Asthma Medication Use and Risk of Birth Defects: National Birth Defects Prevention Study, 1997-2011.

BACKGROUND: Evidence regarding associations between maternal asthma medication use and birth defects is mixed. OBJECTIVE: Estimate associations between asthma medciation use and 52 birth defects using National Birth Defects Prevention Study data from 1997 to 2011. METHODS: We compared self-reported maternal asthma medication use for 28,481 birth defect cases and 10,894 nonmalformed controls. We calculated adjusted odds ratios (95% CIs) to estimate the risk of birth defects associated with early pregnancy asthma medication use (the month before through the third month of pregnancy), controlling for maternal age, race/ethnicity, body mass index, smoking, folic acid-containing supplement use, and parity. We calculated risks by medication groupings: bronchodilators, anti-inflammatories, and both. RESULTS: Overall, 1304 (5%) case and 449 (4%) control women reported early pregnancy asthma medication use. We observed an association between asthma medication use and longitudinal limb deficiency (1.81; 95% CI, 1.27-2.58). Early pregnancy bronchodilator-only use was associated with cleft palate (1.50; 95% CI, 1.11-2.02), cleft lip (1.58; 95% CI, 1.12-2.23), longitudinal limb deficiency (2.35; 95% CI, 1.55-3.54), and truncus arteriosus (2.48; 95% CI, 1.13-5.42). Although early pregnancy anti-inflammatory-only use was not associated with the birth defects studied, use of both medications was associated with biliary atresia (3.60; 95% CI, 1.55-8.35) and pulmonary atresia (2.50; 95% CI, 1.09-5.78). CONCLUSIONS: Consistent with previous National Birth Defects Prevention Study analyses, asthma medication use was not associated with most birth defects examined, but we observed modest risks for bronchodilator use and several birth defects. Our findings support maintaining adequate asthma treatment during pregnancy, because early pregnancy asthma exacerbations have been associated with adverse birth outcomes, including birth defects.

Tetanus, diphtheria, and pertussis vaccine (Tdap) in pregnancy and risk of major birth defects in the offspring.

BACKGROUND: The tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine is recommended during pregnancy to protect newborns against pertussis infection in the months prior to their primary pertussis vaccination. Although research on the safety of the vaccine has been reassuring, most previous studies have considered major malformations as a single outcome, and have not examined potential risks for specific malformations. METHODS: Using data from the Slone Epidemiology Center Birth Defects Study collected between 2006 and 2015, we identified exposures to Tdap vaccine in both early and late pregnancy and examined potential risks for specific malformations. We used logistic regression models to calculate propensity score-adjusted odds ratios (aORs) and 95% confidence intervals (CIs). RESULTS: We identified 2,357 women exposed to Tdap during pregnancy. For first trimester exposures, the risk estimate for malformations overall was 1.0 (0.7, 1.5). We had power to examine nine specific malformations and found adjusted odds ratios ranging from 0.7 to 1.3, none of which had confidence intervals that excluded 1.0. For second or third trimester exposures, we examined 15 malformations with potential late pregnancy etiology, and calculated adjusted risk estimates for nine of these. Risk estimates ranged from 0.5 to 1.9, with no lower confidence bounds that excluded 1.0. CONCLUSIONS: We observed no evidence of appreciable risks for selected specific major malformations associated with Tdap vaccine exposure during early or late pregnancy. As pertussis remains a public health concern and Tdap vaccination levels in pregnancy remain below desired levels, these data provide further reassurance regarding the current recommendations for Tdap vaccination in pregnancy.

Risk of Stillbirth for Fetuses With Specific Birth Defects.

