American journal of human biology : the official journal of the Human Biology Council
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The association between a woman's age at menarche and the birth weight of her children is highly variable across human populations. Life history theory proposes that a woman's early environment may moderate this association and thus account for some of the variation between populations. According to one life history theory model, for individuals who develop in a childhood environment of high local mortality rates (experienced subjectively as psychosocial stress), it can be adaptive to mature earlier, have more offspring during their reproductive lifetime, and reduce investment in each offspring. ⋯ We found that earlier menarche in those women who experienced stressful life events before 15 years of age was associated with a lower birth weight and proportionate birth weight. Conversely, in those who reported no childhood stressors, earlier menarche was associated with increased birth weight and proportionate birth weight. Our data suggest that the moderating influence of the childhood psychosocial environment on the association between age at menarche and parental investment throughout gestation operates in a dose-dependent manner.