Department of Clinical and Experimental Medicine, Linköping University, Linköping 58185, Sweden.
Charles Perkins Centre-Nepean, Sydney Medical School-Nepean, The University of Sydney, Penrith, New South Wales 2751, Australia.
Proc Biol Sci. 2021 Jan 13;288(1942):20202329. doi: 10.1098/rspb.2020.2329.
Animal studies have shown that maternal resource allocation can be sex-biased in order to maximize reproductive success, yet this basic concept has not been investigated in humans. In this study, we explored relationships between maternal factors, offspring sex and prenatal and postnatal weight gain. Sex-specific regression models not only indicated that maternal ethnicity impacted male ( = 2456) and female ( = 1871) childrens postnatal weight gain differently but also that parity and mode of feeding influenced weight velocity of female ( ± s.e. = -0.31 ± 0.11 kg, = 0.005; ± s.e. = -0.37 ± 0.11 kg, < 0.001) but not male offspring. Collectively, our findings imply that maternal resource allocation to consecutive offspring increases after a male firstborn. The absence of this finding in formula fed children suggests that this observation could be mediated by breast milk. Our results warrant further mechanistic and epidemiological studies to elucidate the role of breastfeeding on the programming of infant growth as well as of metabolic and cardiovascular diseases, with potential implications for tailoring infant formulae according to sex and birth order.
动物研究表明，母体资源分配可以存在性别偏向，以最大限度地提高繁殖成功率，但这一基本概念尚未在人类中得到研究。在这项研究中，我们探讨了母体因素、后代性别与产前和产后体重增加之间的关系。性别特异性回归模型不仅表明，母亲的种族会影响男婴（ = 2456）和女婴（ = 1871）的产后体重增加，而且生育次数和喂养方式也会影响女婴（ ± s.e. = -0.31 ± 0.11 kg， = 0.005； ± s.e. = -0.37 ± 0.11 kg， < 0.001）的体重增长速度，但对男婴没有影响。总的来说，我们的研究结果表明，母亲对连续出生的后代的资源分配会在第一个男婴出生后增加。配方奶喂养的婴儿中没有这种现象，这表明这种观察可能是由母乳介导的。我们的研究结果需要进一步的机制和流行病学研究来阐明母乳喂养在婴儿生长编程以及代谢和心血管疾病中的作用，这可能对根据性别和出生顺序定制婴儿配方奶粉具有潜在意义。
