Breastfeeding and breast cancer risk

Breastfeeding for over a year is shown by studies to decrease the risk of invasive breast cancer by approximately 4.3%. (1)

All breastfeeding mothers have the risk of developing breast cancer lowered to 11%, while mothers nursing their babies for over a year experience a 26% reduction in breast carcinoma development. (2)

Reproductive risk factors for hormone-dependent tumours (ER+) align with previous findings showing significant protection against ER+ and ER− tumours with breastfeeding durations lasting up to 6 months and 12 months respectively. (3)

Reference

1. Dieterich CM, Felice JP, O’Sullivan E et al. Breastfeeding and health outcomes for the mother-infant dyad. Pediatr Clin North Am. 2013;60:31–48.
2. Chowdhury R, Sinha B, Sankar MJ et al. Breastfeeding and maternal health outcomes: a systematic review and meta-analysis. Acta Paediatr. 2015;104:96–113.
3. Romieu I, Biessy C, Carayol M et al. Reproductive factors and molecular subtypes of breast cancer among premenopausal women in Latin America: the PRECAMA study. Sci Rep. 2018;8:13109.