How does a fetus breathe?

Thoracic movements.: Here are two answers to your tricky question: 1) fetuses do not literally breathe; they have increasingly frequent thoracic movements near term to prepare for extrauterine life without actually exchanging gases through their lungs. 2) gas exchange in utero is via the placenta (not the lungs); the fetuses obtain the required oxygen through placental function and complex hemoglobin interactions.

The fetus does: Breathe, in fact breathing movements are part of the biophysical profile to determine the health of your baby. But respiration, the transfer of oxygen and carbon dioxide occurs at the placenta.