Exploring the seasonality of birth defects in the New York State Congenital Malformations Registry.

Background: Examining seasonal patterns of birth defects may help to identify environmental risk factors. Because the teratogenic window for most birth defects is during gestational weeks 3 to 8, investigating exposures closer to the timing of conception is important. However, studies are usually based on month of birth, which is not the biologically relevant exposure period and does not account for differences in gestational length.

Maternal bronchodilator use and the risk of orofacial clefts.

Background: Few epidemiological studies have explored the relationship between orofacial clefts and bronchodilators. We assessed whether mothers who used bronchodilators during early pregnancy were at an increased risk of delivering infants with orofacial clefts.

Methods: We used National Birth Defects Prevention Study case-control data from mothers of 2711 infants with orofacial clefts and 6482 mothers of live born infants without birth defects, delivered during 1997 through 2005.

Characteristics of pregnant illicit drug users and associations between cannabis use and perinatal outcome in a population-based study.

Background: According to the 2004 National Survey on Drug Use and Health, 4.6% of American women reported use of an illicit drug during pregnancy. Previous studies on illicit drug use during pregnancy and perinatal outcomes showed inconsistent results.

Residential mobility during pregnancy and the potential for ambient air pollution exposure misclassification.

Studies of environmental exposures and adverse birth outcomes often rely on maternal address at birth obtained from the birth certificate to classify exposure. Although the gestational age of interest is often early pregnancy, maternal addresses are not available for women who move during pregnancy when using maternal addresses abstracted from birth certificates. The aim of this study was to explore the extent of ambient air pollutant exposure misclassification due to maternal residential mobility during pregnancy among the subgroup of a New York birth cohort.

Control selection and participation in an ongoing, population-based, case-control study of birth defects: the National Birth Defects Prevention Study.

To evaluate the representativeness of controls in an ongoing, population-based, case-control study of birth defects in 10 centers across the United States, researchers compared 1997-2003 birth certificate data linked to selected controls (n = 6,681) and control participants (n = 4,395) with those from their base populations (n = 2,468,697). Researchers analyzed differences in population characteristics (e.g.

Antihypertensive medication use during pregnancy and the risk of cardiovascular malformations.

We used data from the National Birth Defects Prevention Study, a population-based, case-control study, to examine whether previously reported associations between antihypertensive medications and cardiovascular malformations could be confirmed and to explore whether new associations might be identified. Cases (n=5021) were ascertained through birth defects surveillance systems from 1997 through 2003 in 10 US states. Controls (n=4796) were live births without birth defects selected randomly from birth certificates or hospital discharge listings in the same geographic regions.

Maternal thyroid disease, thyroid medication use, and selected birth defects in the National Birth Defects Prevention Study.

Background: Although thyroid disorders are present in approximately 3% of pregnant women, little is known about the association between maternal thyroid disease and birth defects.

Methods: We assessed the association between maternal thyroid disease, thyroid medication use, and 38 types of birth defects among 14,067 cases and 5875 controls in the National Birth Defects Prevention Study, a multisite, population-based, case-control study. Infants in this study were born between October 1997 and December 2004.

Maternal periconceptional illicit drug use and the risk of congenital malformations.

Background: In 2004, the Survey on Drug Use and Health showed that 5% of American women reported use of an illicit drug during pregnancy. The results of studies determining the association between periconceptional illicit drug use and birth defects have been inconsistent.

Methods: We analyzed data from the National Birth Defects Prevention Study, a case-control study of major birth defects, and assessed all birth defects categories in which there were at least 250 interviewed case mothers.

Maternal hypertension, antihypertensive medication use, and the risk of severe hypospadias.

Background: Hypertensive disorders occur in an estimated 5-10% of pregnancies, but few studies have examined birth defects in relation to high blood pressure and antihypertensive medication use. The objective of this study was to investigate the relationship between high blood pressure, antihypertensive medication use, and severe hypospadias.

Methods: We used data from the National Birth Defects Prevention Study, a population-based, multicenter, case-control study of birth defects to assess risks for severe hypospadias in relation to self-reported high blood pressure and prenatal exposures to antihypertensive drugs in 758 male infants with severe hypospadias and 2,058 male controls born between 1997 and 2002.

Epidemiology of bladder and cloacal exstrophies in New York State, 1983-1999.

Background: Bladder exstrophy (BE) and cloacal exstrophy (CE) are rare birth defects that have been reported to occur in 1:30,000-50,000 and 1:200,000-400,000 live births. Disagreement exists as to whether they comprise two distinct disorders or are part of a spectrum. We examined epidemiologic trends and risk factors for BE and CE in a large population-based dataset.

Risk factors for isolated biliary atresia, National Birth Defects Prevention Study, 1997-2002.

Biliary atresia is a rare birth defect that affects 1 in 12,000 to 1 in 19,500 live births. We used data from the National Birth Defects Prevention Study, a multistate case-control study, to identify potential risk factors for isolated biliary atresia (no additional unrelated major birth defects diagnosed). Infants were identified from eight states from 1997 to 2002, with clinical information abstracted from medical records.

The epidemiology of extrahepatic biliary atresia in New York State, 1983-98.

The aetiology of biliary atresia, the leading cause of neonatal extrahepatic jaundice and the main indication for liver transplantation in children, is unknown. Recent research has focused on an infectious aetiology and the development of viral models in animals. The few published epidemiological studies report conflicting results for seasonal, geographical, and racial variations in incidence.