Predicting and optimizing success in an intra-uterine insemination programme

We analysed 381 consecutive cycles of homologous intrauterine insemination (IUI) in 215 infertile couples, resulting in 48 pregnancies (12.6%/cycle, 22.3%/patient). Cycle fecundity ranged from 0.11 to 0.14 in women aged 25-39 years, falling to 0.04 beyond age 40 years. Of the 48 pregnancies, 43 occurred in the first three treatment cycles, in which fecundity was 0.14, 0.16 and 0.10 respectively. Beyond three cycles, fecundity was 0.07 (P = 0.05 versus first two cycles). The occurrence of pregnancy varied with diagnosis (P = 0.04). Fecundity was significantly greater for women with ovulatory dysfunction (0.30) than for endometriosis, male factor, tubal factor, idiopathic infertility or multifactorial (0.08-0.14). Ovulation induction using menopausal gonadotrophins offered significant advantage over natural cycles or cycles using clomiphene citrate without gonadotrophins (0.15 versus 0.03, P = 0.01). Cycles in which pre-ovulatory surges were either induced or supported with human chorionic gonadotrophin (HCG) were superior to spontaneous luteinizing hormone surges (0.13 versus 0.03, P = 0.05). Recruitment of at least two mature (> 1.6 cm) follicles was critical. Only one pregnancy occurred in 64 cycles characterized by one mature follicle, compared with a pregnancy rate of 0.15 in cycles characterized by two or more mature follicles (P = 0.006). IUI is not beneficial to women > 40 years old, and has the best chance of success within three cycles. Multiple follicle recruitment using gonadotrophin-based stimulation protocols and mid-cycle HCG are necessary to achieve an acceptable pregnancy rate.