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Fetal Heart Rate for Gender Prediction

As the old wives' tale has it, if your unborn baby's heart rate is higher, above 140 beats per minute, that means you're carrying a girl. A lower heart rate below 140 bpm means you're having a boy.

It's hard to resist such an easy test, and ever so tempting to over-analyze the pitter patter of that tiny heart. In early pregnancy, the reassuring sound of that heartbeat is just about the only thing we've got to show a baby's even there.

But don't get your hopes up, or have your hopes dashed, based on your baby's heart rate, because it has absolutely nothing to do with what your baby has between its legs. This particular old wives' tale was found to be completely false by a medical study decades ago; another medical study in 2006 confirms that fetal heart rate has nothing to do with the baby's sex, and even more convincing, Maureen has even conducted her own in-womb experiment to prove it.

Two Medical Studies Disprove Fetal Heart Rate for Gender Prediction

In the 1980s, a senior sonographer analyzed thousands of births to determine whether fetal heart rate could predict a baby's sex. (See link to study below.) After measuring 10,000 fetal heart rates, and following up to find out the baby's gender at birth, it was clear that there was no correlation between the baby's heart rate at any point throughout pregnancy with the baby's sex.

Fetal Heart Rate and Baby Gender

The study did find a relationship between the baby's heart rate and gestational age (weeks of pregnancy).

In 2006, another study published in Fetal Diagnosis and Therapy, tells us that analysis of over 500 births proves again that fetal heart rate cannot predict whether a baby is a boy or a girl.

Contrary to beliefs commonly held by many pregnant women and their families, there are no significant differences between male and female fetal heart rate during the first trimester.
-- Study in Fetal Diagnosis and Therapy

Maureen Goes The Extra Mile

Sure, that's all quite convincing data, but still I decided to conduct my own experiment to see if fetal heart rate could indicate a baby's gender. To do my experiment, first I became pregnant with boy/girl twins. Then, I underwent a LOT of fetal heart monitoring, including one week of almost constant monitoring while hospitalized for preterm labor, as well as twice-weekly non-stress tests in which both babies heart rates were tracked for 30 minutes. (You can see I am quite dedicated to the interests of science.)

The result? Sometimes the boy's heart rate was higher, sometimes the girl's heart rate was higher. No pattern, except that when one of the babies seemed to be more active, kicking and moving around alot, that baby's heart rate would tend to be higher. It makes sense, that a baby's heart rate might vary a good bit depending on whether it's active or at rest at the time the heart rate is checked.

So the next time you see a post in a pregnancy forum from a mother "proving" this theory is right because her two girls had high heart rates and her three friends had boys with low heart rates, you can set the record straight on this old wives' tale: it's false.