Outcome of pregnancies following the use of oral contraceptives.

The use of oral contraception by women doctors on the Medical Register for England and Wales in 1975 was studied and related to the outcome of their pregnancies. Nearly two thirds had used oral contraception at some time, but less than one third of their pregnancies had followed its use. Users tended to be younger at the time of the survey and to smoke in pregnancy more often. After allowing for these associations a poor outcome was just slightly more common in pregnancies occurring after OC use, particularly in conceptions occurring within a month or after a year of cessation. In contrast conceptions occurring in the 2nd or 3rd month after cessation had an unusually favourable outcome. It therefore seems likely that at least some of this weak association between oral contraception and poor outcome may be explained by factors that determine the length of time it takes to conceive. Overall it seems that any real risk to pregnancies conceived after cessation of oral contraception must be very small and outweighed by the undoubted advantages of its use.