Medieval menarche: changes in pubertal timing in the aftermath of the Black Death

OBJECTIVES: Bioarchaeological evidence suggests stature increased in males but decreased in females after the Black Death (1348-1350 CE). Because tradeoffs between growth and reproduction can result in earlier ages at menarche and lower limb length, we assess menarcheal age between 1120 and 1540 CE to better understand the health of medieval adolescent females before and after the plague. MATERIALS AND METHODS: Our sample comprises 74 adolescent females from St Mary Spital, London (1120-1540 CE) within the age range during which menarche occurs (10-25 years). They were assessed as being pre- or post-menarcheal and divided into three groups: Early Pre-Black Death (n=13), Late Pre-Black Death (n=38), and Post-Black Death (n=23). Changes in the ages of pre- and post-menarcheal females were assessed using Mann-Whitney tests. RESULTS: The average age of post-menarcheal females increased from the Early- to Late Pre-Black Death periods and declined after the Black Death. CONCLUSIONS: Short stature can reflect unfavorable growth environments, while younger menarcheal age indicates improved living conditions. The paradoxical pattern of female, but not male, stature reduction after the Black Death might reflect the association of early menarche with lower limb length and signal that adolescent females experienced improved health conditions after the epidemic. Our focus on pre- and post-menarche within a limited age span provides a novel approach for inferring average ages of menarche over time. Pathways to skeletal development and reproductive investment are part of an integrated system, providing a bridge between life history research in bioarchaeology and human biology