A video showing an "en caul" birth has been widely shared on X (still aka Twitter) and Instagram, introducing a new batch of people to the fact that some babies are born inside their amniotic sacs.
The video, from an unknown source but shared first by kids.mood on Instagram, shows a baby wriggling around inside the amniotic sac while under the care of a medical team.
Inside the womb, a thin-walled sac surrounds the fetus, known as the amniotic sac. Usually, once labor has begun the sac ruptures and the amniotic fluid pours out, known as your water "breaking". Sometimes, this doesn't happen until late in labor, and healthcare professionals may break your waters for you, i.e. rupture the amniotic sac, in order to speed up labor.
Occasionally though, the sac doesn't rupture at all, an en caul birth. This can happen intentionally during a cesarean, or in rarer cases spontaneously during a vaginal delivery. Precise figures aren't known, but it's estimated that around 1 in 80,000 births occur like this.
En caul births are generally harmless, and the baby is easily removed by rupturing the sac, letting it slide out into the world. Oh, and it can happen in dogs too.