OVULATION INDUCTION AND RISK OF NEURAL-TUBE DEFECTS

The relation between use of ovulation-inducing drugs and risk of neura l tube defects (NTDs) was studied in a case-control surveillance progr amme. The frequency of any use of such drugs during the 6 months befor e the last menstrual period or during pregnancy was 3.0% for 1034 moth ers of infants and fetuses with NTDs (cases) and 2.8% for 4081 mothers of those with other major congenital malformations (controls) (relati ve risk 1.1, 95% CI 0.8-1.7). Relative risks for clomiphene and for ho rmones were 0.8 (0.5-1.3) and 1.5 (0.7-3.4), respectively. These data suggest that use of ovulation-inducing drugs before conception does no t increase the risk of NTDs.