A study led by researchers at UCL (University College London) demonstrates that female reproductive function is influenced by childhood environment. This suggests there is a critical window of time from about 0-8 years of age that determines the rate at which girls physically mature and how high their reproductive hormone levels reach as adults.
Published today in PLoS Medicine, the study compares reproductive hormone levels of groups of Bangladeshi women who migrated at different periods of their life. It finds that women who migrated from Bangladesh to the UK during infancy and early childhood reach puberty earlier, are taller, and have up to 103 per cent higher levels of the hormone progesterone as adults in comparison to women who migrated at a later age, as well as those who had remained in Bangladesh. These higher hormone levels could potentially increase a womans ability to conceive.
Lead author Dr Alejandra Nez de la Mora, UCL Department of Anthropology, said: "The findings point to the period before puberty as a sensitive phase when changes in environmental conditions positively impact on key developmental stages. Put very simply, the female body seems to monitor its environment throughout childhood and before puberty, to gauge when and at what rate it will be best to mature. It then sets development, including reproductive hormone levels, accordingly. This is an advantage in evolutionary terms, as it makes the best of the resources and energy available for reproduction in any given circumstance.
"Girls who migrate at a young age seem to mature more quickly when they find themselves in an environment where the body has more access to energy. In other words, when theyre under less physical strain due to factors like a better diet and general health. When energy is a limited resource, it must be allocated between maintenance, growth, and reproductive functions the body makes trade-offs within the constraints it experiences.
Contact: Ruth Metcalfe
University College London