Boy or girl?

Does a heart rate over 140 mean it’s a girl?

Checked against the sources listed on this page. Not reviewed by a clinician. Last updated 5 November 2026. How we check.

Myth

No. Studies comparing early heart rates in boys and girls found no meaningful difference. Heart rate depends mostly on gestational age.

A baby’s heart rate climbs from about 100–120 bpm at 6 weeks to a peak near 170–180 bpm at 9–10 weeks, then settles to 110–160 bpm. That age-related swing is far bigger than any difference between the sexes.

Heart rate also changes minute to minute with activity and sleep, so one reading can’t predict anything.

References

  1. McKenna DS et al. Gender-related differences in fetal heart rate during first trimester. Fetal Diagnosis and Therapy, 2006
  2. Papaioannou GI et al. Normal ranges of embryonic length and heart rate. Fetal Diagnosis and Therapy, 2010

Related weeks

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More boy or girl? myths

Myth

Does carrying high mean a girl and carrying low mean a boy?

No. The shape and height of a bump depend on your muscles, body shape, how many pregnancies you’ve had and the baby’s position, not the baby’s sex.

 Partly true

Does bad morning sickness mean you’re having a girl?

There’s a small statistical link between severe sickness and girls, but it can’t predict the sex of any one baby.

 Myth

Do sweet cravings mean a girl and salty cravings a boy?

No. There’s no evidence cravings relate to the baby’s sex. They are shaped by hormones, culture, habit and changes in taste and smell.