Environmental Changes In Fertility
How Your Body Adapts To Your Surroundings
A study in the UK reveals that a girl's fertility can increase and decrease according to her surroundings
Researchers at University College London, UK, led a study about female fertility which has suggested that a female's fertility levels may change in response to her environment.
It is known that the female reproductive system is a complex system where many things can potientially go wrong, even due to hormones or stress, but the study revealed that a girl's fertility can be affected by her surroundings. It is thought that the first 8 years of a girl's life can determine how fertile she is as an adult.
Researchers looked at the following groups of women:
- Bangladeshi women who were born and raised in the UK.
- Bangladeshi women who moved to the UK in childhood.
- Bangladeshi women who moved to the UK in adulthood.
- Bangladeshi women who remained in Bangladesh.
- A comparison group of women from other European countries, who had moved to the UK.
It was discovered that those born in the UK and those who had moved there during early childhood, go through puberty earlier, grow taller and have progesterone levels that are up to 103% higher than those who moved later on in life.
Dr. Alejandra Nunez de la Mora, from the UCL, 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 simply, the female body seems to monitor its environment throughout childhood and before puberty, to gauge when and at what rate it would be best to mature. It then sets development accordingly.'
Those who have access to good food, i.e. more energy, develop earlier and have more fertility hormones. When this energy is limited through lack of food and other factors, the body's main priority is to sustain itself (by feeding the heart, brain, digestive system etc.) so less energy is put towards the reproductive system.
In extreme conditions, a woman's period will be delayed or stop altogether. This is nature's way of ensuring there are no babies to feed when food is scarce.
This theory has been previously explored in the scientific community but it is the first time a link between childhood environment and future fertility has been found.
General health information, measurements and saliva samples were also taken from the women in the study. Progesterone levels influence many aspects of reproductive health, including the menstrual cycle, health during pregnancy and even how the embryo develops, so looking at diet and environment during childhood and lifestyle factors may be a key in understanding how fertility works.
PLOS Medicine, doi:10.1371/journal.pmed.0040167.
