Breastfeeding

Suggested

3 studies · 1 recommendation

Last updated: February 25, 2026

Suggested3 studies

Breastfeeding linked to over 50% reduction in ovarian cancer risk

Three studies involving approximately 351 participants support breastfeeding as a protective factor against ovarian cancer. Two case-control studies from Indonesia found consistent risk reductions: one reported a 55% decrease in ovarian cancer risk with lifetime breastfeeding (OR=0.45, 95% CI 0.23–0.91), with a dose-response relationship showing greater protection beyond 24 months of cumulative breastfeeding. The second found non-breastfeeding women had 2.7 times higher odds of ovarian cancer (OR=2.684, 95% CI 1.326–5.432, p=0.009). A Latin American and Caribbean consensus statement included ovarian cancer protection in its formal recommendations, citing suppressed ovulation and reduced hormonal stimulation during lactation as the likely biological mechanism. Longer cumulative breastfeeding duration consistently corresponded to greater risk reduction across studies.

Evidence

Risk Factors Associated with the Incidence of Ovarian Cancer

Authors: Martanti, Listyaning Eko, Rochsas, Auliana, Runjati, Runjati

Published: February 28, 2024

A case-control study at RSUD Dr. H. Abdul Moeloek, Lampung Province, compared 70 ovarian cancer cases with 70 controls selected by simple random sampling. Women without a history of breastfeeding had significantly higher odds of ovarian cancer (p-value = 0.009, OR = 2.684, 95% CI = 1.326–5.432). The association remained statistically significant, indicating that breastfeeding is a modifiable protective factor against ovarian cancer in this population.

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Latin American and the Caribbean Code Against Cancer 1st edition : Weight, physical activity, diet, breastfeeding, and cancer

Authors: Aburto, T.C., Barnoya, J., Barquera, S., Canelo-Aybar, C., Cavalcante, T.M., Corvalán, C., Espina, C., Feliu, A., Hallal, P.C., Reynales-Shigematsu, L.M., Rivera, J.A., Romieu, I., Santero, Marilina, Stern, M.C., Universitat Autònoma de Barcelona

Published: January 1, 2023

The consensus statement notes breastfeeding could protect against ovarian cancer, representing a secondary protective benefit alongside the more established breast cancer protection. While the evidence for ovarian cancer protection is described as less definitive than for breast cancer, it was considered sufficient for inclusion in the Latin American and Caribbean Code Against Cancer recommendations. The biological mechanism likely involves suppression of ovulation and reduced hormonal stimulation during lactation periods.

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Hubungan Antara Menyusui Dengan Risiko Kanker Ovarium

Authors: ADISASMITA, A. (ASRI), DWIPOYONO, B. (BAMBANG), MARYANI, D. (DINI)

Published: September 1, 2016

A case-control study at Dharmais Cancer Hospital in Indonesia enrolled 71 ovarian cancer patients as cases and 140 cervical cancer patients as controls. Lifetime breastfeeding was associated with a 55% decrease in ovarian cancer risk (OR=0.45, 95% CI 0.23–0.91) among all cases. Among parous women specifically, the risk reduction was 53% (OR=0.47, 95% CI 0.23–0.96). Results were adjusted for education level and menopause status at diagnosis. A dose-response relationship was observed: longer cumulative breastfeeding duration corresponded to lower ovarian cancer risk, with reductions exceeding 50% for women with lifetime breastfeeding of 24 months or more.

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