Even when a fetus's lungs are fully developed, it's impossible for the fetus to breathe until after birth. Developing babies are surrounded by amniotic fluid, and their lungs are filled with this fluid. By 10–12 weeks of gestation, developing babies begin taking practice breaths.
Do babies breathe before birth?
Although babies do practice breathing movements in the womb to train their muscles, they don't actually breathe in oxygen and breathe out carbon dioxide like you do. Instead, oxygen and carbon dioxide exchange happen via the umbilical cord and placenta.
What happens when baby takes first breath?
The first few breaths your baby takes may be shallow and irregular but they will soon become deeper and regular as you baby adjusts to breathing on their own. At this point, your baby's lungs, which were filled with fluid during pregnancy, must suddenly fill with oxygen from the air.
Do babies breathe before the umbilical cord is cut?
Most babies will start breathing or crying (or both) before the cord is clamped. However, some babies do not establish regular breathing during this time.