Synchronised approach for intrauterine insemination in subfertile couples

Intrauterine insemination (IUI) should logically be performed around the moment of ovulation. Since spermatozoa and oocytes have only limited survival times correct timing is essential. As it is not known which technique of timing for IUI results in the best treatment outcome, we compared different techniques for timing IUI and different time intervals.

To evaluate the effectiveness of different synchronisation methods in natural and stimulated cycles for IUI in subfertile couples.

We searched for all publications which described randomised controlled trials of the timing of IUI. We searched the Cochrane Menstrual Disorders and Subfertility Group Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), (1966 to March 2009), EMBASE (1974 to March 2009) and Science Direct (1966 to March 2009) electronic databases. Furthermore, we checked the reference lists of all obtained studies and performed a handsearch of conference abstracts.

Only truly randomised controlled trials comparing different timing methods for IUI were included. The following interventions were evaluated: detection of luteinising hormone (LH) in urine or blood, single test; human chorionic gonadotropin (hCG) administration; combination of LH detection and hCG administration; basal body temperature chart; ultrasound detection of ovulation; gonadotropin-releasing hormone (GnRH) agonist administration; or other timing methods.

Two review authors independently selected the trials to be included according to the above mentioned criteria. We performed statistical analyses in accordance with the guidelines for statistical analysis developed by The Cochrane Collaboration.

Ten studies were included comparing urinary LH surge versus hCG injection; recombinant hCG versus urinary hCG; and hCG versus a GnRH agonist. One study compared the optimum time interval from hCG injection to IUI. The results of these studies showed no significant differences between different timing methods for IUI expressed as live birth rates: hCG versus LH surge (odds ratio (OR) 1.0, 95% CI 0.06 to 18); urinary hCG versus recombinant hCG (OR 1.2, 95% CI 0.68 to 2.0); and hCG versus GnRH agonist (OR 1.1, 95% CI 0.42 to 3.1). All the secondary outcomes analysed showed no significant differences between treatment groups.

There is no evidence to advise one particular treatment option over another. The choice should be based on hospital facilities, convenience for the patient, medical staff, costs and drop-out levels. Since different time intervals between hCG and IUI did not result in different pregnancy rates, a more flexible approach might be allowed.