What common transition occurs in a newborn's circulatory system after birth?

In the transition from fetal to postnatal life, several important changes occur in a newborn's circulatory system as it adapts to breathing air and functioning independently outside the womb.

The closure of the umbilical artery occurs as the blood flow from the placenta stops; this vessel is no longer needed since the baby is no longer reliant on maternal circulation. The umbilical arteries constrict and eventually close, becoming the medial umbilical ligaments.

The closure of the foramen ovale is crucial as this shunt, which allows blood to pass directly from the right atrium to the left atrium during fetal life (bypassing the lungs), must close to prevent mixing of oxygenated and deoxygenated blood. Typically, this closure happens functionally at birth when the pressure in the left atrium becomes higher than in the right due to the initiation of breathing and the resulting changes in pulmonary circulation.

Closure of the ductus venosus also plays a significant role. In utero, this vessel allows oxygen-rich blood from the placenta to bypass the liver. After birth, the cessation of umbilical cord blood flow leads to its closure, resulting in the flow of blood through the liver.

Since all these transitions—closure of