The effect of induced abortion on subsequent fertility

Abstract

To investigate the effect of induced abortion on subsequent fertility. 1. Prospective cohort study of women who had an unplanned pregnancy at recruitment. 2. Retrospective study of women who had a planned pregnancy at recruitment. Joint Royal College of General Practitioners/Royal College of Obstetricians and Gynaecologists study based in general practice in England, Scotland and Wales, between 1976 and 1987. 1. Prospective study: Four hundred and thirty-three women with a recruitment unplanned pregnancy ending in induced abortion (abortion group) and 1035 women with a recruitment unplanned pregnancy which ended naturally (nonabortion group). All subsequently had a planned pregnancy, or were known to be trying to conceive at some point during the follow-up. 2. Retrospective study: Nine thousand two hundred and ninety-nine women who presented at recruitment with a planned pregnancy. The women's estimated length of planning time, expressed as a fertility rate ratio. Induced abortion was not related to future fertility. In the prospective study, the fertility rate ratio (FRR) of the abortion group relative to the nonabortion group was 0.94 (95% CI 0.83 to 1.07, P = 0.37). This result was supported by the retrospective study, which again showed no important difference between the two groups. Induced abortion does not appear to have an important effect on future fertility.