PRIMARY INFERTILITY AND ORAL-CONTRACEPTIVE STEROID USE

Objective: To determine the association between combined monophasic or al contraceptive (OC) use and primary infertility. Design: Case-contro l. Setting: Women serving as controls of the Cancer and Steroid Hormon e Study. Participants: Women were 19 to 40 years of age at first conce ption or infertility diagnosis. Based on 24 consecutive months of unpr otected intercourse without a recognized conception, 419 nulligravid w omen had primary infertility; controls were 2,120 fertile women. A cal endar of each woman's reproductive history was used to determine ferti lity status and contraceptive use before infertility diagnosis or firs t conception. Main Outcome Measure: Primary infertility. Results: Comb ined monophasic OC use was associated with a lower frequency of primar y infertility, particularly among younger (age 20 years) compared with older women (age 30 years) after adjusting for barrier method use and education. A similar association was found for duration of OC use. Wh en adjusted for age at first conception or infertility and barrier met hod, both higher (>50 mu g) and lower (less than or equal to 50 mu g) estrogen dose use were associated with decreased risk of primary infer tility. Conclusion: Combined monophasic OC use was associated with a l ower frequency of primary infertility.