Letter: Oral contraceptives and congenital limb-reduction defects.

Abstract

The author belives that the congenital limb defects observed and reported in a previous paper by Janerich and others were due to a secondary relation and not causally related to the use of oral contraceptives. In 6 reported cases mothers of affected infants became pregnant while still using oral contraceptives in the prescribed manner. This is in conflict with the writer's experience. In 149 unplanned pregnancies he found that 95 (64%) were due to an incorrect use of the pill. Limb defect due to use of the pill in early pregnancy should also be caused by instance of improver use of the pill with resulting pregnancy. This has not been observed. Reduction in the pills' expected antifertility effect because of the mothers' unusually fertile condition was considered the cause of the limb defects. In the writer's opinion a more likely explanation is that the action of the oral contraceptives in these cases has been inhibited by the concurrent use of their drugs. Suspicion of teratogenicity must therefore be associated with the other drugs.