Expectations of assisted conception for infertility.

OBJECTIVE: To provide reliable prognostic information for couples seeking assisted conception. DESIGN: Analysis of four years' practice (1988-91). SETTING: Private university service linked with NHS reproductive medicine services. PATIENTS: 804 couples with various causes of subfertility, median duration five years, median age of women 34 years. INTERVENTIONS: 1280 completed cycles: 950 in vitro fertilisation, 144 gamete intrafallopian transfer, and 186 intrauterine insemination and superovulation. MAIN OUTCOME MEASURES: Pregnancy and birth rates per cycle and cumulative pregnancy and take home baby rates per couple. RESULTS: In women under 40 years and men with normal sperm, whatever the cause of infertility, results with in vitro fertilisation improved steadily reaching a pregnancy rate per cycle of 30% (95% confidence interval 26% to 35%) during 1990-1 and birth rate per cycle of 29% (23% to 35%) in 1990. Pregnancy and birth rates for gamete intrafallopian transfer were 36% (28% to 44%) and 26% (17% to 37%) and for intrauterine insemination 18% (12% to 24%) and 16% (10% to 22%). After six cycles cumulative probability of pregnancy was 82% and cumulative take home baby rate 70%. Considering only in vitro fertilisation and gamete intrafallopian transfer after four cycles the pregnancy rate was 78% (66% to 91%). CONCLUSIONS: Conception is less likely in women over 40 and men with sperm dysfunction. For other couples the prognosis for a live birth is at least as good as for fertile couples if they persist with treatment.