Presented at the Neonatal Society 2011 Autumn Meeting.
Koo M, Jeffries S, Hyde MJ, Gale C, Santhakumaran S, Modi N
Section of Neonatal Medicine, Department of Medicine, Imperial College London, Chelsea & Westminster campus, London, SW10 9NH
Background: Maternal health may influence neonatal outcomes through breast milk (1). We have shown that maternal BMI is a highly significant influence upon newborn adiposity and hepatic lipid (2). As part of a student project linked to our wider research programme, we aimed to test the hypothesis that the hormonal composition of breast milk is affected by maternal BMI.
Methods: With Research Ethics Committee approval (08/H0711/43), healthy mothers from across the BMI range, delivering at term, were recruited from the post-natal wards at Chelsea & Westminster Hospital. Maternal BMI at booking was retrieved from medical records. Foremilk samples were collected during the first 2 weeks post-partum by hand expression prior to suckling. A 200μl aliquot of milk was centrifuged at 4000rpm for 20 minutes, fat was removed and the skimmed milk used for analyses. Milk hormone content was analysed, following manufacturers‟ instructions, using commercially available kits for ghrelin: (Human Ghrelin (Active), ELISA kit, Millipore, UK), leptin (Human Leptin, ELISA kit, Millipore, UK), obestatin (Human Obestatin EIA, Stratech, UK). We aimed to recruit 60 mothers across the BMI range to achieve power to detect correlations likely to be clinically relevant. Data were analysed using SPSS (version 19).
Results: During the time available for this student project milk samples were obtained from 24 mothers (booking BMI range 19 to 49 kg.m-2 (table1).
Table 1: All values presented as mean ± SD, unless otherwise stated
Obestatin was detectable in all milk samples; the range of leptin and ghrelin concentrations was wide and included undetectable levels (table 2). We found no statistically significant relationship between breast milk hormone content and maternal BMI (Spearman’s p: leptin = 0.203 (95%CI -0.239 to 0.575; p=0.36); ghrelin = 0.124 (95%CI -0.314 to 0.519; p=0.58); obestatin = 0.081 (95%CI -0.343 to 0.477; p=0.71). Maternal diabetes, mode of delivery and sex of the baby also had no discernable effect on the concentrations of these hormones (Mann-Whitney U test).
Table 2: All values presented as mean ± SD, unless otherwise stated
Conclusion: We have confirmed the presence of adipokines in wide concentration in human milk. We found no association between maternal BMI and breast milk concentration of ghrelin, leptin and obestatin. Our findings are inconclusive given the limited sample size to date but we note that the very small number of published studies on breast milk ghrelin and leptin report both positive and negative associations with maternal BMI. This is one of the first studies to report on the concentration of breast milk obestatin. Our continuing work aims to relate breast milk hormone content to maternal characteristics and ultimately to evaluate their importance to newborn physiology.
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1. Plagemann A et al Diabetes Care 2002; 25:16-22
2. Modi N et al Pediatr Res 2011; 70:287-91