Congenital limb reduction deformities and use of oral contraceptives.

A study of congenital limb deficiencies in two Australian states indicated that use of an oral contraceptive during pregnancy by the mother was associated with an increased risk of limb defect in the child. The study included mothers of 155 children born with absence or reduction of the major long bones during a 12-year period from 1970 onward; 274 mothers with births of normal infants, matched for date of birth and area of residence, made up the control group. Compared with control infants, the case infants were more likely to have been conceived while the mother was using an oral contraceptive, especially when the deformity was a transverse or amputation type. It is too early in our state of knowledge of teratogenic mechanisms to exclude the possible existence of a biologic mechanism that would explain this statistical association.