediction model based on determinants that can be obtained at early gestation might be useful in the management of pregnancies with high risk of SGA in twins.

In industrialized countries, 5-11% of infants are born preterm (

Objective This study was undertaken to estimate occurrence and explore clinical predictors of abdominal and vaginal operative delivery in vertex second twin after normal vaginal delivery of the first twin. Methods Data from a historical cohort study that was based on a twin registry in the United States (1995-1997) were used. Results Among 42,417 vertex second twins following normal vaginal delivery of the first twins, rates of abdominal and vaginal operative delivery were 6.3% and 8.3%, respectively. Cord prolapse, fetal distress, maternal complications, abnormal labor, and birth weight 25% larger than first twin were the most important predicators for operative deliveries. Fetal distress and cord prolapse had a stronger effect on abdominal than vaginal operative delivery. Conclusion In general population, abdominal and vaginal operative delivery rates were 6.3% and 8.3%, respectively, in vertex second twin after normal vaginal delivery of the first twin. The most important predictors for operative delivery are cord prolapse and fetal distress.

Objective The purpose of this study was to assess the risk of maternal morbidity and obstetric complications in women with triplet pregnancies and quadruplet and higher-order multiple pregnancies. Study design We compared the outcomes in women with triplet pregnancies (n = 5491) and quadruplet and higher-order multiple pregnancies (n = 423) with women with twin pregnancies (n = 152,238), with the use of the 1995 to 1997 Multiple Birth File of the United States. Results After an adjustment was made for important confounding factors, the risks of pregnancy-associated hypertension and eclampsia, anemia, diabetes mellitus, abruptio placenta, premature rupture of membrane, and cesarean delivery were increased in women with triplet pregnancies and quadruplet and higher-order multiple gestations than in women with twin pregnancies. A dose-response relationship was observed for pregnancy-associated hypertension, diabetes mellitus, and placental abruption, with higher odds ratios in women with quadruplet and higher-order multiple gestations than in women with triplet pregnancies. Conclusion The risks of maternal morbidity and obstetric complications are increased in triplet pregnancies and quadruplet and higher-order multiple pregnancies than in twin pregnancies; for certain outcomes, there is a dose-response relationship.

Objective The objective of the study was to evaluate the association between folic acid supplementation in early second trimester and the risk of developing preeclampsia. Study Design We carried out a prospective cohort study between October 2002-December 2005. We recruited women who had their prenatal care visit (12-20 weeks’ gestation) at the Ottawa Hospital and Kingston General Hospital. All charts for participants with a diagnosis of preeclampsia were audited and blindly adjudicated by 4 study investigators to validate the diagnosis. Results A total of 2951 pregnant women were included in the final analysis. Supplementation of multivitamins containing folic acid was associated with increased serum folate (on average 10.51 μmol/L), decreased plasma homocysteine (on average 0.39 μmol/L), and reduced risk of preeclampsia (adjusted odds ratio, 0.37; 95% confidence interval, 0.18-0.75). Conclusion Supplementation of multivitamins containing folic acid in the second trimester is associated with reduced risk of preeclampsia.

In this retrospective cohort of 165,188 singleton pregnancies and 44,674 multiple-fetal pregnancies in Canada from 1984 to 2000, we compared the incidence of maternal complications. Multiple gestation pregnancies were associated with significant increases in cardiac morbidity, haematologic morbidity, amniotic fluid embolus, pre-eclampsia, gestational diabetes, postpartum haemorrhage, prolonged hospital stay, the need for obstetric intervention, hysterectomy and blood transfusion. Multiple gestation pregnancies are associated with an increased risk of morbidity for the mother. This should be taken into consideration in antenatal care of these women.