OBJECTIVE: To estimate the risk of stillbirth (fetal death at 20 weeks of gestation or more) associated with specific birth defects. METHODS: We identified a population-based retrospective cohort of neonates and fetuses with selected major birth defects and without known or strongly suspected chromosomal or single-gene disorders from active birth defects surveillance programs in nine states. Abstracted medical records were reviewed by clinical geneticists to confirm and classify all birth defects and birth defect patterns. We estimated risks of stillbirth specific to birth defects among pregnancies overall and among those with isolated birth defects; potential bias owing to elective termination was quantified. RESULTS: Of 19,170 eligible neonates and fetuses with birth defects, 17,224 were liveborn, 852 stillborn, and 672 electively terminated. Overall, stillbirth risks ranged from 11 per 1,000 fetuses with bladder exstrophy (95% CI 0-57) to 490 per 1,000 fetuses with limb-body-wall complex (95% CI 368-623). Among those with isolated birth defects not affecting major vital organs, elevated risks (per 1,000 fetuses) were observed for cleft lip with cleft palate (10; 95% CI 7-15), transverse limb deficiencies (26; 95% CI 16-39), longitudinal limb deficiencies (11; 95% CI 3-28), and limb defects due to amniotic bands (110; 95% CI 68-171). Quantified bias analysis suggests that failure to account for terminations may lead to up to fourfold underestimation of the observed risks of stillbirth for sacral agenesis (13/1,000; 95% CI 2-47), isolated spina bifida (24/1,000; 95% CI 17-34), and holoprosencephaly (30/1,000; 95% CI 10-68). CONCLUSION: Birth defect-specific stillbirth risk was high compared with the U.S. stillbirth risk (6/1,000 fetuses), even for isolated cases of oral clefts and limb defects; elective termination may appreciably bias some estimates. These data can inform clinical care and counseling after prenatal diagnosis.

Oseltamivir exposure in pregnancy and the risk of specific birth defects.

BACKGROUND: Influenza during pregnancy contributes to maternal morbidity and mortality. Neuraminidase inhibitors, including oseltamivir, are recommended for treating women with influenza during pregnancy. METHODS: Data from the Slone Birth Defects Study from 2009 to 2015 were used to investigate associations between oseltamivir and specific birth defects. We classified exposures according to timing in pregnancy and examined 52 and 16 defects with early and potential late pregnancy etiology, respectively; we calculated crude odds ratios (ORs) and 95% confidence intervals (CIs) for defects with three or more exposures. RESULTS: Among 8,379 cases and 4,190 nonmalformed controls, we identified 79 and 42 oseltamivir exposures, respectively. The majority of defects had no exposures. ORs were elevated for several defects, but the CI excluded the null only for intestinal malrotation (OR: 10.7 [1.8, 45.2]; three exposures). CONCLUSIONS: Largely null findings for specific defects are reassuring. The association with intestinal malrotation, while unstable, warrants further investigation.

Risk factors for congenital microcephaly in the pre-Zika era.

BACKGROUND: The Zika epidemic has brought increased attention to congenital microcephaly as a birth outcome. However, little is known about risks for microcephaly unrelated to Zika. METHODS: Using data from the Slone Epidemiology Center Birth Defects Study from 1993 to 2015, we identified 57 cases of microcephaly alone ("isolated") and 109 cases of microcephaly that included other major birth defects ("non-isolated"), and considered a large number of potential risk factors including demographic characteristics, illnesses, and medications used during pregnancy. Where numbers permitted, we used logistic regression models to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). RESULTS: Substantial differences in risk factors were observed for isolated versus non-isolated microcephaly. For isolated microcephaly, risk estimates were elevated for mothers of non-Hispanic, non-White race/ethnicity, and underweight pre-pregnancy body mass index (BMI). The risk for exposure anytime in pregnancy to acetaminophen was null; in contrast, the aOR for NSAIDs was 2.4 (95% CI: 1.3-4.2). This association was weakened (but not eliminated) after excluding those exposed to opioids or illicit drugs, and risk was not present among those reporting less frequent exposures. For non-isolated microcephaly, elevated risk estimates were found for urinary tract infection. CONCLUSIONS: Risk factors differed for isolated and non-isolated microcephaly. While some findings support previously reported associations, (e.g., smoking, alcohol, underweight BMI), we also identified risk factors not previously described, notably NSAID use for isolated microcephaly and urinary tract infection for non-isolated microcephaly; however, these results should be viewed as hypothesis generating.

An application of data mining to identify potential risk factors for anophthalmia and microphthalmia.

