The association of parity and breastfeeding with anti-Müllerian hormone levels at two time points

Abstract Objective To evaluate the association between parity and breastfeeding and anti-Mullerian hormone levels (AMH) and change in AMH levels over time. Furthermore, we examined whether AMH levels mediate the relation of parity and breastfeeding with age at menopause. Study design Observational, prospective cohort study. Main outcome measures AMH levels were assessed in a subset of premenopausal participants in the Nurses’ Health Study II, including 1619 women who provided a blood sample in 1996-1999 and an additional 800 women who provided a second premenopausal sample in 2010-2012. Results In multivariable linear regression models adjusted for parity, body mass index, smoking, and other factors, mean log AMH levels in 1996-1999 were 39% higher in women reporting ≥25 months of total breastfeeding vs. Conclusions Our results suggest that breastfeeding is associated with higher AMH levels and later onset of menopause, and support the hypothesis that observed relations of parity with AMH levels and menopause timing may be largely attributable to breastfeeding.