INTRAUTERINE INSEMINATION - EFFECT OF THE TEMPORAL RELATIONSHIP BETWEEN THE LUTEINIZING-HORMONE SURGE, HUMAN CHORIONIC-GONADOTROPIN ADMINISTRATION AND INSEMINATION ON PREGNANCY RATES

The optimal time period for intrauterine insemination (IUI) in relatio n to either luteinizing hormone (LI-I) surge or human chorionic gonado trophin (HCG) administration leading to the best pregnancy rates has n ot been determined, In this study, 856 consecutive human menopausal go nadotrophin (HMG)-stimulated and 49 natural unstimulated IUI cycles ca rried out at a reproductive medicine unit affiliated with a tertiary c entre were analysed in a retrospective fashion. There were three scena rios in the temporal relationship of the LPI surge, HCG administration and artificial insemination. These were (group A) subjects who had an endogenous LH surge but were not given BCG; (group B) subjects who we re given HCG after as observed LB surge, and (group C) subjects who we re given HCG before the LH surge. The overall pregnancy rate (PR) was 16% per cycle. The PR was 9% in group A, 20% in group B and 14% in gro up C, The PR in group B: was significantly better than group C (P = 0. 04). In group B, the longer the time interval between the LH surge and HCG administration, the better the PR up to 20 h (P = 0.025): the tim ing of IUI based on the LI-I surge was not critical to the achievement of pregnancy within 3 days. fn group C, PR improved with the increasi ng interval between HCG and IUI from <28 h up to 60 h. We conclude tha t a better PR is achieved if a spontaneous LH surge occurs before HCG administration, especially where the administration of BCG is delayed 8-20 h after an observed LH surge; the timing of IUI based on the LH s urge is not critical to the achievement of pregnancy within 3 days.