BACKGROUND: We examined a large number of variables to generate new hypotheses regarding a wider range of risk factors for anophthalmia/microphthalmia using data mining. METHODS: Data were from the National Birth Defects Prevention Study, a multicentre, case-control study from 10 centres in the United States. There were 134 cases of "isolated" and 87 "nonisolated" (with other major birth defects) of anophthalmia/microphthalmia and 11 052 nonmalformed controls with delivery dates October 1997-December 2011. Using random forest, a data mining procedure, we compared the two case types with controls for 201 variables. Variables considered important ranked by random forest were included in a multivariable logistic regression model to estimate odds ratios and 95% confidence intervals. RESULTS: Predictors for isolated cases included paternal race/ethnicity, maternal intake of certain nutrients and foods, and childhood health problems in relatives. Using regression, inverse associations were observed with greater maternal education and with increasing intake of folate and potatoes. Odds were slightly higher with greater paternal education, for increased intake of carbohydrates and beans, and if relatives had a childhood health problem. For nonisolated cases, predictors included paternal race/ethnicity, maternal intake of certain nutrients, and smoking in the home the month before conception. Odds were higher for Hispanic fathers and smoking in the home and NSAID use the month before conception. CONCLUSIONS: Results appear to support previously hypothesised risk factors, socio-economic status, NSAID use, and inadequate folate intake, and potentially provide new areas such as passive smoking pre-pregnancy, and paternal education and ethnicity, to explore for further understanding of anophthalmia/microphthalmia.

Metformin in the first trimester and risks for specific birth defects in the National Birth Defects Prevention Study.

BACKGROUND: We assessed associations between first-trimester metformin use for pregestational diabetes and specific major birth defects. METHODS: We compared risks associated with first-trimester metformin use by diabetic women to nondiabetic women on no diabetes medication; we calculated crude odds ratios by exact logistic regression and adjusted by inverse probability weighting. Confounding by diabetes was assessed by comparing risks for metformin-exposed diabetic women to those for insulin-exposed diabetics and nondiabetics treated with metformin for subfertililty. RESULTS: Among 9,279 nonmalformed controls and 24,375 malformed cases, diabetics who used metformin (with or without insulin) had increased adjusted odds ratios (aORs) for several birth defects associated with diabetes. However, women treated with metformin for subfertility had aORs similar to or lower than those for diabetic metformin users, and many approximated the null. For atrial septal defect secundum, anorectal defects, and limb reduction defects, the estimates for metformin when used for subfertility were 2-3-fold. CONCLUSION: While metformin use for diabetes was associated with an increased risk of many birth defects, when metformin was used for subfertility most defects had aORs that approximated the null, while only three defects had modestly increased aORs, two of which had lower confidence bounds that included the null. Our study does not suggest that metformin poses an appreciable risk for major birth defects, but further studies are necessary.

Tdap Vaccination Coverage During Pregnancy - Selected Sites, United States, 2006-2015.

Tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine is recommended during the third trimester of each pregnancy to provide protection to newborns, who are at risk for pertussis-related morbidity and mortality (1). As part of its case-control surveillance study of medications and birth defects, the Birth Defects Study of the Slone Epidemiology Center at Boston University (the Birth Defects Study) has recorded data on vaccinations received during pregnancy since 2006. Among 5,606 mothers of infants without structural birth defects in this population (control group), <1% had received Tdap vaccine before 2009. By 2012, the percentage of mothers of infants in the control group (control infants) who had received Tdap increased to approximately 9%, and then in 2013 and continuing through 2015, increased markedly, to 28% and 54%, respectively. As the prevalence of maternal Tdap vaccination increased, so did the proportion of pregnant women who received Tdap in the third trimester, as recommended (94%-100% from 2010 to 2015). The vast majority of Tdap vaccinations (96%) were received in a traditional health care setting (e.g., the office of the woman's obstetrician or primary care physician or her prenatal clinic). Increasing vaccination coverage during pregnancy could help reduce the impact of pertussis on infant morbidity and mortality.

Influenza Vaccination Coverage During Pregnancy - Selected Sites, United States, 2005-06 Through 2013-14 Influenza Vaccine Seasons.

Seasonal influenza vaccine is recommended for all pregnant women because of their increased risk for influenza-associated complications. In addition, receipt of influenza vaccine by women during pregnancy has been shown to protect their infants for several months after birth (1). As part of its case-control surveillance study of medications and birth defects, the Birth Defects Study of the Slone Epidemiology Center at Boston University has recorded data on vaccinations received during pregnancy since the 2005-06 influenza vaccination season. Among the 5,318 mothers of infants without major structural birth defects (control newborns) in this population, seasonal influenza vaccination coverage was approximately 20% in the seasons preceding the 2009-10 pandemic H1N1 (pH1N1) influenza season. During the 2009-10 influenza vaccination season, influenza vaccination coverage among pregnant women increased to 33%, and has increased modestly since then, to 41% during the 2013-14 season. Among pregnant women who received influenza vaccine during the 2013-14 season, 80% reported receiving their vaccine in a traditional health care setting, (e.g., the office of their obstetrician or primary care physician or their prenatal clinic) and 20% received it in a work/school, pharmacy/supermarket, or government setting. Incorporating routine administration of seasonal influenza vaccination into the management of pregnant women by their health care providers might increase coverage with this important public health intervention.

