The better prognosis in secondary infertility is associated with a higher proportion of ovulation disorders.

To determine the reason for the higher pregnancy rate in couples with secondary infertility, the authors compared 237 infertile couples who had a previous pregnancy in the current partnership (secondary infertility) with 135 infertile couples in whom the woman had been pregnant only in a previous partnership and 925 couples with primary infertility. Couples with secondary infertility had the highest proportion of ovulation disorders (36%); these couples with secondary infertility and an ovulation disorder had the shortest duration of infertility (26 months). Cumulative pregnancy rates at 36 months were 56% in secondary fertility, 44% in primary infertility, and 42% in pregnancy in a previous partnership (P = 0.001). In this study, the better prognosis in secondary infertility may be related to the higher proportion of couples with ovulation disorders, who had a shorter duration of infertility. Abortion rates in the earlier pregnancies with current or previous partners were 37% and 30%, respectively; after the period of infertility, the abortion rates were 14% and 12%, respectively.