Climate change and periods: Climate conditions may influence when girls start menstruating, with higher humidity linked to earlier menarche and higher temperatures tied to delays, according to a new analysis of Indian data published in PLOS Global Public Health.
Researchers from Bangladeshi institutes, including North South University, examined two rounds of India’s Demographic and Health Surveys (DHS), 1992–93 and 2019–21, alongside NASA climate records. The team analysed more than 23,000 responses from the early 1990s and 45,300 from 2019–21, comparing menarche timing across states over roughly 25 years.
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Overall, girls in most states were beginning menstruation at younger ages in the 2019 cohort than in the 1992 cohort, the study reports. An exception was Maharashtra, where the onset appeared to be delayed. Statistical models linked higher specific humidity with an earlier start to periods, while higher temperatures correlated with a later onset.
The authors note that shifts in age at menarche are part of a global pattern observed particularly since the latter half of the 20th century. Prior research has pointed to multiple drivers, from environmental exposures, climate and air pollution to nutrition and body mass index.
In this analysis, rising humidity was associated with an advance in menarche timing, potentially by altering underlying health conditions. Conversely, the temperature-related delay seen in Maharashtra may reflect physiological stress from chronic heat exposure, which can affect hormonal regulation and slow puberty, the researchers suggest.
Education also appeared to play a role: higher educational attainment was associated with earlier menarche, underscoring demographic influences alongside environmental ones.
The authors call for continued monitoring of climate–health interactions and for public-health measures that strengthen nutrition, healthcare access, and health education.