Safety of the 2011-12, 2012-13, and 2013-14 seasonal influenza vaccines in pregnancy: Preterm delivery and specific malformations, a study from the case-control arm of VAMPSS.

BACKGROUND: Pregnant women have higher risks of influenza complications, but vaccine coverage is incomplete. Because concern about fetal harm limits uptake, we investigated risks for preterm delivery (PTD) and specific birth defects following vaccination in the 2011-12 through 2013-14 influenza seasons. METHODS: We used data from the Slone Epidemiology Center's Birth Defects Study. For PTD, propensity score-adjusted time-varying hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for exposure anytime in pregnancy and for each trimester. For 42 specific major birth defects or birth defect categories, propensity score-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated. RESULTS: For PTD (1803 fullterm deliveries, 107 PTD for all seasons combined), an elevated adjusted risk was observed for only the 2nd trimester of the 2011-12 season (HR=2.60, 95% CI 1.21, 5.61) - a reduction in gestational length of <2days. For the 42 specific defects or categories of defects (2866 cases, 1411 controls for all seasons combined) most adjusted risks were close to 1.0; the highest was 2.38 for omphalocele and the lowest was 0.50 for atrioventricular canal defects. None had lower confidence bounds >1.0. For each season separately, only one elevated OR had a lower 95% CI >1.0: omphalocele in 2011-12 (OR=5.19, 95% CI 1.44, 18.7). CONCLUSIONS: Our results regarding risks for PTD and birth defects are generally reassuring. The few risks that were observed are compatible with chance, but warrant testing in other data. Given that vaccine components and manufacturing processes vary, continuing studies are needed to evaluate risks and safety of each season's vaccine and specific products.

Vasoactive exposures during pregnancy and risk of microtia.

BACKGROUND: Little is known about the etiology of nonsyndromic microtia. This study investigated the hypothesis that microtia is caused by vascular disruption. METHODS: The study analyzed data from the population-based National Birth Defects Prevention Study (NBDPS) for deliveries between 1997 and 2005. Four hundred eleven nonsyndromic cases of microtia, with or without additional defects, were compared to 6560 nonmalformed infants with respect to maternal exposures to vasoactive medications and smoking during the periconceptional period and conditions that have previously been associated with vascular events (multiple gestation, maternal history of type 1, type 2, or gestational diabetes, and hypertension). Odds ratios (ORs) were estimated with multivariable models, controlling for the effects of race/ethnicity, education, periconceptional folic acid use, and study center. RESULTS: Risk estimates for vasoactive medications and smoking were not meaningfully increased. Maternal type 1/2 diabetes was diagnosed before or during the index pregnancy in 4% and 1% of cases, respectively, compared to 1% and 0.05% of controls; the adjusted OR for these two groups combined was 7.2 (95% confidence interval [CI], 3.9-13.1). Gestational diabetes was observed for 9% of cases and 6% of controls; the OR was moderately elevated (OR, 1.4; 95% CI, 0.9-2.0). ORs were also increased for multiple gestations (OR, 2.5; 95% CI, 1.5-4.2) and pre-existing hypertension (OR, 1.6; 95% CI, 1.0-2.5). CONCLUSIONS: Because ORs were only elevated for diabetes and not for vasoactive exposures or other potential vascular events, findings suggest that some microtia occurrences may be part of the diabetic embryopathy rather than manifestations of vascular disruption. Birth Defects Research (Part A), 2013. © 2012 Wiley Periodicals, Inc.

Classification of the myelodysplastic syndrome in a national registry of recently diagnosed patients.

BACKGROUND: It is not known to what extent the WHO classification scheme for MDS has been adopted in clinical practice. METHODS: We reviewed the medical records of 200 newly diagnosed MDS patients enrolled in our national registry during the years 2006-2008 to determine the scheme used. RESULTS: Clear WHO subtypes were recorded for 45.0% of patients, compared to 5.5% for FAB subtypes; 28.0% had MDS documented but without WHO or FAB subtype, and for 22.5%, the schema was unclear. CONCLUSION: Although many MDS patients do not have a subtype or schema documented, when they do, the WHO system is widely used.