Babies do not exactly “breathe” in the womb; at least not by inhaling air they way they do after delivery. Instead, oxygen travels through the mother's lungs, heart, vasculature, uterus, and placenta, finally making its way through the umbilical cord and into the fetus.

How do babies breathe in the womb without drowning?

Fast facts on how babies breathe in the womb:

The umbilical cord is the main source of oxygen for the fetus. As long as the umbilical cord remains intact, there should be no risk of drowning in or outside the womb.

When do fetal breathing movements start?

In the human species, foetal breathing movements are detectable from the fifteenth week of gestation and their incidence increases until the start of the third trimester. Over the last 10 weeks, breathing movements are present for 30% of the time.