Follicular response and pregnancy among infertile women undergoing ovulation induction and intrauterine insemination

Abstract

Objective To determine the relationship between ovarian follicular response (number and diameter of follicles) to ovulation induction agents and pregnancy. Design Retrospective cohort study. Setting Hospital-based center of reproductive medicine. Patient(s) Three hundred twenty-two clinically diagnosed infertile couples undergoing 1,483 cycles of ovulation induction and IUI. Intervention(s) Oral and injectable fertility drugs were administered for 2–10 cycles; ultrasound follicular measurements were recorded around time of ovulation; hCG was administered when follicles were 18–20 mm or more in diameter; IUI was performed 36–40 hours after administration of hCG. Main outcome measure(s) A first positive pregnancy test as indicative for conception. Result(s) Women with follicular diameters ≥20 mm were less likely to become pregnant as compared to women with diameters between 15.00 and 19.99 mm (risk ratio [RR] = 0.58, 95% confidence interval [CI] = 0.35, 0.97). Women ≥30 years of age were half as likely to become pregnant as compared to women <30 years (RR = 0.51, 95% CI = 0.30, 0.85). Likelihood of pregnancy increased by 21% for each prior pregnancy (RR = 1.21, 95% CI = 1.00, 1.47). Conclusion(s) Maternal age, gravidity, and follicular diameters around the time of insemination are prognostic factors in the likelihood of pregnancy.