Objectives Identify disparities in breastfeeding initiation and continuation among sexual minority women (SMW) and determine if known risk factors explain any observed disparities.

Methods We used data from the 2006 to 2017 National Survey of Family Growth female pregnancy questionnaire. We measured sexual orientation using self-reported sexual identity and histories of same-sex sexual experiences reported by women (heterosexual-WSM [women who only reported sex with men]; heterosexual-WSW [women who reported sex with women]; bisexual, and lesbian. In total, we had 18,696 births that occurred within the last 10 years and used logistic and multinomial regression models to assess sexual orientation disparities in breastfeeding initiation and duration that clustered on women to account for potential multiple births to a woman.

Results Compared to heterosexual-WSM, infants born to lesbian-identified women had decreased odds of ever being breastfed (OR 0.55, 95% CI 0.30, 0.99) and a decreased relative risk of being breastfed more than 6 months (RRR 0.46, 95% CI 0.22, 0.97). Infants of heterosexual-WSW had an increased odds of ever breastfeeding (OR 1.40, 95% CI 1.12, 1.74) and increased relative risk of breastfeeding more than 6 months (RRR 1.32, 95% CI 1.02, 1.69).

Conclusions Our results show that infants born to lesbian-identified women were less likely to be breastfed than those born to their heterosexual counterparts, even after adjusting for several factors associated with breastfeeding behaviors. We found no differences in breastfeeding between bisexual women and heterosexual-WSM. Understanding and addressing the barriers sexual minority women face for breastfeeding is critical for ensuring maternal and child health equity.