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

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
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