Why can’t Rita get pregnant?

Rita, a 34-year-old nulligravida, presents with her husband, Stewart, for investigation of a 13-month history of primary infertility.

She stopped the oral contraceptive pill when they decided to start trying to conceive, and her menstrual cycles were 40-45 days long. Neither she nor Stewart have any contributing medical history.

Rita's cycles had been regular prior to starting the pill when she was in her 20s. Menarche occurred when she was 11 years old. Neither Rita's nor Stewart's family history revealed any problem that may contribute to sub-fertility.

She exercised three times a week, for an hour at a time. She did not participate in marathons or triathlons. She did not have an eating disorder on discrete questioning.

Rita appeared fit and well, with a BMI of 23. She had no signs of hirsutism or acne. Breast examination was normal, and she