Fecundity of infertile women with minimal or mild endometriosis and women with unexplained infertility. The Canadian Collaborative Group on Endometriosis.

OBJECTIVE: To assess whether infertile women with minimal or mild endometriosis have lower fecundity than women with unexplained infertility.
DESIGN: Prospective cohort study.
SETTING: Twenty-three infertility clinics across Canada. PATIENT(S): Three hundred thirty-one infertile women aged 20-39 years. INTERVENTION(S): Diagnostic laparoscopy for infertility. Infertile women with minimal or mild endometriosis (n = 168) were compared with women with unexplained infertility (n = 263). Both groups were managed expectantly. The women were followed up for 36 weeks after the laparoscopy or, for those who became pregnant, for up to 20 weeks of the pregnancy. MAIN OUTCOME MEASURE(S): Fecundity refers to the probability of becoming pregnant in the first 36 weeks after laparoscopy and carrying the pregnancy for > or = 20 weeks. The fecundity rate is the number of pregnancies per 100 person-months. RESULT(S): Fecundity was 18.2% in infertile women with minimal or mild endometriosis and 23.7% in women without endometriosis (log-rank test). The fecundity rate was 2.52 per 100 person-months in women with endometriosis and 3.48 per 100 person-months in women with unexplained infertility. The crude and adjusted fecundity rate ratios were 0.72 and 0.83 (95% confidence interval = 0.53-1.32), respectively. CONCLUSION(S): The fecundity of infertile women with minimal or mild endometriosis is not significantly lower than that of women with unexplained infertility.