The outcome of pregnancy in former oral contraceptive users.

As part of a continuing major prospective survey, the outcome of 5530 pregnancies in former oral contraceptive (pill) users was compared with the outcome of 11 009 pregnancies in the control series of women who had never used the pill. In former pill users there was a significantly higher induced abortion rate. There was no increase in the reported spontaneous abortion rate, and there is evidence to suggest that the true spontaneous abortion rate may be materially lower in former pill users. The previous use of oral contraceptives appeared to have no adverse effect on subsequent births.