[1190.3] Risk of Congenital Heart Defects in the Offspring of Mothers Who Smoke Cigarettes During Pregnancy: A Population-Based Case-Control Study of Washington State Birth Certificates and Hospital Discharge Data from 1989-2011

Patrick M. Sullivan, Leslie Dervan, Sheridan Reiger, Stephen M. Schwartz. Pediatric Cardiology, Seattle Children's Hospital, Seattle, WA; Pediatric Critical Care, Seattle Children's Hospital, Seattle, WA; Epidemiology, University of Washington School of Public Health, Seattle, WA.

BACKGROUND: Congenital heart defects (CHDs) are among the most common, costly, and deadly congenital anomalies. While maternal cigarette smoking during pregnancy has been linked to multiple congenital anomalies, its association with CHDs is not well established.
OBJECTIVE: We conducted the largest population-based study to date measuring the association between maternal smoking during pregnancy and the occurrence of CHDs with attention to dose-dependence and effect modification by other maternal risk factors.
DESIGN/METHODS: This retrospective case-control study used WA State birth certificate data from 1989-2011 and ICD-9 codes in hospital discharge records to identify CHD cases and controls and to determine maternal smoking status. We used stratified Mantel-Haenszel adjusted OR estimates to compare maternal smoking status during the 1st trimester of pregnancy among 14,128 cases, both overall and by phenotype, and 62,274 randomly selected controls matched on birth year. We measured dose-specific ORs by daily number of cigarettes and evaluated effect modification by selected maternal risk factors.
RESULTS: Offspring of smoking mothers were more likely to be born with a CHD (OR: 1.19 [1.13-1.26]). Smoking was specifically associated with pulmonary valve anomalies (OR: 1.53 [1.27-1.84]), pulmonary artery anomalies (OR: 1.69 [1.45-1.97]), and isolated atrial septal defects (OR: 1.35 [1.23-1.49]). The association between maternal smoking and CHDs was dose-dependent and stronger when mothers gave birth at 35 years of age or older (see table).

ORs and 95% CIs for the association between first trimester maternal smoking and occurrence of congenital heart defects in singleton births stratified by daily exposure dose and maternal age, Washington State 1989-2011
Any Smoking1-10 Cigarettes11-20 Cigarettes>20 Cigarettes
All Subjects1.19 (1.13-1.25)1.15 (1.08-1.22)1.25 (1.13-1.39)1.56 (1.08-2.00)
Maternal Age <351.16 (1.10-1.23)1.14 (1.06-1.22)1.19 (1.06-1.33)1.48 (1.03-2.09)
Maternal Age 35+1.61 (1.36-1.91)1.44 (1.15-1.79)1.85 (1.37-2.48)2.14 (0.89-4.85)

CONCLUSIONS: Maternal cigarette smoking during pregnancy is a modest independent risk factor for select CHD phenotypes. New findings include a dose-dependence of the association and modification by advanced maternal age.
First Author is a Fellow in Training

Session: Platform Session: Strategies for Prevention in Newborn Populations (8:00 AM - 10:00 AM)
Date/Time: Saturday, May 3, 2014 - 8:30 AM
Room: West 110 - Vancouver Convention Centre
Course Code: 1190


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