A woman's fertility could be influenced by her childhood experiences, according to a new study by researchers based at University College London. Their findings, published in the journal PloS Medicine, suggest that there is a critical period from birth up to eight years of age that could affect their ability conceive later in life.
The study looked at levels of reproductive hormones in groups of Bangladeshi women who emigrated to the UK at different times of their lives. They found that those who migrated during infancy and early childhood reached puberty earlier and had higher levels of the hormone progesterone, compared to women who remained in Bangladesh, and also those who migrated at a later age. Higher hormone levels could potentially increase a woman's chances of conceiving, say the scientists.
Lead author Dr Alejandra Nunez de la Mora says that the study suggests that the period before puberty is a key time, during which environmental changes can affect later developmental stages. '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', he said, adding 'in other words, when they're under less physical strain due to factors like a better diet and general health'.
The findings add to evidence that humans have evolved to monitor their environment throughout childhood, to gauge when conditions are good enough to divert energy on reproducing. Gynaecologist Adrian Lower described this conclusion as 'a reasonable idea', adding that it 'suggests evidence to support the fact that improved nutrition is likely to have a beneficial effect on fertility'.
The team studied five different groups of women living in Bangladesh and the UK, and looked at levels of the hormones progesterone and oestradiol over an extended period. Co-author Dr Gillian Bentley pointed out that the increased hormone levels in some of the migrants might also have unwelcome effects on health - such as higher rates of breast cancer in subsequent generations of the UK Bangladeshi community.