Background: Time to onset of stage II lactogenesis varies widely, and delayed onset of lactogenesis (OL) is common among first-time mothers in the United States. Higher body mass index, older age, and larger infant birth weight are identified risk factors for delayed OL; all are known correlates with glucose metabolism. Our objective was to prenatally assess maternal biomarkers related to metabolic health and determine the extent to which these biomarkers predict timing of OL.
Methods: We enrolled a population-based sample of expectant primiparas attending a single prenatal clinic. We obtained a blood sample 1-hour post-glucose load from an antenatal oral glucose challenge test and assayed for the following biomarkers: serum insulin, glucose, adiponectin, leptin, C-reactive protein, interleukin-6, resistin, and tumor necrosis factor-α. Our outcome measure was timing of OL, based on maternal report at 3-5 days postpartum. We used linear regression to model OL hour.
Results: Twenty-six of 29 (90%) agreed to screening, 18 delivered at term and initiated breastfeeding, and 16 have complete data. Median (minimum-maximum) postpartum body mass index was 27.4 (21.8-34.7) kg/m(2), and median time to OL was 64 (10-121) hours. The model, OL = 232 - 34.9(ln[ratio insulin/glucose]) - 1.4(adiponectin), explained 56% of the variation in OL hour (p = 0.005) and was not weakened by potential confounders.
Conclusions: Higher serum insulin secretion relative to serum glucose after a glucose challenge and higher serum adiponectin are associated with earlier onset of OL. These findings suggest that factors associated with better glucose tolerance predict earlier OL.
Trial registration: ClinicalTrials.gov NCT01233427.