A Woman's Blood Pressure Pre-Pregnancy May Predict Her Baby's Sex

It's no crystal ball, but it could be a new clue into how our physiology works.
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If the internet and old wives’ tales are to be believed, there are endless ways to predict the sex of your baby prior to the 20-week ultrasound. Are you carrying low? Craving sweet or salty foods? What does the ring and needle test say?

Of course, none of those are accurate.

But a provocative new study suggests there might be an easily identifiable physiological marker that predicts whether a woman is more likely to be carrying a boy or girl: Her blood pressure before pregnancy.

In the study, women who had boys tended to have higher systolic blood pressure prior to pregnancy (106 mmHg) than women who had girls (103 mmHg).

And while researchers say it shouldn’t be viewed as any kind of crystal ball just yet, they argue that the strong relationship between maternal blood pressure before pregnancy and a baby’s sex offers new hints about how human biology works.

In the study, published in the American Journal of Hypertension on Thursday, researchers tracked a group of more than 1,400 women in China before pregnancy and after, testing their blood pressure, triglycerides, cholesterol and glucose levels.

“What we asked here was, ‘Were there physiologic characteristics of the mother prior to the pregnancy that related to her likelihood of having a boy or girl?’” study author Dr. Ravi Retnakaran, an endocrinologist at Mount Sinai Hospital in Toronto, told The Huffington Post.

“The only thing that was related was blood pressure,” he continued, “but blood pressure was strongly related.”

“I think the way to look at this is that it may be telling us something very new about [our] physiology.”

- Dr. Ravi Retnakaran

What this all suggests, the researchers contend, is that a mother’s blood pressure before pregnancy is likely a marker of something in her physiology that makes her more likely to successfully carry a boy or girl to term. It is not, however, a causal relationship.

“One of the things we don’t want is for people to look at this and think, ‘Oh, we can manipulate the blood pressure before pregnancy and thereby change the chances of having a boy or a girl.’ We definitely are not saying that, because we are not showing cause and effect,” Retnakaran said. “Moreover, we don’t believe it’s cause and effect. We think it’s a marker of the underlying physiology.”

In other words, mothers-to-be certainly shouldn’t be scouring their pre-pregnancy medical charts in order to try and glean what their baby’s sex is ― for now.

At this point, the findings are simply interesting because they may be revealing something new and interesting about human biology, and something researchers need to continue to explore.

“I think the way to look at this,” Retnakaran said, “is that it may be telling us something very new about [our] physiology.”

Before You Go

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