Study objective: To determine, in women with primary infertility, whether specific characteristics or behavioural factors are associated with the various pathological conditions identified as contributing to the infertility.
Design: Case-control study.
Setting: Seven institutions in the USA or Canada.
Participants: Study subjects were 1750 women who presented with primary infertility, among whom the main pathological cause of infertility was male factor (417), tubal obstruction (231), endometriosis (194), luteal phase defects (153), other ovulatory problems (193), cervical abnormalities (92), and polycystic ovarian disease (84) and 1765 control women who delivered their first child at the same institution.
Main results: Except for tubal obstruction and polycystic ovarian disease, the characteristics and behaviours of the women with infertility did not differ appreciably according to the pathological conditions recorded. Women with tubal obstruction had had more sexual partners, an earlier age at first intercourse, were more likely to have used an intrauterine device but less likely to have used a condom, and were more likely to have smoked cigarettes and to have used various recreational drugs than the other women. Women with polycystic ovarian disease were more obese, had had fewer sexual partners, and were less likely to have used cigarettes, contraceptives, and recreational drugs than the other women.
Conclusions: Sexually transmitted infections seem to increase the risk of tubal obstruction but not other causes of infertility. Obesity is associated with polycystic ovarian disease. These data offer few clues to the aetiology of infertility attributed to endometriosis, cervical abnormalities, luteal phase defects, other ovulatory defects, or to male factors.