Does the addition of recombinant LH in WHO group II anovulatory women over-responding to FSH treatment reduce the number of developing follicles? A dose-finding study

BACKGROUND: In anovulatory women undergoing ovulation induction, addition of recombinant human LH (rLH) to FSH treatment may promote the dominance of a leading follicle when administered in the late follicular phase. The objective of this study was to find the optimal dose of rLH that can maintain the growth of a dominant follicle, whilst causing atresia of secondary follicles. METHODS: Women with infertility due to anovulation and over-responding to FSH treatment were randomized to receive, in addition to 37.5 IU recombinant human FSH (rFSH), either placebo or different doses of rLH (6.8, 13.6, 30 or 60 mug) daily for a maximum of 7 days. The primary efficacy endpoint was the proportion of patients who had exactly one follicle greater than or equal to16 mm on hCG day. RESULTS: Among 153 enrolled patients, the five treatment groups were similar in terms of baseline characteristics. The proportion of patients with exactly one follicle greater than or equal to16 mm ranged from 13.3% in the placebo group to 32.1% in the 30 mug rLH group (P=0.048). The pregnancy rate ranged from 10.3% in the 60 mug group to 28.6% in the 30 mug rLH group. Adverse events were similar between groups. CONCLUSIONS: In patients over-responding to FSH during ovulation induction, doses of up to 30 mug rLH/day appear to increase the proportion of patients developing a single dominant follicle (greater than or equal to16 mm). Our data support the 'LH ceiling' concept whereby addition of rLH is able to control development of the follicular cohort.