Effects of Seasonality and Pregnancy on Hair Loss and Regrowth in Rhesus Macaques

February 2024 in “ Animals ”

Allison Heagerty, Rebecca Wales, Kristine Coleman

alopecia hair loss hair regrowth seasonal pattern pregnancy postpartum hormonal factors

TLDR Hair loss peaks in spring and regrowth in late summer, with pregnant females losing the most hair.

This study on 241 rhesus macaques over one year found that hair loss (alopecia) was most severe in pregnant females, especially during the birthing season in spring, and least severe in males and nonpregnant females. Hair regrowth followed a seasonal pattern, peaking in summer, with pregnant females showing delayed regrowth until postpartum. The findings indicate that both reproductive status and seasonal changes significantly influence hair loss and regrowth, with hormonal factors likely inhibiting regrowth during pregnancy.

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Research cited in this study

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