Overview

• Girls with menarche before 11 or women with first childbirth before 21 faced roughly double the risk of type 2 diabetes, heart failure, and obesity, and quadruple the risk of severe metabolic disorders.
• Genetic analyses identified 126 variants that appear to mediate these links, many tied to IGF-1, growth hormone, AMPK, and mTOR signaling.
• Later reproductive timing was genetically associated with longer lifespan, lower frailty, slower epigenetic aging, and reduced risk of type 2 diabetes and Alzheimer’s disease.
• Authors interpret the results as human evidence for antagonistic pleiotropy, suggesting traits favoring early reproduction carry later-life health costs.
• Researchers urge clinicians to factor reproductive history into prevention and screening, highlighting BMI as a key mediator and noting U.S. trends toward earlier menarche since the 1970s.