Endometriosis is a painful condition in women in which the endometrium grows outside the uterus. The association between breastfeeding and the incidence of endometriosis has not been studied. This study aims to examine the association of lifetime breastfeeding, exclusive breastfeeding, and postpartum amenorrhea with the risk of endometriosis in parous women.

This prospective cohort study included a total of 72,394 women who reported one or more pregnancies lasting at least six months, of whom 3,296 had laparoscopically confirmed endometriosis. The total duration of breastfeeding, exclusive breastfeeding, and postpartum amenorrhea was reported. The primary outcome of the study was confirmed endometriosis in parous women.

The findings suggested a significant association between exclusive breastfeeding and a reduced risk of endometriosis. Among women with a total lifetime length of breastfeeding of less than a month, the incidence of endometriosis was 453 cases per 100,000 person-years, as compared with 184 cases per 100,000 years in women with a total lifetime length of breastfeeding of ≥36 months. Every additional three months of total breastfeeding per pregnancy were associated with an 8% lower risk of endometriosis.

The research concluded that breastfeeding was significantly associated with a reduced risk of endometriosis in parous women.

Ref: https://www.bmj.com/content/358/bmj.j3778