Associations between maternal fever and influenza and congenital heart defects.

Objective: To examine associations between maternal reports of prenatal fever or influenza and congenital heart defects (CHDs), and to evaluate whether those associations varied with antipyretic use.

Methods: We analyzed case infants with CHD (n = 2361) and control infants without CHD (n = 3435) from the Baltimore-Washington Infant Study (1981-1989). Participating mothers were asked whether they experienced a "fever of 101°F or higher," had "influenza (flu)," or used an antipyretic agent (ie, acetaminophen, salicylate, or nonsteroidal anti-inflammatory drug) during the period extending from 3 months before pregnancy through the end of the third month of pregnancy. We used logistic regression to compute ORs and 95% CIs while controlling for potential confounders.

Results: There were significant associations between fever and influenza and specific CHDs, namely right-sided obstructive defects (fever: OR, 2.04; 95% CI, 1.27 to 3.27; influenza: OR, 1.75; 95% CI, 1.16 to 2.62) and atrioventricular septal defects in infants with Down syndrome (fever: OR, 1.92; 95% CI, 1.10 to 3.38; influenza: OR, 1.66; 95% CI, 1.04 to 2.63). Maternal antipyretic use in the setting of fever or influenza tended to decrease these associations.

Conclusions: Prenatal maternal fever or influenza may be associated with right-sided obstructive lesions in all infants and with atrioventricular septal defects in infants with Down syndrome. The use of antipyretics might attenuate such associations.