Timing of intrauterine insemination: an attempt to unravel the enigma

INTRODUCTION: Controlled ovarian stimulation (COS) with intrauterine insemination (IUI) is an effective treatment in cases of cervical factor, unexplained infertility and mild male factor. The optimal timing of IUI after human chorionic gonadotrophin (hCG) after COS with clomiphene citrate is debatable and may be a factor limiting success of same. This study was designed to scientifically determine if variation in the timing of IUI could affect the cycle outcome. MATERIALS AND METHODS: In a prospective randomized trial couples with mild male factor, unexplained infertility and mild endometriosis who underwent COS with IUI were recruited. COS was achieved with clomiphene citrate. Two hundred and four women underwent 461 cycles of IUI. Women were randomized to two groups: group I (104 patients, 231 cycles) had IUI 36 h after hCG, while group II (100 patients, 230 cycles) had IUI 24 h after hCG. Primary outcome included pregnancy rate per couple and per cycle. RESULTS: Fifty-four patients had pregnancy with and pregnancy rate per couple and per cycle were 32.6 and 14.7% in group I and 20 and 8.6% in group II, respectively (not statistically different). CONCLUSIONS: Altering timing of IUI after COS does not enhance pregnancy rates. IUI 36 h after hCG has marginally better pregnancy rates than 24 h. Timing of insemination may be kept at 24 or 36 h after hCG injection to suit the convenience of the clinic or care provider. The lack of statistical significance indicates need for larger studies to draw guidelines.