A population-based case-control teratologic study of acetylsalicylic acid treatments during pregnancy

Objective - To study the human teratogenic potential of two acetylsalicylic acid (ASA) drugs ASA-100 mg and ASA-500 mg. Design - Pair analysis of cases with congenital abnormalities and matched h ealthy controls. Settings - The large population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996. Subjects - 38,151 pregnant women who had newborn infants without any defect s (population control group); 22,865 case pregnant women who had newborns o r fetuses with congenital abnormalities and 812 patient controls who had of fspring with Down's syndrome. Results - In the case group 1073 (4.7%) and in the population control group 1505 (4.0%), while in the patient control group 52 (6.4%) of the pregnant women were treated with ASA. The ASA-500 was the major group because 1050 ( 4.6%) case, 1471 (3.9%) population control and 50 (6.2%) patient control pr egnant women had this treatment. The case-control pair analysis did not ind icate a higher rate of any ASA treatments during 2-3 months of gestation, i .e. in the critical period for most major congenital abnormalities. Thus al l three of our analyses, i.e. - (1) in matched case-control pairs; (2) the comparison of medically recorded ASA use in the total control group and sub jects with congenital abnormalities; (3) the comparison of the occurrence o f ASA treatment between the patient control group and subjects with congeni tal abnormalities. Conclusion - Treatment with ASA drugs studied during pregnancy did not indi cate a higher teratogenic risk to the fetus. Copyright (C) 2000 John Wiley & Sons, Ltd.