Polycystic ovary syndrome (PCOS) is a prevalent disorder that affects women of childbearing age and may be related to obesity and insulin resistance.

The purpose of this systematic review was to appraise the evidence of the impact of lifestyle modification (LSM) interventions on outcomes of women with PCOS.

Sources included Ovid Medline, OVID Embase, OVID Cochrane Library, Web of Science, Scopus, PsycINFO, and CINAHL (up to January 2011).

We included randomized controlled trials that enrolled woman of any age with PCOS who received LSM and compared them against women who received no intervention, minimal intervention, or metformin.

Two authors performed the data extraction independently.

We included 9 trials enrolling 583 women with a high loss to follow-up rate, lack of blinding, and short follow-up. Compared with minimal intervention, LSM significantly reduced fasting blood glucose (weighted mean difference, −2.3 mg/dL; 95% confidence interval, −4.5 to −0.1, I² = 72%, P = .04) and fasting blood insulin (weighted mean difference, −2.1 μU/mL, 95% confidence interval, −3.3 to −1.0, I² = 0%, P < .001). Changes in body mass index were associated with changes in fasting blood glucose (P < .001). Metformin was not significantly better than LSM in improving blood glucose or insulin levels. We found no significant effect of LSM on pregnancy rate, and the effect on hirsutism was unclear.

The available evidence suggests that LSM reduces fasting blood glucose and insulin levels in women with PCOS. Metformin has similar effects. Translation of these short-term effects to patient-important outcomes, beyond diabetes prevention, remains uncertain.