Limitations of this Cochrane review included the small number of relevant studies comparing different types of gonadotropins, low power, heterogeneous risk of bias in individual trials, and low to nonexistent rates of more rare conditions (eg, ectopic pregnancy, ovarian hyperstimulation syndrome). Most studies included patients with PCOS who had not conceived or failed to respond to clomiphene. The study comparing gonadotropins with continued clomiphene therapy, however, specifically included patients who had previously ovulated while taking clomiphene but were unable to conceive, highlighting differences in patient selection across trials. Included studies were conducted in socioeconomically advantaged countries, limiting generalizability.
Several trials lacked complete data, particularly those comparing human menopausal gonadotropin with purified and highly purified urinary FSH.
, , , , , These studies were generally published between 1985 and 1991, a period when ovulation and clinical pregnancy rates were still accepted as primary end points according to the guidelines at the time, which may explain the missing data.
Another notable limitation was the absence of data on gonadotropin dose and treatment duration per patient. Furthermore, four of the studies evaluating gonadotropins also incorporated patients receiving intrauterine insemination, which may have artificially increased pregnancy rates.
, , However, intrauterine insemination was consistently used in both study arms, so its influence on comparative outcomes was likely minimal. In the study that compared gonadotropins with continued clomiphene citrate, participants were randomized to either intrauterine insemination or intercourse in an effort to control for this potential confounding factor. The most recent American College of Obstetricians and Gynecologists practice guideline for PCOS recommends clomiphene as the first-line agent for ovulation induction, with gonadotropins as a second-line consideration.
The original manuscript was published in
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