Maternal occupational exposure to polycyclic aromatic hydrocarbons: effects on gastroschisis among offspring in the National Birth Defects Prevention Study.

BACKGROUND: Exposure to polycyclic aromatic hydrocarbons (PAHs) occurs in many occupational settings. There is evidence in animal models that maternal exposure to PAHs during pregnancy is associated with gastroschisis in offspring; however, to our knowledge, no human studies examining this association have been conducted. OBJECTIVE: Our goal was to conduct a case-control study assessing the association between estimated maternal occupational exposure to PAHs and gastroschisis in offspring. METHODS: Data from gastroschisis cases and control infants were obtained from the population-based National Birth Defects Prevention Study for the period 1997-2002. Exposure to PAHs was assigned by industrial hygienist consensus, based on self-reported maternal occupational histories from 1 month before conception through the third month of pregnancy. Logistic regression was used to determine the association between estimated occupational PAH exposure and gastroschisis among children whose mothers were employed for at least 1 month during the month before conception through the third month of pregnancy. RESULTS: The prevalence of estimated occupational PAH exposure was 9.0% in case mothers (27 of 299) and 3.6% in control mothers (107 of 2,993). Logistic regression analyses indicated a significant association between occupational PAHs and gastroschisis among mothers ≥ 20 years of age [odds ratio (OR) = 2.53; 95% confidence interval (CI): 1.27, 5.04] after adjusting for maternal body mass index, education, gestational diabetes, and smoking. This association was not seen in mothers < 20 years (OR = 1.14; 95% CI: 0.55, 2.33), which is notable because although young maternal age is the strongest known risk factor for gastroschisis, most cases are born to mothers ≥ 20 years. CONCLUSION: Our findings indicate an association between occupational exposure to PAHs among mothers who are ≥ 20 years and gastroschisis. These results contribute to a body of evidence that PAHs may be teratogenic.

Influencing clinical practice regarding the use of antiepileptic medications during pregnancy: modeling the potential impact on the prevalences of spina bifida and cleft palate in the United States.

Selected antiepileptic drugs (AEDs) increase the risk of birth defects. To assess the impact of influencing AED prescribing practices on spina bifida and cleft palate we searched the literature for estimates of the association between valproic acid or carbamazepine use during pregnancy and these defects and summarized the associations using meta-analyses. We estimated distributions of the prevalence of valproic acid and carbamazepine use among women of childbearing age based on analyses of four data sets. We estimated the attributable fractions and the number of children born with each defect that could be prevented annually in the United States if valproic acid and carbamazepine were not used during pregnancy. The summary odds ratio estimate for the association between valproic acid and spina bifida was 11.9 (95% uncertainty interval (UI): 4.0-21.2); for valproic acid and cleft palate 5.8 (95% UI: 3.3-9.5); for carbamazepine and spina bifida 3.6 (95% UI: 1.3-7.8); and for carbamazepine and cleft palate 2.4 (95% UI: 1.1-4.5) in the United States. Approximately 40 infants (95% UI: 10-100) with spina bifida and 35 infants (95% UI: 10-70) with cleft palate could be born without these defects each year if valproic acid were not used during pregnancy; 5 infants (95% UI: 0-15) with spina bifida and 5 infants (95% UI: 0-15) with cleft palate could be born without these defects each year if carbamazepine were not used during pregnancy. This modeling approach could be extended to other medications to estimate the impact of translating pharmacoepidemiologic data to evidence-based prenatal care practice.

Epidemiology of fertility treatment use among U.S. women with liveborn infants, 1997-2004.

OBJECTIVE: This study assessed reported use of assisted reproductive technology (ART) and other (non-ART) fertility treatments among a population-based sample and examined factors related to use. METHODS: The data for this study were collected as part of the National Birth Defects Prevention Study (NBDPS), limited to women from the control group who delivered liveborn infants with no major birth defects. We described prevalence of the use of ART and clomiphene citrate (the most commonly used non-ART treatment) by demographic and lifestyle factors and examined associations among use of fertility treatments and pregnancy outcomes, timing of prenatal care initiation, and use of prenatal testing technologies. RESULTS: Overall, 4.2% of women reported any type of maternal fertility treatment use; 1.0% reported ART use, 1.6% reported clomiphene citrate use without ART, and 1.7% reported other fertility treatments. Women who reported any fertility treatment type were more likely than women with an unassisted conception to be non-Hispanic white, >30 years of age, and more highly educated. Overall, women who reported ART use were more likely than women who reported unassisted pregnancy to have an amniocentesis; however, this association was no longer evident after adjustment for maternal age. CONCLUSIONS: Fertility treatment use and type of treatment vary by maternal characteristics. This information may be useful to inform a broad maternal and child health audience about the growing use of fertility treatments, including who is using the treatments and the choices they are making about prenatal care.