Genes Help Baby Girls Survive Preterm Birth

Genes in the placenta help baby girls survive a complicated birth, a new study finds.

The University of Adelaide research explains why baby girls have fewer health risks after a preterm birth.

A preterm birth is when a baby is born before the 37th week of pregnancy. Each year, some 500,000 babies are born preterm in the U.S., which is about 1 of every 8 infants born in the country. Research has shown that boys are at a higher risk of disability or even death due to preterm birth.

Researchers found that male and female babies grow differently and the placenta plays a critical role in improving girls' health outcomes.

"Our research has found that there are undeniable genetic and physiological differences between boys and girls that extend beyond just the development of their sexual characteristics," said Professor Claire Roberts, senior author of the paper and leader of the fetal growth research priority for the Robinson Research Institute.

For the study, researchers looked at how genes in the placenta were being activated and whether their expression was contributing to a girl child's survival. The research was based on 300 placenta samples. The team found that activity of at least 140 genes was different in male and female babies.

"We found that with female babies, there is much higher expression of genes involved in placental development, the maintenance of pregnancy and maternal immune tolerance. This suggests that girls are more likely to adopt a risk-averse strategy towards development and survival, and it goes some way to explaining the differences in male and female development in the womb," said Sam Buckberry, lead author of the study, in a news release.

The study could help design treatments that could help increase chances of male babies surviving preterm birth.

Preterm birth is associated with several short and long-term health complications such as poor cardiovascular function and brain disabilities.

The study is published in the journal Molecular Human Reproduction.