Multiple pregnancy rate in patients undergoing treatment with clomifene citrate for WHO group II ovulatory disorders: a systematic review.

Clomifene citrate has long been associated with a multiple pregnancy rate of up to 8-10%. Studies from which these figures originated have largely included patients who received clomifene outside of current national and international treatment guidelines. In January 2020, a systematic review of MEDLINE and relevant reference lists was conducted. Studies were included that reported multiple pregnancy rate in a cohort of patients undergoing treatment with single agent clomifene citrate for WHO group II dysovulatory subfertility. Twelve studies were included in the analysis, with a total sample size of 1,387 patients. The overall multiple pregnancy rate was 3.8% (3.6% twins/0.2% triplets); this dropped to 2.4% (all twins) when studies with a mean BMI ≥35kg/m2 were excluded. This review suggests that contemporary single agent clomifene use following current guidelines in terms of indication, results in a lower than expected multiple pregnancy rate. Further evidence from clinical practice is required to ensure that patients are adequately informed.