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Background: Studies evaluating the association between prenatal ultrasounds and autism spectrum disorder (ASD) have largely produced negative results. Concern remains due to the rising identification of children with ASD and ultrasound use. Objective: To evaluate the association between prenatal ultrasound use and ASD. Methods: We used data from the Study to Explore Early Development, a multisite case‐control study of preschool‐aged children with ASD implemented during 2007–2012. We recruited cases from children receiving developmental disability services and randomly selected population controls from birth records. ASD case status was based on in‐person standardised assessments. We stratified analyses by pre‐existing maternal medical conditions and pregnancy complications associated with increased ultrasound use (ultrasound indications) and used logistic regression to model case status by increasing ultrasound counts. For pregnancies with medical record data on ultrasound timing, we conducted supplementary tests to model associations by trimester of exposure. Results: Among 1524 singleton pregnancies, ultrasound indications were more common for ASD cases than controls; respectively, for each group, no indications were reported for 45.1% and 54.2% of pregnancies, while ≥2 indications were reported for 26.1% and 18.4% of pregnancies. The percentage of pregnancies with multiple ultrasounds varied by case status and the presence of ultrasound indications. However, stratified regression models showed no association between increasing ultrasound counts and case status, either for pregnancies without (aOR 1.01, 95% CI 0.92, 1.11) or with ultrasound indications (aOR 1.01, 95% CI 0.95, 1.08). Trimester‐specific analyses using medical record data showed no association in any individual trimester. Conclusions: We found no evidence that prenatal ultrasound use increases ASD risk. Study strengths included gold‐standard assessments for ASD case classification, comparison of cases with controls, and a stratified sample to account for conditions associated both with increased prenatal ultrasound use and ASD. [ABSTRACT FROM AUTHOR]

Objectives Low gestational weight gain (GWG) in the second and third trimesters has been associated with increased risk of preterm delivery (PTD) among women with a body mass index (BMI) < 25 mg/m.sup.2. However, few studies have examined whether this association differs by the assumptions made for first trimester gain or by the reason for PTD. Methods We examined singleton pregnancies during 2000-2008 among women with a BMI < 25 kg/m.sup.2 who delivered a live-birth [greater than or equal to]28 weeks gestation (n = 12,526). Women received care within one integrated health care delivery system and began prenatal care [less than or equal to]13 weeks. Using antenatal weights measured during clinic visits, we interpolated GWG at 13 weeks gestation then estimated rate of GWG (GWG.sub.rate) during the second and third trimesters of pregnancy. We also estimated GWG.sub.rate using the common assumption of a 2-kg gain for all women by 13 weeks. We examined the covariate-adjusted association between quartiles of GWG.sub.rate and PTD (28-36 weeks gestation) using logistic regression. We also examined associations by reason for PTD [premature rupture of membranes (PROM), spontaneous labor, or medically indicated]. Results Mean GWG.sub.rate did not differ among term and preterm pregnancies regardless of interpolated or assumed GWG at 13 weeks. However, only with GWG.sub.rate estimated from interpolated GWG at 13 weeks, we observed a U-shaped relationship where odds of PTD increased with GWG.sub.rate in the lowest (OR 1.36, 95 % CI 1.10, 1.69) or highest quartile (OR 1.49, 95 % CI 1.20, 1.85) compared to GWG.sub.rate within the second quartile. Further stratifying by reason, GWG.sub.rate in the lowest quartile was positively associated with spontaneous PTD while GWG.sub.rate in the highest quartile was positively associated with PROM and medically indicated PTD. Conclusions Accurate estimates of first trimester GWG are needed. Common assumptions applied to all pregnancies may obscure the association between GWG.sub.rate and PTD. Further research is needed to fully understand whether these associations are causal or related to common antecedents., Author(s): Andrea J. Sharma[sup.1] [sup.3] , Kimberly K. Vesco[sup.2] , Joanna Bulkley[sup.2] , William M. Callaghan[sup.1] , F. Carol Bruce[sup.1] , Jenny Staab[sup.2] , Mark C. Hornbrook[sup.2] , Cynthia J. [...]

