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BackgroundIn light of the recent Great Recession, increasing attention has focused on the health consequences of economic downturns. The perinatal literature does not converge on whether ambient economic declines threaten the health of cohorts in gestation. We set out to test the economic stress hypothesis that the monthly count of cesarean deliveries (CD), which may gauge the level of fetal distress in a population, rises after the economy declines. We focus on male CD since the literature reports that male more than female fetuses appear sensitive to stressors in utero.MethodsWe tested our ecological hypothesis in California for 228 months from January 1989 to December 2007, the most recent data available to us at the time of our tests. We used as the independent variable the Bureau of Labor Statistics unadjusted total state employment series. Time-series methods controlled for patterns of male CD over time. We also adjusted for the monthly count of female CD, which controls for well-characterized factors (e.g., medical-legal environment, changing risk profile of births) that affect CD but are shared across infant sex.ResultsFindings support the economic stress hypothesis in that male CD increases above its expected value one month after employment declines (employment coefficient = -24.09, standard error = 11.88, p = .04). Additional exploratory analyses at the metropolitan level indicate that findings in Los Angeles and Orange Counties appear to drive the State-level relation.ConclusionsContracting economies may perturb the health of male more than female fetuses sufficiently enough to warrant more CD. Male relative to female CD may sensitively gauge the cohort health of gestations.

ObjectiveTo examine the association between maternal hospital diagnoses of obesity and risk of cerebral palsy (CP) in the child.Study designFor all California hospital births from 1991-2001, we linked infant and maternal hospitalization discharge abstracts to California Department of Developmental Services records of children receiving services for CP. We identified maternal hospital discharge diagnoses of obesity (International Classification of Diseases, 9th edition 646.1, 278.00, or 278.01) and morbid obesity (International Classification of Diseases, 9th edition 278.01), and performed logistic regression to explore the relationship between maternal obesity diagnoses and CP.ResultsAmong 6.2 million births, 67 200 (1.1%) mothers were diagnosed with obesity, and 7878 (0.1%) with morbid obesity; 8798 (0.14%) children had CP. A maternal diagnosis of obesity (relative risk [RR] 1.30, 95% CI 1.09-1.55) or morbid obesity (RR 2.70, 95% CI 1.89-3.86) was associated with increased risk of CP. In multivariable analysis adjusting for maternal race, age, education, prenatal care, insurance status, and infant sex, both obesity (OR 1.27, 95% CI 1.06-1.52) and morbid obesity (OR 2.56, 95% CI 1.79-3.66) remained independently associated with CP. On stratified analyses, the association of obesity (RR 1.72, 95% CI 1.25-2.35) or morbid obesity (RR 3.79, 95% CI 2.35-6.10) with CP was only significant among women who were hospitalized prior to the birth admission. Adjusting for potential comorbidities and complications of obesity did not eliminate this association.ConclusionsMaternal obesity may confer an increased risk of CP in some cases. Further studies are needed to confirm this finding.

ObjectiveTo estimate the association between vaginal birth after cesarean delivery (VBAC) rates and primary cesarean delivery rates in California hospitals.MethodsHospital VBAC rates were calculated using birth certificate and discharge data from 2009, and hospitals were categorized by quartile of VBAC rate. Multivariable logistic regression analysis was performed to estimate the odds of cesarean delivery among low-risk nulliparous women with singleton pregnancies at term in vertex presentation (nulliparous term singleton vertex) by hospital VBAC quartile while controlling for many patient-level and hospital-level confounders.ResultsThere were 468,789 term singleton births in California in 2009 at 255 hospitals, 125,471 of which were low-risk nulliparous term singleton vertex. Vaginal birth after cesarean delivery rates varied between hospitals, with a range of 0-44.6%. Rates of cesarean delivery among low-risk nulliparous term singleton vertex women declined significantly with increasing VBAC rate. When adjusted for maternal and hospital characteristics, low-risk nulliparous term singleton vertex women who gave birth in hospitals in the highest VBAC quartile had an odds ratio of 0.55 (95% confidence interval 0.46-0.66) of cesarean delivery compared with women at hospitals with the lowest VBAC rates. Each percentage point increase in a hospital's VBAC rate was associated with a 0.65% decrease in the low-risk nulliparous term singleton vertex cesarean delivery rate.ConclusionHospitals with higher rates of VBAC have lower rates of primary cesarean delivery among low-risk nulliparous women with singleton pregnancies at term in vertex presentation.Level of evidenceII.

