The question every mom-to-be gets asked a million times by family, friends and even strangers: "Do you know what you’re having?" Before the ultrasound was invented, myths abounded about what the sex of a baby could be by the way the mother was carrying the child in the womb. If the baby was sitting high, it was a girl. Carrying low? It’s probably a boy.
Now, there’s a way you maybe able to tell the sex of your baby even before conception: your blood pressure.
A new study published in The American Journal of Hypertension says that blood pressure could be a factor in determining the gender of a child.
Researchers followed 1,411 newly wed women in China and measured their triglycerides, blood pressure, cholesterol and glucose levels before pregnancy and at about 26 weeks into their pregnancies. Of the babies born during the study, 739 were boys and 672 were girls.
Mothers with high blood pressure were 1.5 times more likely to have a boy, the study found.
The research found that women who have hypertension—normally caused by a diet that’s high in salt, smoking or drinking too much—are more likely to give birth to boys. And, these findings also appeared to be true after accounting for the mother’s age, BMI, education and smoking habits.
However, the reverse is also true. Women who do not suffer from hypertension are more likely to have girls—although experts say they still don’t know why.
“In humans, the sex of the fetus is determined by the sex chromosome of the fertilizing sperm,” says study author Dr. Ravi Retnakaran. He says a mother’s blood pressure has never before been used as a determining factor for finding out the sex of a baby.
Retnakaran says there’s a warning with these findings, though. He cautions that the study results should not be used in societies that favor one sex over the other to purposely try to conceive a boy, noting that a mother’s blood pressure could be manipulated with medication.
And, the study results could explain why there are more girls born than boys in healthier countries.