CAMBRIDGE, England — Many expecting couples often choose to wait until birth to learn their child’s sex so they can revel in the ultimate surprise. New research suggests, however, that it’s actually wiser for parents to know the baby’s sex as soon as possible. That’s because doctors say parents can be better equipped to protect their unborn child and themselves from potential pregnancy problems.
Babies who are biologically male tend to have more pregnancy complications than girls because they grow faster and need more nutrients or oxygen from the placenta.
“We’re now building more and more evidence of what to measure in the mum in pregnancy like her starting body mass index, her growth, her gestational weight, but also considering fetal sex. Routinely, clinicians do consider sex when they’re looking at ultrasound images, because sex is an important determinant of how the fetus is growing,” says Amanda Sferruzzi-Perri, a Fellow of St John’s College, at the Centre for Trophoblast Research in a statement. “However, we’ve not really understood before how that might be determined; how that might be interacting with the environment of the mother or the way in which the pregnancy is occurring. So our studies are giving more information to the clinician to provide more informed decisions about how to manage that pregnancy.
One in 10 women has life-threatening pregnancy problems. However, many of these conditions are treatable if they are caught on time. “Often parents don’t want to know the baby’s sex because they want it to be a surprise. But actually knowing the sex would help to identify whether a pregnancy may be at greater risk than another because we know that some conditions of pregnancy such as pre-eclampsia and fetal growth restriction can be more prevalent in women that carry male babies than females.” The results of the current study suggest knowing the sex could have lifelong health benefits for the baby.
A second study that accompanies the current results showed that diet-induced obesity during pregnancy affects the structure of the placenta and causes issues with baby growth. The changes vary depending on the sex of the fetus.
“The placenta has an amazing skill in changing how it forms and how it functions,” explains Dr. Sferruzzi-Perri. “This can be seen at multiple levels from the way in which the cells form in the placenta, it’s genes and proteins, even its mitochondria. These can all change in response to different types of cues, whether it’s in a mother that has been eating a sugary, fatty diet, or in a pregnancy where there is rivalry between the siblings when there’s more than one baby, but what I think is probably the most novel aspect is that the way the placenta does adapt seems to depend on whether the baby’s female or male.”
Both studies indicate there is a high need for creating sex-specific therapies to deal with placenta problems and fetal growth abnormalities. Additionally, preventative measures such as interventions aimed at reducing obesity in pregnancy are warranted.
The findings may also help understand how early life conditions affect the risk for diseases such as Type 2 diabetes and heart disease. Both diseases are sex-dependent with males having a higher rate of developing them. Current research is underway using a mouse model of obesity.
The study is published in the journal Biology of Reproduction.