The purpose of the present study was to examine the influence of maternal pre-pregnancy BMI and gestational weight gain (GWG) on initiation and duration of infant breast-feeding in a prospective birth cohort study.

Breast-feeding information was collected at 1, 3, 6 and 12 months postpartum. The association of pre-pregnancy BMI and GWG with delayed lactogenesis II and termination of exclusive breast-feeding was assessed with logistic regression analysis. The risk of early termination of any breast-feeding during the first year postpartum was assessed with Cox proportional hazards models.

Urban city in China.

Women with infants from the Ma’anshan Birth Cohort Study (n 3196).

The median duration of any breast-feeding in this cohort was 7·0 months. Pre-pregnancy obese women had higher risks of delayed lactogenesis II (risk ratio=1·89; 95 % CI 1·04, 3·43) and early termination of any breast-feeding (hazard ratio=1·38; 95 % CI 1·09, 1·75) adjusted for potential maternal and infant confounders, when compared with normal-weight women. No differences in breast-feeding initiation or duration of exclusive breast-feeding according to pre-pregnancy BMI were found. Moreover, GWG was not associated with any poor breast-feeding outcomes.

The present study indicated that pre-pregnancy obesity increases the risks of delayed lactogenesis II and early termination of any breast-feeding in Chinese women.