Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were included. Retrospective analyses, crossover trials, and studies in which the treatment groups were not homogeneous were excluded.
Specific interventions included in the review
FSH and hMG. Studies that used a combination of FSH and hMG, or used clomiphene citrate, were excluded.
Acceptable studies were grouped into three categories according to the type of protocol used: GnRH analog 'short (flare) protocol', where GnRH was started on the first day of the menstrual cycle and gonadotropins on the fourth day of the cycle; GnRH analog 'long protocol', where GnRH was started either in the follicular phase of the menstrual cycle or late luteal phase of the previous cycle; and the 'no GnRH analog protocol' in which pituitary desensitisation protocols were not used.
Participants included in the review
Infertile women undergoing IVF treatment.
Outcomes assessed in the review
The primary outcome for the analysis was the clinical pregnancy rate per cycle of treatment. Studies where the pregnancy rate per cycle were not mentioned were excluded from the review.
Other outcome measures, such as the rate of multiple pregnancies and of ovarian hyperstimulation syndrome, were not analysed because few studies provided this information.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for the review, or how many of the reviewers performed the selection.