Effect of metformin and exenatide on pregnancy rate and pregnancy outcomes in overweight or obese infertility PCOS women: long-term follow-up of an RCT.

Purpose: The majority of Polycystic ovary syndrome (PCOS) are overweight or obese with increased infertility and high risk of pregnancy complications. We aim to compare efficacy of metformin and exenatide on spontaneous pregnancy rate, overall pregnancy rate after assisted reproductive technology treatment (ART) and pregnancy outcomes in overweight or obese infertility PCOS.

Methods: In this long-term follow-up study, 160 overweight or obese infertility Chinese PCOS were randomized to exenatide or metformin treatment for 12 weeks. Afterward, all were treated with metformin alone until pregnancy confirmed and followed until delivery. If patients failed spontaneous pregnancy during the second 12 weeks, ART could be offered until end of 64 weeks. The primary outcome was spontaneous pregnancy rate.

Results: At week 24, 29.2% of women in exenatide group conceived spontaneously while 14.7% in metformin group (p = 0.03). At week 64, total pregnancy rates were 79.2% in exenatide group and 76% in metformin group without significant difference (p = 0.65). Between two groups, there was no significant difference of pregnancy outcomes (p > 0.05). A stepwise logistic regression showed that spontaneous pregnancy was positively associated with body weight reduction and HOMA-IR improvement in either group.

Conclusion: In overweight or obese infertility Chinese PCOS, 12 weeks pregestational exenatide treatment resulted in more spontaneous pregnancy likely due to greater weight reduction and improvement of insulin resistance compared with metformin treatment without obvious benefit on overall pregnancy rate after ART or pregnancy outcomes of successful conceived women.

Trial Registration: This clinical trial was registered at Chinese Clinical Trials Registry (ChiCTR-IIR-16008084) on 13/3/2016.