Obesity may impair lactogenesis II

Data from livestock species and experimental animal models suggest that exc ess body fatness may impair lactogenesis. For example, it has long been kno wn that overfed dairy cows are at risk of fat cow syndrome, a condition cha racterized by lactation failure in the early postpartum period. Obese rats often lose their litters in the early postpartum period to primary lactatio n failure. A negative association between high body mass index (BMI) before conception and the duration of lactation has been documented in studies fr om diverse human populations. Findings from our laboratory establish that a mong women who ever attempted to breastfeed their infants, high BMI before conception was also associated with failure to initiate breastfeeding succe ssfully. In a more recent study, we found that high prepregnant BMI was spe cifically associated with later onset of lactogenesis II. This was mediated by parity but not by breastfeeding behavior. Psychosocial factors related to a woman's intention to breastfeed and her planned duration of breastfeed ing did not modify this association. Taken together, these findings in anim als and women strongly suggest that maternal obesity in the perinatal perio d is a cause of delayed lactogenesis.