Thaindian News

Sydney, April 30 (IANS) Baby’s sex decides the way it responds to stress during pregnancy and its ability to survive complications, says a study.
Male and female babies show different growth and development patterns following stressors during pregnancy such as disease, cigarette use or psychological stress.

The research is being carried out by the Robinson Institute’s Pregnancy and Development Group, based at the Lyell McEwin Hospital and led by Vicki Clifton, associate professor at the University of Adelaide.

“What we have found is that male and female babies will respond to a stress during pregnancy by adjusting their growth patterns differently,” said Clifton.

“The male, when mum is stressed, pretends it’s not happening and keeps growing, so he can be as big as he possibly can be.

“The female, in response to mum’s stress, will reduce her growth rate a little bit; not too much so she becomes growth restricted, but just dropping a bit below average,” added Clifton.

“When there is another complication in the pregnancy - either a different stress or the same one again - the female will continue to grow on that same pathway and do okay but the male baby doesn’t do so well and is at greater risk of pre-term delivery, stopping growing or dying in the uterus.”

Clifton said this sex-specific growth response had been observed in pregnancies complicated by asthma, pre-eclampsia and cigarette use but was also likely to occur in other events such as psychological stress.

She said this sex-specific growth pattern was a result of changes in placental function caused by the stress hormone cortisol, said an Adelaide University release.

In female babies, increased cortisol produces changes to the placental function which lead to the reduction in growth, but the increased cortisol levels in a mother carrying a male baby doesn’t produce the same changes in placental function.

Clifton said this research could lead to sex-specific therapies in pre-term pregnancies and premature newborns. It was also important in helping obstetricians more accurately interpret growth and development of the foetus in at-risk pregnancies.