The clinical efficacy of low-dose step-up follicle stimulating hormone administration for treatment of unexplained infertility

The present study was designed to compare the clinical efficacy of low-dose step-up follicle stimulating hormone (FSH) administration with conventiona l FSH protocol (FSH was injected daily starting with a dose of 150 IU), bot h combined with intrauterine insemination (IUI), for the treatment of unexp lained infertility. A total of 97 unexplained infertility couples was rando mly assigned to one or other of the two treatment groups, either convention al FSH with IUI (48 patients) or low-dose step-up FSH with IUI (49 patients ), and only the first treatment cycle was evaluated in each protocol. The d ifference in pregnancy rates per cycle was not statistically significant be tween the low-dose FSH group and the conventional group [seven of 49 (14.3% ) and seven of 48 (14.6%) respectively]. A significant reduction in the inc idence of ovarian hyperstimulation syndrome (OHSS) was observed in the low- dose group (8.3% versus 27.1%, P < 0.05). The incidence of moderate OHSS re quiring hospitalization was reduced significantly in the low-dose group (lo w-dose 0% versus conventional 16.7%, P < 0.01). However, the low-dose proto col did not completely prevent multiple pregnancies. Our results suggest th at the low-dose step-up FSH treatment appeared to be useful for the treatme nt of unexplained infertility because of the high pregnancy rates and the s ignificant decrease in the incidence of OHSS.