Anatomy

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How Powerful Are a Baby’s “Kicks” in the Womb?

Last Modified Date: February 22, 2024

Babies can be quite a kick -- literally. Although pretty much every expectant mother has felt the forceful footwork of her baby, the true force of those kicks might come as a surprise.

According to researchers at Imperial College London, a baby's kick can transfer about 10 pounds (4.8 kg) of force to its mother's womb. To put that in perspective, those powerful kicks pack twice the wallop of the force needed to serve a tennis ball at 100 mph (160 km/h).

In utero, a baby's kicks can produce around 10 lbs (4.8 kg) of force.

To arrive at their figures, the scientists analyzed MRI scans of fetuses in utero and used computer modeling to get an accurate measurement. The researchers also determined that the most powerful kicking typically occurs during weeks 20 through 30 of the pregnancy. After that, the fetus calms down -- mainly because there's less room to swing -- with the average kick bringing less than 4 pounds (1.8 kg) of force.

Those kicks are probably beneficial to the baby's bone and joint formation and are not just intended to add stress during pregnancy, the researchers noted.

View of a womb:

Besides kicking, babies in the womb begin to urinate at about the four-month point, and drink the urine a few weeks later.

Ultrasound has revealed that babies in the womb open their mouths, gasp, and cry.

Just in case your child wants to do some criminal activity upon arriving, remind him (or her) that fingerprints are completely formed by the 12th week of pregnancy.