The safety and effectiveness of stepwise and low-dose administration of follicle stimulating hormone in WHO group II anovulatory infertile women: evidence from a large multicenter study in Spain.

Purpose: Our goal was to investigate the safety, effectiveness, and feasibility for the practicing physician of stepwise and low-dose administration of FSH in WHO group II anovulatory infertile women.
Methods: Infertile female patients (n = 234) suffering from WHO group II anovulation, and who failed to became pregnant with clomiphene citrate, were included in a multicenter, prospective, clinical study of treatment with a protocol of chronic low-dose and small incremental rises with urinary purified or highly purified FSH. Follicular development was monitored with ultrasonographic scans.
Results: The 234 patients received a total of 534 cycles of treatment, for a mean number of 2.3 treated cycles per patient. hCG was withheld in 65 (12.2%) cyles because of no response and in 28 (5.2%) cycles because of hyperresponse. Of the remaining 441 cycles, 419 (95%) were ovulatory, and in 198 (47.3%) of these cycles a single dominant follicle developed. There were 93 pregnancies (39.7% per patient), for a cycle fecundity rate of 17.4%. Cumulative conception rate after two treated cycles was 33.5%. There were 14 (15%) pairs of twins and 10 (10.8%) spontaneous miscarriages. The prevalence of complications was low with no cases of severe OHSS. Basal LH/FSH ratio was significantly higher in the pregnant group of patients than in nonpregnant women.
Conclusions: Stepwise and chronic low-dose administration of FSH is a safe and effective method for treatment of WHO group II anovulatory infertility, mainly in those patients having high LH/FSH ratios.