Abstract
Adequate milk production is key for optimal infant growth, yet women often wean due to perceived low milk production (LMP). Maternal adiposity and gestational diabetes mellitus (GDM) are known potential risk factors for LMP and may alter both hormonal and macronutrient composition of human milk. This study aims to investigate the hormonal and macronutrient composition of human milk in relation to LMP, particularly in the context of maternal adiposity and GDM. Human milk samples were collected from 68 women with LMP and 160 women with normal milk production during 1–6 months postpartum. Of the 228 participants with the mean pre-pregnancy BMI of 26.3 ± 6.0 kg/m2, 80 (35.1%) had GDM. Concentrations of hormones (estrone, estradiol, progesterone, insulin, leptin, adiponectin) and macronutrients (fat, protein, lactose, glucose) were measured and compared between the two groups. Univariable and multivariable logistic regression analyses were conducted, adjusting for potential confounders such as maternal body mass index (BMI) and GDM, to assess the relationships between hormone and macronutrient concentrations, and milk production. Preliminary analyses indicated that higher concentrations of estrone (p < 0.001), leptin (p = 0.009), insulin (p = 0.002), protein (p = 0.012), and lactose (p = 0.004) were associated with LMP. After adjusting for maternal BMI and GDM in the univariable models, all of these associations remained, and progesterone (p = 0.045) also emerged as positively associated with LMP. In multivariable regression, followed by stepwise model selection, estrone (p < 0.001), protein (p < 0.001) and lactose (p = 0.015) demonstrated the strongest associations with LMP, with maternal BMI also contributing significantly (p = 0.010). The findings suggest that hormone and macronutrient concentrations in human milk may reflect LMP status and provide insights into the underlying biological mechanisms associated with LMP.
Author Contributions
Conceptualization, X.J., C.T.L. and D.T.G.; methodology, C.T.L. and Z.G.; software, X.J. and C.T.L.; validation, X.J. and Z.G.; formal analysis, X.J.; investigation, X.J.; resources, D.T.G.; data curation, X.J., J.L.M. and Z.G.; writing—original draft preparation, X.J.; writing—review and editing, C.T.L., S.L.P., Z.G. and D.T.G.; visualization, X.J.; supervision, C.T.L., S.L.P. and D.T.G.; project administration, J.L.M.; funding acquisition, D.T.G. All authors have read and agreed to the published version of the manuscript.
Funding
C.T.L.: S.L.P., J.L.M., Z.G. and D.T.G. receive salaries from an unrestricted research grant from Medela AG (Switzerland) and administered by The University of Western Australia. X.J. is supported by UWA–China Scholarship Council (CSC) Joint PhD Scholarship and UWA–CSC Higher Degree by Research Top-Up Scholarship.
Institutional Review Board Statement
The study was conducted in accordance with the Declaration of Helsinki and was approved by The University of Western Australia Human Research Ethics Committee (2019/RA/4/20/6134).
Informed Consent Statement
Informed consent was obtained from all subjects involved in the study.
Data Availability Statement
Data sharing is not applicable.
Conflicts of Interest
D.T.G. declares participation in the Scientific Advisory Board of Medela AG. C.T.L., S.L.P., J.L.M., Z.G, and D.T.G. are/were supported by an unrestricted research grant from Medela AG, administered by UWA. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
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