May 17, 2007:
Childhood environment influences the female
reproductive function, a recent research has
The study, led by researchers at University
College, London (UCL), suggests that there is a
vital window of time from about 0-8 years of age
that establishes the rate at which girls
physically grow and how high their reproductive
hormone levels reach as adults.
The UCL study, published on May 15, 2007, in PLoS
Medicine, compares reproductive hormone levels of
groups of Bangladeshi women who migrated at
different periods of their life.
It was found that women who migrated from
Bangladesh to the United Kingdom in their babyhood
and early childhood reach puberty earlier, are
taller, and have up to 103% higher levels of the
hormone progesterone as adults, compared with
women who migrated at a later age, as well as
those who had remained in Bangladesh.
These higher hormone levels could potentially
enhance a woman’s capacity to conceive.
Dr Alejandra Núñez de la Mora of the UCL
Department of Anthropology and lead author of the
study says that the findings point to the period
before puberty as a sensitive phase when changes
in environmental conditions positively impact on
key developmental stages. In other words, the
female body seems to monitor its environment
throughout childhood and before puberty in order
to gauge when and at what rate it will be best to
mature. The body then sets development, including
reproductive hormone levels, accordingly.
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 – that is, when they are under less
physical strain because of favourable factors like
better diet and general health. When energy is a
limited resource, it is allocated between
maintenance, growth, and reproductive functions.
When conditions are better, more energy is
diverted towards reproduction, Dr Alejandra says.
The results of the study are significant not only
to Bangladeshi groups but also other groups and
populations in transition worldwide. And, these
findings add to evidence that humans have a
developed ability to react to constant
environmental conditions during growth and to make
decisions about how to allocate energy between
reproductive and other bodily functions.
Five groups of women were selected and compared
for the study – women who had matured in
Bangladesh but migrated to the UK as adults, those
who had moved to the UK as children,
second-generation Bangladeshi women living in the
UK, women who were born and raised in Bangladesh,
and a comparison group of women of European
descent who were born and raised in the UK.
Bangladeshi migrants were selected for this study
because of the elongated and on-going history of
migration to the United Kingdom and the general
disparity in conditions between the two countries.
According to Dr Gillian Bentley of the UCL
Department of Anthropology, who directed the
project, this is the first study to have used
measurements of hormone levels to demonstrate a
link between childhood environment and
reproductive maturation and function. The
potential health implications are far-reaching,
since a significant increase in progesterone
levels in migrant women may result, for example,
in higher breast cancer risks in subsequent
generations of this community.
Bangladesh, one of the most thickly populated
countries in the world, generally has poor hygiene
and its citizens have inadequate access to
healthcare – resulting in the slower development
of Bangladeshi women who grow up in the country.
BY OUR PHARMA CORRESPONDENT