PRENATAL EXPOSURES AND CONGENITAL HEART-DEFECTS IN DOWN-SYNDROME INFANTS

The purpose of this study was to determine whether there are important differences in maternal and environmental prenatal risk factors betwe en liveborn Down syndrome infants with congenital heart defects and Do wn syndrome infants without heart defects. Using a case control study design, we evaluated the risk associated with maternal illness, drug i ngestion, substance usage, and chemical exposures in the home or workp lace. The period of risk selected was 3 months before and 3 months aft er the last menstrual period, because cardiac development occurs early , before the mother may become aware of her pregnancy. Because fetal s urvival in Down syndrome may be more vulnerable to various exposures, controls were selected who also had trisomy 21. Of 171 infants studied , 89 were cases with congenital heart disease, and 82 were controls wi thout heart disease. All interviews were performed by one nurse practi tioner using a structured standardized questionnaire. Cases and contro ls had similar maternal ages, family incomes, parental education level s, and contraceptive practices before pregnancy. No differences were f ound between case and control mothers for maternal illness, medication use, or consumption of caffeinated beverages, cigarettes, or alcohol. Reporting of recreational drug usage was infrequent, may reflect unde rreporting, and did not differ between cases and controls. Maternal ex posures were commonly reported for pesticides (50%), hair dyes (22%), craft paints (8%), varnishes (7%), and solvents (3.5%). However, in no ne of the categories was maternal exposure significantly more prevalen t among case mothers than among control mothers. The failure of this s tudy to identify risk factors for cardiac malformations may be attribu table to the small differences in reported frequencies reducing statis tical power or to the possibility that cardiac malformation in Down sy ndrome is a direct result of chromosomal duplication. Teratology 58:6- 12, 1998. (C) 1998 Wiley-Liss, Inc.