Birth weight is a robust predictor of valued life course outcomes, emphasizing the importance of prenatal development. But does birth weight act as a proxy for environmental conditions in utero, or do biological processes surrounding birth weight themselves play a role in healthy development? To answer this question, we leverage variation in birth weight that is, within families, orthogonal to prenatal environmental conditions: one’s genes. We construct polygenic scores in two longitudinal studies (Born in Bradford, N = 2008; Wisconsin Longitudinal Study, N = 8488) to empirically explore the molecular genetic correlates of birth weight. A 1 standard deviation increase in the polygenic score is associated with an ~100-grams increase in birth weight and a 1.4 pp (22 percent) decrease in low birth weight probability. Sibling comparisons illustrate that this association largely represents a causal effect. The polygenic score–birth weight association is increased for children who spend longer in the womb and whose mothers have higher body mass index, though we find no differences across maternal socioeconomic status. Finally, the polygenic score affects social and cognitive outcomes, suggesting that birth weight is itself related to healthy prenatal development.

中文翻译：

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利用遗传数据探索胎儿起源假说


出生体重是有价值的生命历程结果的有力预测指标，强调了产前发育的重要性。但是，出生体重是否可以代表子宫内的环境条件，或者围绕出生体重的生物过程本身是否在健康发育中发挥作用？为了回答这个问题，我们利用出生体重的变化，即家庭内部与产前环境条件（基因）正交的变化。我们在两项纵向研究（出生于布拉德福德，N = 2008；威斯康星州纵向研究，N = 8488）中构建了多基因评分，以实证探索出生体重的分子遗传相关性。多基因评分增加 1 个标准差，出生体重增加约 100 克，低出生体重概率减少 1.4 个百分点（22%）。兄弟姐妹的比较表明，这种关联在很大程度上代表了因果效应。尽管我们发现母亲的社会经济地位没有差异，但在子宫内停留时间较长且母亲体重指数较高的孩子，多基因评分与出生体重的关联性增加。最后，多基因评分影响社会和认知结果，表明出生体重本身与健康的产前发育有关。