Intrauterine insemination before transfer of frozen-thawed embryos may improve the pregnancy rate for couples with unexplained infertility: preliminary results of a randomized prospective study

Objective: To evaluate whether a combination of IUI and frozen-thawed embryo transfer (FT-ET) with ovulation induction would improve the PR in couples with unexplained infertility. Design: Prospective. randomized study. Setting: In Vitro Fertilization Unit, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel. Patient(s): Sixty-two patients with unexplained infertility were assigned into two groups. The study group was composed of 32 women (38 cycles) who received ovulation induction followed by IUI and FT-ET. The control group was composed of 30 women (33 cycles) who received ovulation induction followed by FT-ET. Intervention(s): Clomiphene citrate (CC) and hCG, IUI, and FT-ET. Main Outcome Measure(s): Pregnancy rate (PR) per cycle, PR per ET. Result(s): In the study group, the PR per cycle and per ET were 36.8% (14 of 38) and 40.6% (13 of 32), respectively. In the control group, the PR per cycle and per ET were 12.1% (4 of 33) and 14.3% (4 of 28), respectively. Statistically significant differences were found between the two groups in the PR per cycle (P = .02) and PR per ET (P = .03). No statistically significant difference was found between the groups for the stage in which the embryos were cryopreserved, the survival cleavage rates after thawing, grading of thawed embryos, and number of embryos transferred. Conclusion(s): In couples with unexplained infertility, the PR may be improved by combining IUI and FT-ET with ovulation induction. Performing IUI before thawing may prevent treatment cancellation in cycles with no surviving embryos. (C) 2000 by American Society for Reproductive Medicine.