Return of fertility after discontinuation of oral contraceptives: influence of age and parity.

Abstract

The authors have analyzed data on return of fertility after discontinuation of oral contraceptives and other methods of birth control among women taking part in the Oxford Family Planning Association contraceptive study. The analyses were conducted separately for nulliparous and parous women and for those aged 25 to 29 years and those aged 30 to 34 years. Return of fertility was measured as the time taken to give birth to a child. Impairment of fertility after discontinuation of oral contraceptives was very slight among parous women in both age groups. Impairment was greater among nulliparous women especially those aged 30 to 34. In this groups 48 months after cessation of contraception to plan a pregnancy 17.9% of those who had been using the pill but only 11.5% of those who had been using other methods of contraception remained undelivered. These percentages were reduced to 10.0 and 12.7% respectively 72 months after cessation of contraception. These data provide strong evidence of an interaction between the effect of age and the effect of the pill on fertility among nulliparous women. (authors)