Periconceptional intake of vitamin supplements and risk of multiple congenital anomalies

Numerous studies have reported reduced risks for a variety of single congen ital anomaly phenotypes associated with maternal periconceptional use of vi tamin supplements containing folic acid. Here we investigated whether peric onceptional use of vitamin supplements containing folic acid by women alter ed their risk for delivering infants with multiple congenital anomalies (MC As), Data were derived from a case-control study representing deliveries (f etal deaths and infants) from 2 California counties between January 1993 an d July 1996, MCAs were defined as 2 or more congenital anomalies affecting more than one organ system or a major anomaly in combination with 2 minor a nomalies. Controls were randomly selected from nonmalformed liveborn infant s. Telephone interviews were conducted with 112 (73.7% of eligible) case an d 195 (78.0% of eligible) control mothers. Compared to women who did not us e multivitamin supplements containing folic acid in the period 3 months bef ore through 3 months after conception, women who used in this time period w ere observed to have an elevated risk to deliver fetuses or infants with MC As, odds ratio = 2.6 (95% confidence interval 1.1-6.2). This elevated risk was not substantially altered (adjusted odds ratio = 2.9 [0.8-10.3]) by adj usting for maternal race/ethnicity, education, gravidity, body mass index, alcohol consumption, and cigarette smoking, No particular organ system seem ed to be uniquely represented among the MCA fetuses and infants whose mothe rs used vitamin supplements. The observed elevated risk associated with mat ernal vitamin use is considered to be preliminary and needs to be replicate d in other populations. Am, J, Med. Genet, 93:188-193, 2000, (C) 2000 Wiley -Liss, Inc.