3 doctors weighed in:

When a baby is in its mother's womb, how do the lungs breathe?

3 doctors weighed in
Dr. James Ferguson
Pediatrics
1 doctor agrees

In brief: They don't

The lungs never inflate in the womb.
They are at rest & compact like a dry sponge before it absorbs water. At birth the baby gasps forcefully, filling the lungs with air & it begins doing the work of gaining oxygen. The placenta, which did the work before can be clamped.

In brief: They don't

The lungs never inflate in the womb.
They are at rest & compact like a dry sponge before it absorbs water. At birth the baby gasps forcefully, filling the lungs with air & it begins doing the work of gaining oxygen. The placenta, which did the work before can be clamped.
Dr. James Ferguson
Dr. James Ferguson
Thank
Dr. Stephen Siegel
Internal Medicine - Pulmonology

In brief: Placenta supplies O2

The lungs don't breath when the baby is in the womb.
Oxygen is supplied to the baby through diffusion from the oxygen in the mother's blood to the fetal blood across the placenta. The oxygen then circulates in the fetal circulations. Carbon dioxide diffuses from the fetal circulation back to the mother's blood and the carbon dioxide is then exhaled via the mother's lungs.

In brief: Placenta supplies O2

The lungs don't breath when the baby is in the womb.
Oxygen is supplied to the baby through diffusion from the oxygen in the mother's blood to the fetal blood across the placenta. The oxygen then circulates in the fetal circulations. Carbon dioxide diffuses from the fetal circulation back to the mother's blood and the carbon dioxide is then exhaled via the mother's lungs.
Dr. Stephen Siegel
Dr. Stephen Siegel
Thank
Get help from a real doctor now
Dr. Jane Van Dis
Board Certified, Obstetrics & Gynecology
14 years in practice
47M people helped
Continue
108,000 doctors available
Read more answers from doctors