Can You Predict a Baby's Gender from the Heartbeat? The Medical Truth
The moment you find out you are pregnant, the speculation begins. Friends, family, and strangers in the grocery store will all try to guess the gender of your baby based on how you look, what you eat, and how you feel.
One of the most persistent "old wives' tales" is that you can predict the baby's sex based on the fetal heart rate during an early ultrasound.
The Heartbeat Theory
The myth claims that female fetuses have faster heart rates than male fetuses.
- Over 140 beats per minute (BPM) = Girl
- Under 140 beats per minute (BPM) = Boy
It sounds plausible. After all, adult women generally have slightly faster resting heart rates than adult men. Does this apply to fetuses in the womb?
What the Science Says
Medical researchers have actually conducted massive, peer-reviewed studies to put this myth to the test once and for all.
In a comprehensive study published in the journal Fetal Diagnosis and Therapy, researchers analyzed the sonograms of nearly 10,000 pregnancies during the first trimester.
The results? There is absolutely no statistically significant difference in heart rate between male and female fetuses. The average heart rate for girls was 151.7 bpm, and the average for boys was 154.9 bpm. The myth is completely busted.
Why Does the Heartbeat Fluctuate?
A fetal heart rate changes drastically based on two things: gestational age and fetal activity.
At 6 weeks pregnant, the heart is just starting to beat and is usually around 100-120 BPM. It peaks at 9 weeks (often hitting 170 BPM), and then slowly decreases to around 130-150 BPM for the remainder of the pregnancy.
Furthermore, just like you, a baby's heart rate spikes when they are moving around and drops when they are sleeping!
If you want to know exactly what gestational week your baby is currently in, use our Pregnancy & Due Date Calculator to track their current developmental stage. But if you want to know the gender, you'll have to wait for the NIPT blood test or the 20-week anatomy scan!
Track your health accurately: Try our free Pregnancy & Due Date Calculator to get instant, personalized medical math for your pregnancy journey.