JAMA

Common supplement fails to prevent pregnancy complications in PCOS

September 10, 2025

Myo-inositol supplementation during pregnancy doesn't reduce the risk of major pregnancy complications in individuals with PCOS, according to a large randomized trial.

Study details: The MYPP trial was a multicenter, double-blind, placebo-controlled trial enrolling 464 pregnant individuals with PCOS between 2019 and 2023 across 13 hospitals in the Netherlands. Participants were randomized to receive either myo-inositol 4 g daily plus 0.4 mg folic acid or placebo (0.4 mg folic acid) from randomization until delivery. Primary outcome was a composite of gestational diabetes, preeclampsia, and/or preterm birth.

Results: No significant difference was observed in the incidence of the composite primary outcome between the myo-inositol and placebo groups (25.9% vs. 25.4%). Subgroup analyses by biochemical hyperandrogenism and BMI showed no treatment effect modification. Adherence rates were moderate and similar between groups.

Source:

van der Wel AWT, et al. (2025, September 8). JAMA. Myo-inositol Supplementation to Prevent Pregnancy Complications in Polycystic Ovary Syndrome: A Randomized Clinical Trial. https://pubmed.ncbi.nlm.nih.gov/40920401/