ObjectiveTo estimate the risk of short-term complications in neonates born between 34 and 36 weeks by week of gestation.DesignThis is a retrospective cohort study.SettingDeliveries in 2005 in the United States of America.PopulationSingleton live births between 34 and 40 weeks gestational age.MethodsGestational age was subgrouped into 34, 35, 36 and 37–40 completed weeks. Statistical comparisons were performed using chi-square test and multivariable logistic regression models, with 37–40 weeks gestational age designated as referent.Main Outcome MeasuresPerinatal morbidities, including 5-minute Apgar scores, hyaline membrane disease, neonatal sepsis/antibiotics use, and admission to the intensive care unit.ResultsThere were 175,112 neonates born between 34 and 36 weeks in 2005. Compared to neonates born between 37 and 40 weeks, neonates born at 34 weeks had higher odds of 5-minute Apgar6 hours (aOR=9.78 [8.99–10.6]) and antibiotics use (aOR=9.00 [8.43–9.60]). Neonates born at 35 weeks were similarly at risk of morbidity, with higher odds of 5-minute Apgar 6 hours (aOR 5.53 [5.11–5.99] and NICU admission (aOR 11.3 [11.0–11.7). Further, neonates born at 36 weeks remain at higher risk of morbidity compared to deliveries at 37–40 weeks.ConclusionsWhile the risk of undesirable neonatal outcomes decreases with increasing gestational age, the risk of neonatal complications in late preterm births remains higher compared to infants delivered at 37–40 weeks gestation.

ObjectiveTo estimate the risk of short-term complications in neonates born between 34 and 36 weeks by week of gestation.DesignThis is a retrospective cohort study.SettingDeliveries in 2005 in the United States of America.PopulationSingleton live births between 34 and 40 weeks gestational age.MethodsGestational age was subgrouped into 34, 35, 36 and 37–40 completed weeks. Statistical comparisons were performed using chi-square test and multivariable logistic regression models, with 37–40 weeks gestational age designated as referent.Main Outcome MeasuresPerinatal morbidities, including 5-minute Apgar scores, hyaline membrane disease, neonatal sepsis/antibiotics use, and admission to the intensive care unit.ResultsThere were 175,112 neonates born between 34 and 36 weeks in 2005. Compared to neonates born between 37 and 40 weeks, neonates born at 34 weeks had higher odds of 5-minute Apgar6 hours (aOR=9.78 [8.99–10.6]) and antibiotics use (aOR=9.00 [8.43–9.60]). Neonates born at 35 weeks were similarly at risk of morbidity, with higher odds of 5-minute Apgar 6 hours (aOR 5.53 [5.11–5.99] and NICU admission (aOR 11.3 [11.0–11.7). Further, neonates born at 36 weeks remain at higher risk of morbidity compared to deliveries at 37–40 weeks.ConclusionsWhile the risk of undesirable neonatal outcomes decreases with increasing gestational age, the risk of neonatal complications in late preterm births remains higher compared to infants delivered at 37–40 weeks gestation.

The purpose of this study was to examine whether postterm gestational age increases the risk of neonatal mortality.We retrieved data from 1,815,811 liveborn infants in California from 1999 to 2003. We excluded multiple births and congenital anomalies, as well as infants with a gestational age of less than 38 w0d, or greater than 42 w6d, weeks. We used multivariable logistic regression models to adjust for demographic variables thought to confound the association.Compared to infants born at 38, 39, or 40 weeks, those born at 41 w0d to 42 w6d have a greater odds of neonatal mortality (aOR: 1.34, 95% CI, 1.08-1.65). Subdividing by gestational week, infants delivered at 41 w0d to 41 w6d showed elevated mortality relative to earlier term births (aOR: 1.37, 95% CI, 1.08-1.73). Additional analyses support this increased neonatal mortality across all normal birthweight categories.Infants born beyond 41 w0d of gestation experience greater neonatal mortality relative to term infants born between 38 w0d and 40 w6d.

The objective of the study was to examine whether the risk of perinatal complications increases with increasing gestational age among term pregnancies.This is a retrospective cohort study of low-risk women with term, singleton births in 2003 in the United States. Gestational age was subgrouped into 37, 38, 39, 40, and 41 completed weeks. Statistical comparison was performed using chi(2) test and multivariable logistic regression models, with 39 weeks' gestation as the referent.There were 2,527,766 women meeting study criteria. Compared with 39 weeks, delivery at 37 or 38 weeks had lower risk of febrile morbidity but slightly higher risk of cesarean delivery. Delivery at 40 or 41 weeks was also associated with higher overall maternal morbidity. For neonates, delivery at 40 or 41 weeks had higher risk of birthweight greater than 4500 g, neonatal injury (40 weeks: adjusted odds ratio [aOR] 1.11 [95% confidence interval (CI), 1.05-1.18]; 41 weeks: aOR 1.27 [95% CI, 1.17-1.37]) and meconium aspiration (40 weeks: aOR 1.55 [95% CI, 1.43-1.69]; 41 weeks: aOR 2.12 [95% CI, 1.91-2.35]). Delivery at 37 or 38 weeks had higher risk of hyaline membrane disease (37 weeks: aOR 3.12 [95% CI, 2.90-3.38]); 38 weeks: aOR 1.30 [95% CI, 1.19-1.43]) but lower risk of meconium aspiration.The risk of cesarean delivery and neonatal morbidity in low-risk women increases at 40 weeks and beyond, whereas the odds of serious neonatal pulmonary disease were highest at 37 weeks. Recognition of such variation in term outcomes should lead providers to avoid iatrogenic morbidity and consider interventions to prevent complications of late-term pregnancy.