Metformin use in patients undergoing in vitro fertilization treatment: results of a worldwide web-based survey

Purpose: To identify trends regarding therapeutic approaches to metformin administration in patients undergoing in vitro fertilization (IVF) treatment worldwide.

Methods: A retrospective evaluation utilizing the results of a web-based survey, IVFWorldwide (www.IVF-worldwide.com/), was performed. Results: Responses from 101 centers performing a total of 50,800 annual IVF cycles was performed. Of these cycles, 10.4 % (n = 5,260) reported metformin use during IVF cycles. Indications for metformin use in IVF cycles included polycystic ovary syndrome (PCOS) patients who were habitual abortions (67 %), had prior poor egg quality (61 %), had high serum insulin levels (56 %). Less reported was PCOS with obesity/anvoulation (29 %), PCOS with multiple manifestations (23 %) and glucose intolerance and insulin resistance (23 %). Over half of cycles (54 %) treated patients with metformin up to 3 months prior to starting IVF. A majority (82 %) of IVF cycles utilized 1500–2000 mg/day of metformin. A nearly equal percentage of centers continued metformin up to a positive β-HCG test (35 %) or to 12 weeks gestation (33 %). 70 % of IVF cycles reported increased pregnancy rates and decreased miscarriage rates due to the use of metformin. 75 % reported the data in the literature is not sufficient for reaching a definitive conclusion concerning metformin treatment in patients undergoing IVF. Conclusions: While metformin is used worldwide as an adjunct to standard IVF protocols, there is much variation in its use and the majority of centers report lack of evidence supporting its use.