Controlled ovarian hyperstimulation and intrauterine insemination for treatment of unexplained infertility should be limited to a maximum of three trials.

Objective: To investigate the optimum number of cycles of controlled ovarian hyperstimulation and intrauterine insemination in the treatment of unexplained infertility.

Design: Observational prospective study.

Setting: In vitro fertilization embryo transfer center.

Patient(s): Five hundred ninety-four couples with unexplained infertility.

Intervention(s): Controlled ovarian hyperstimulation (COH), intrauterine insemination (IUI), in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI).

Main Outcome Measure(s): Cycle fecundity.

Result(s): One to 3 cycles of COH/IUI were performed in 594 patients (group A) undergoing 1,112 cycles (mean, 1.9 cycles/patient). Up to 3 further trials (cycles 4-6) of COH/IUI were then performed in 91 of these women (group B), a total of 161 cycles (mean, 1.8 cycles/patient). A historical comparison group C consisted of 131 patients with 3 failed cycles of COH/IUI who underwent 1 cycle of IVF and ICSI at our center. In group A, 182 pregnancies occurred, with a cycle fecundity of 16.4% and a cumulative pregnancy rate (PR) of 39.2% after the first 3 cycles. In group B, 9 pregnancies occurred in cycles 4-6, with a cycle fecundity of 5.6%, significantly lower than that of group A (P<.001). The cumulative PR rose to 48.5% by cycle 6, a further increase of only 9.3%. In the women undergoing IVF and ICSI in group C, 48 pregnancies occurred, with a cycle fecundity of 36.6% per cycle, significantly higher than that of group B (P<.001).

Conclusion(s): In unexplained infertility, the cycle fecundity in the first three trials of COH and IUI was higher than in cycles 4-6, with a statistically significant difference. Patients should be offered IVF or ICSI if they fail to conceive after three trials of COH and IUI.