After breast cancer chemotherapy, ovarian function returned in under half of premenopausal women by five years

Design

Systematic review and random-effects meta-analysis

Population

34 studies, 10,216 premenopausal women with breast cancer

Primary outcome

Ovarian function recovery after chemotherapy

Effect

30.4% at 12 months; 43.4% at 60 months; older age OR 0.25

A systematic review and meta-analysis in Breast Cancer Research and Treatment (22 September 2026) pooled 34 studies of 10,216 premenopausal women with breast cancer treated with chemotherapy.

Ovarian function had recovered in 30.4% at 12 months, 38.5% at 24 months and 43.4% at 60 months, with a mean time to recovery of 12.3 months. Older age (OR 0.25) and longer chemotherapy (OR 0.68) were associated with lower recovery. Higher pretreatment anti-Müllerian hormone appeared protective in individual studies but not in pooled estimates.

The intervals at 24 and 60 months are very wide because fewer studies reported late outcomes and definitions of recovery varied. The message for counselling is still clear.

• Discuss fertility and ovarian function before starting chemotherapy in every premenopausal woman with breast cancer
• Refer for fertility preservation counselling before treatment, not after
• Tell older premenopausal women that recovery is less likely
• Do not assume amenorrhoea after chemotherapy means permanent menopause — recovery can take a year or more
• Consider contraception needs, since ovarian function may return

Why it matters

It gives women a realistic figure for a long-term consequence that often goes undiscussed until it is too late to act.

Don't overread it

Estimates beyond 12 months are imprecise, and definitions of ovarian recovery differed between studies.

The statistics, in plain English

The 60-month estimate of 43.4% has a confidence interval from 9.4% to 84.9% — so wide that the true figure is very uncertain. The 12-month estimate (30.4%, 17.5% to 47.3%) is more reliable.

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