Lifestyle treatment in PMOS: more regular cycles and modest metabolic gains, across 34 studies

Design

Systematic review and random-effects meta-analysis

Population

34 studies, 1,871 women with PMOS

Primary outcome

Reproductive, anthropometric and metabolic outcomes vs minimal or no treatment

Effect

Regular cycles OR 4.03 (95% CI 1.16 to 14.05); fasting insulin MD −6.08 (−9.86 to −2.30)

A systematic review and meta-analysis in PLoS Medicine (23 September 2026) pooled 34 studies with 1,871 women with polyendocrine metabolic ovarian syndrome (PMOS, the new name for polycystic ovary syndrome), comparing diet, exercise or combined lifestyle programmes with minimal or no treatment.

Women in lifestyle programmes were more likely to achieve regular menstrual cycles (OR 4.03, 95% CI 1.16 to 14.05; five studies, 237 women) and had small reductions in waist circumference (mean difference −2.38), fasting glucose (−0.13) and fasting insulin (−6.08). Diet had the larger effect on fasting glucose; exercise on waist and fasting insulin. The gains were broader in women who were overweight or obese, including falls in weight, testosterone and LDL cholesterol.

The limitation is heterogeneity, which was high on almost every outcome (I² 71-90%). The pooled numbers are an average across quite different programmes, and the menstrual regularity estimate rests on only five small studies.

In practice this supports what the international guideline already says: lifestyle first, tailored to the woman, with no single diet or exercise format shown to be superior. Pick what she will sustain.

• Offer structured lifestyle support as first-line treatment in PMOS, alongside rather than instead of drug treatment where needed
• Choose diet or exercise by preference — neither was clearly superior overall
• Expect a larger metabolic benefit in women who are overweight or obese
• Track cycle regularity, waist and fasting glucose as the outcomes most likely to move
• Screen for dysglycaemia in PMOS regardless of whether a lifestyle programme is under way

Why it matters

It gives numbers to a recommendation that has mostly rested on consensus, and shows that the format matters less than doing something.

Don't overread it

Heterogeneity was high throughout, and the cycle-regularity result rests on five small studies.

The statistics, in plain English

An odds ratio of 4.03 means women in lifestyle programmes had about four times the odds of regular cycles, but the confidence interval runs from 1.16 to 14.05 — the true effect could be small or very large. I² of 71-90% means most of the variation between studies reflects real differences in the programmes and populations, not chance, so the pooled average describes no single programme well.

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