Studies report increased risk of preterm birth (PTB) among underweight and normal weight women with low gestational weight gain (GWG). However, most studies examined GWG over gestational periods that differ by term and preterm which may have biased associations because GWG rate changes over the course of pregnancy. Furthermore, few studies have specifically examined the amount and pattern of GWG early in pregnancy as a predictor of PTB. Within one integrated health care delivery system, we examined 12,526 singleton pregnancies between 2000 and 2008 among women with a body mass index 28 weeks gestation. Using self-reported pregravid weight and serial measured antenatal weights, we estimated GWG and the area under the GWG curve (AUC; an index of pattern of GWG) during the first and second trimesters of pregnancy (≤28 weeks). Using logistic regression adjusted for covariates, we examined associations between each GWG measure, categorized into quartiles, and PTB (, Author(s): Andrea J. Sharma[sup.1] [sup.3] , Kimberly K. Vesco[sup.2] , Joanna Bulkley[sup.2] , William M. Callaghan[sup.1] , F. Carol Bruce[sup.1] , Jenny Staab[sup.2] , Mark C. Hornbrook[sup.2] , Cynthia J. [...]

A short interpregnancy interval (IPI) is a risk factor for preterm delivery among women of reproductive age. As limited data exist concerning adolescents, we aimed to examine the association between short IPIs and preterm birth among adolescents using a majority of US births. Using 2007-2008 US natality data, we assessed the relationship between IPIs, Author(s): Lina M. Nerlander[sup.1] [sup.2] , William M. Callaghan[sup.1] [sup.3] , Ruben A. Smith[sup.1] [sup.3] , Wanda D. Barfield[sup.1] [sup.3] Author Affiliations: (1) Division of Reproductive Health, Centers for Disease [...]

The objective of the study was to assess if small- and large-for gestational age term infants have greater health care utilization during the first year of life. The sample included 28,215 singleton term infants (37-42 weeks) without major birth defects delivered from 1998 through 2007 and continuously enrolled at Kaiser Permanente Northwest for 12 months after delivery. Birth weight for gestational age was categorized into 3 levels: < 10th percentile (SGA), 10-90th percentile (AGA), > 90th percentile (LGA). Length of delivery hospitalization, re-hospitalizations and sick/emergency room visits were obtained from electronic records. Logistic regression models estimated associations between birth weight category and re-hospitalization. Generalized linear models estimated adjusted mean number of sick/emergency visits. Among term infants, 6.2% were SGA and 13.9% were LGA. Of infants born by cesarean section, SGA infants had 2.7 higher odds [95% 1.9, 3.8] than AGA infants of staying [greater than or equal to] 5 nights during the delivery hospitalization; of those born vaginally, SGA infants had 1.5 higher adjusted odds [95% 1.1, 2.1] of staying [greater than or equal to] 4 nights. LGA compared to AGA infants had higher odds of re-hospitalization within 2 weeks of delivery [OR 1.25, 95% CI 0.99, 1.58] and of a length of stay [greater than or equal to] 4 days during that hospitalization [OR 2.6, 95% CI 1.3, 5.0]. The adjusted mean number of sick/ emergency room visits was slightly higher in SGA (7.8) than AGA (7.5) infants (P < .05). Term infants born SGA or LGA had greater health care utilization than their counterparts, although the increase in utilization beyond the initial delivery hospitalization was small. Keywords Low birth weight * Fetal growth restriction * Large for gestational age * Macrosomia * Health care utilization, Introduction Infants born small--(SGA) and large--for-gestational age (LGA) experience greater health complications shortly after birth compared to infants born appropriate for gestational age (AGA). SGA infants experience greater risk of [...]