Predictive factors for pregnancy after intrauterine insemination (IUI): an analysis of 1038 cycles and a review of the literature

Objective: To determine the predictive factors for pregnancy after IUI.

Design: Retrospective study.

Setting: A single university medical center.

Patient(s): One thousand thirty-eight IUI cycles in 353 couples were studied between 2002 and 2005.

Intervention(s): Ovarian stimulation via SC injection of FSH or hMG was performed daily; IUI was then performed 36 hours after triggering ovulation if at least one follicle measuring >16 mm and an endometrial thickness of >7 mm (with triple-line development) were obtained.

Main outcome measure(s): Clinical pregnancy rates were analyzed according to the woman's age, the type of infertility, the spermogram characteristics, the total motile spermatozoa (TMS) count, the E(2) level before hCG injection, and the number of mature follicles.

Result(s): The couple with the best chance of pregnancy can be described as follows: an under 30 woman with cervical or anovulatory infertility and a man with a TMS >or=5 million spermatozoa. The "ideal" stimulation cycle enables the recruitment of two follicles measuring >16 mm with an E(2) concentration >500 pg/mL on the day of hCG administration. The best results are obtained when IUI is performed using a soft catheter.

Conclusion(s): This study enabled the characterization of many prognostic factors for pregnancy and particularly those for women at risk of multiple pregnancies after IUI.