Can a mom's blood pressure predict the sex of her baby?

Jan 18, 2017 at 9:42 a.m. ET
Image: Katrinaelena/iStock/Getty Images Plus

We're all familiar with the old wives tales for predicting a baby's sex. They have absolutely no scientific backing, but hey, we still apply them anyway, right?

Well, now there's a new theory about predicting the sex of a baby – and it comes straight from the science lab (with nothing to do with IVF gender selection.) According to Canadian researchers, the key to determining whether you will have a boy or a girl lies with your blood pressure.

More: Taking micronutrient supplements during pregnancy may lead to smarter kids

The team at Mount Sinai Hospital in Toronto discovered that a woman’s blood pressure at around 26 weeks before conception predicts whether she will give birth to a boy or a girl. Higher systolic blood pressure suggests she will deliver a boy, while lower suggests a girl.

"When a woman becomes pregnant, the sex of a foetus is determined by whether the father’s sperm provides an X or Y chromosome and there is no evidence that this probability varies in humans," said Mount Sinai endocrinologist Dr. Ravi Retnakaran. "What is believed to vary is the proportion of male or female fetuses that is lost during pregnancy. This study suggests that either lower blood pressure is indicative of a mother’s physiology that is less conducive to survival of a male foetus or that higher blood pressure before pregnancy is less conducive to survival of a female foetus. This novel insight may hold implications for both reproductive planning and our understanding of the fundamental mechanisms underlying the sex ratio in humans."

More: I'm totally fine with my child being average

The 1,411 participants were all newly married Chinese women who were trying to get pregnant. Their blood pressure was checked at around 26 weeks before conception and they went on to give birth to 739 boys and 672 girls.

It's an interesting theory (and one that carries more weight than the old swinging a ring over your belly method). However, critics point out that further studies are required to determine whether potential physiological aspects of race play a role.

More: 11 early signs of pregnancy you shouldn't be ignoring

Comments