Department of Anthropology, Emory University, Atlanta, Georgia, USA.
Am J Hum Biol. 2010 Jul-Aug;22(4):431-43. doi: 10.1002/ajhb.21014.
Sex differences in fetal growth have been reported, but how this happens remains to be described. It is unknown if fetal growth rates, a reflection of genetic and environmental factors, express sexually dimorphic sensitivity to the mother herself. This analysis investigated homogeneity of male and female growth responses to maternal height and weight. The study sample included 3,495 uncomplicated singleton pregnancies followed longitudinally. Analytic models regressed fetal and neonatal weight on tertiles of maternal height and weight, and modification by sex was investigated (n = 1,814 males, n = 1,681 females) with birth gestational age, maternal parity, and smoking as covariates. Sex modified the effects of maternal height and weight on fetal growth rates and birth weight. Among boys, tallest maternal height influenced fetal weight growth before 18 gestational weeks of age (P = 0.006), and prepregnancy maternal weight and body mass index subsequently had influence (P < 0.001); this was not found among girls. Additionally, interaction terms between sex, maternal height, and maternal weight identified that males were more sensitive to maternal weight among shorter mothers (P = 0.003) and more responsive to maternal height among lighter mothers (P < or = 0.03), compared to females. Likewise, neonatal birth weight dimorphism varied by maternal phenotype. A male advantage of 60 g occurred among neonates of the shortest and lightest mothers (P = 0.08), compared to 150 and 191 g among short and heavy mothers, and tall and light-weight mothers, respectively (P = 0.01). Sex differences in response to maternal size are under-appreciated sources of variation in fetal growth studies and may reflect differential growth strategies.
胎儿生长存在性别差异，但具体机制尚不清楚。目前还不知道胎儿生长速度（反映遗传和环境因素）是否会表现出对母体自身的性别二态敏感性。本分析旨在探讨男性和女性对母亲身高和体重的生长反应是否具有同质性。该研究样本包括 3495 例无并发症的单胎妊娠，并进行了纵向随访。分析模型将胎儿和新生儿体重与母亲身高和体重的三分位数进行回归，同时还探讨了性别对其的修饰作用（男性 n = 1814，女性 n = 1681），并将出生胎龄、母亲产次和吸烟作为协变量。性别修饰了母亲身高和体重对胎儿生长速度和出生体重的影响。在男孩中，最高的母亲身高会影响 18 孕周前的胎儿体重增长（P = 0.006），随后母亲孕前体重和体重指数也会产生影响（P < 0.001）；但在女孩中没有发现这种情况。此外，性别、母亲身高和母亲体重之间的交互项表明，与女性相比，男性在较矮和较轻的母亲中对母亲体重更敏感（P = 0.003），在较瘦和较轻的母亲中对母亲身高更敏感（P < 0.03）。同样，新生儿出生体重的二态性也因母亲表型而异。在最矮和最轻的母亲的新生儿中，男性的优势为 60 g（P = 0.08），而在较矮和较重的母亲、较矮和较轻的母亲以及较高和较轻的母亲的新生儿中，这一优势分别为 150 g 和 191 g（P = 0.01）。对母体大小的反应存在性别差异，这是胎儿生长研究中容易被忽视的变异来源，可能反映了不同的生长策略。
