Your Unborn Baby Catches Your Yawns

Fetuses yawn in the womb. Scientists have known this for a while. What they did not know, until now, is that a fetus can catch a yawn from its mother before it has ever seen a human face.

Researchers report in a study published May 5 in the journal Current Biology that pregnant women can spread yawns to their unborn offspring. The study recruited 38 women between 28 and 32 weeks pregnant and had them watch three types of videos: people yawning, people opening and closing their mouths, and people with still faces. Ultrasound captured what the fetuses were doing throughout.

About 64 percent of the women yawned during the yawn clips, and about 53 percent of their fetuses yawned as well, compared to almost no response during the other videos. The timing was not random. Fetuses were more likely to yawn after their mothers yawned, with a delay of roughly 90 seconds.

The fetus isn't catching the yawn by watching its mother's face. The researchers think the physical pressure of a maternal yawn or shifts in shared hormones may be transmitting the signal. Fetuses are already sensing and responding to the subtle mechanical and chemical changes of the body around them.

The findings suggest social attunement doesn't begin at first eye contact. It may begin weeks before birth.

Social bonding, it turns out, does not wait for a birth certificate.

Read the full story at Smithsonian Magazine, May 14, 2026

Hot Take: Mothers' bodies have been running a group chat with their babies since before language existed. Mom probably could have predicted "contagious prenatal yawning" without the study.