Differential Relationships Between Chronic Hormone Profiles in Pregnancy and Maternal Investment in Rhesus Monkey Mothers With Hair Loss in the Neonatal Period

The study examined 47 female rhesus monkeys, focusing on a subset of 26 during mid-to-late pregnancy through peak lactation, to explore the relationship between hair loss and chronic hormone profiles, specifically hair cortisol concentrations (HCCs), and their impact on maternal investment. It was found that monkeys with hair loss had significantly higher HCCs during pregnancy than those without. Additionally, in monkeys with hair loss, higher HCCs were associated with heavier birth weights, faster infant growth rates, and greater milk yield volume, suggesting that these mothers may experience greater physiological stress during pregnancy and invest differently in their offspring. This relationship was not observed in mothers without hair loss. The study suggests that hair loss in pregnant rhesus monkeys may be an indicator of increased physiological stress and could influence maternal investment strategies.