Master's Project Title:

Maternal Metabolic Status and Breastmilk Hormone Concentrations in Non-diabetic, Exclusively Breastfeeding Women

MCH Student:

Ghazeleh Sadr Dadres

Date of Defense:

June 26, 2017


Background/Objectives: Breastfeeding is a complex, bio­behavioral system that could link maternal obesity and increased risk of child obesity through transmission of hormones, and other potentially bioactive constituents in breastmilk. Our objective in this study was to test the association of pre-­pregnancy BMI, gestational weight gain (GWG), and sub-clinical glucose intolerance as predictors of leptin, insulin and adiponectin concentrations in breastmilk.

Methods: 135 exclusively breastfeeding, non­diabetic, non­smoking mothers (50% overweight or obese) were enrolled in the ongoing Mothers and Infants Linked for Healthy Growth (MILk) study. Mothers provided a single complete breastmilk expression between 8:00 and 10:00 am at 1- and 3 months post­partum using a hospital­-grade electric breast pump. Hormone concentrations were assayed in skimmed milk using commercially ­available immunoassay kits. Maternal pre­-pregnancy BMI, gestational weight gain (GWG) and oral glucose challenge (50g) test results (OGCT) were obtained from electronic health records. Maternal BMI and OGCT treated as continuous variables, and GWG as categorical variable were modeled using linear regression models adjusting for potential confounders.

Results: At 1- and 3 months, pre-­pregnancy BMI was positively associated with milk leptin and insulin levels (all p-values < 0.02) and negatively associated with milk adiponectin at 1-month (p-value = 0.048). GWG and milk leptin were positively associated (p-value < 0.01) but insulin and adiponectin revealed no association. A negative association between OGCT results and milk adiponectin at 3 months was also apparent (p-value = 0.054). OGCT results were not associated with insulin or leptin at 1- or 3 months.

Discussion: The present study advances the field of lactational programming by suggesting the not only weight status prior to pregnancy but also weight gain and subclinical hyperglycemia during pregnancy are associated with differences in the level of breastmilk hormones. Future work will assess these and other variations in breastmilk composition as they relate to infant growth, body composition, and metabolic health.