Childhood years impact fertility

Early environment could influence women's fertility

The conditions in which females are brought up could affect their fertility later in life, research suggests.

Researchers at University College London monitored hormone levels in women who migrated to the UK from Bangladesh at different stages in life.

Women who had spent their childhood in the healthier conditions of the UK had higher levels of reproductive hormones than those brought up in Bangladesh.

The findings were published in the journal PLoS Medicine.

The team said in the UK women would have access to better sanitation and health care, and less risk of disease.

They found women who had spent their early childhood in the UK reached puberty earlier and had up to 103% higher levels of the hormone progesterone as adults, compared with those who migrated later or did not migrate at all.

The increase in progesterone levels may result in higher breast cancer risks in subsequent generations Dr Gillian Bentley

These higher hormone levels could increase a woman's ability to conceive.

But author Dr Gillian Bentley said the observed hormone levels might also have some negative health impacts.

She said: "The significant increase in progesterone levels that we document in migrant women may result, for example, in higher breast cancer risks in subsequent generations of this community."

Critical period

The finding suggests that early childhood is critical in determining the rate at which girls mature and how high their reproductive hormone levels are as adults.

Lead researcher Dr Alejandra Núñez de la Mora said girls who migrated early in life seemed to mature more quickly.

This could be because they were living in an environment where they had access to a better diet and general health.

He said the female body could monitor its environment throughout childhood to gauge when and at what rate it would be best to mature.

Evolutionary Advantage

He said: "This is an advantage in evolutionary terms, as it makes the best of the resources and energy available for reproduction in any given circumstance."

This would make sense because when energy is limited it must be shared between all bodily functions, so when conditions are better more can be diverted to reproduction.

Five groups of women were compared in the study, including those who grown up in Bangladesh but moved to the UK as adults, those who had moved as children and others who were born in either England or Bangladesh and remained there.

Mr Adrian Lower, a consultant gynaecologist, said: "This sounds like a reasonable idea and suggests evidence to support the fact that improved nutrition is likely to have a beneficial effect on fertility."