How does fetal circulation differ from circulation after birth?

How does fetal circulation differ from circulation after birth?

In fetal circulation, the right side of the heart has higher pressures than the left side of the heart. This pressure difference allows the shunts to remain open. In postnatal circulation, when the baby takes its first breath, pulmonary resistance decreases and blood flow through the placenta ceases.

Do umbilical veins carry blood toward or away from the fetus?

The umbilical arteries carry deoxygenated fetal blood toward the placenta for replenishment, and the umbilical vein carries newly oxygenated and nutrient-rich blood back to the fetus.

Why is pulmonary circulation reduced in the human fetus?

As the lungs expand, the alveoli in the lungs are cleared of fluid. An increase in the baby’s blood pressure and a major reduction in the pulmonary pressures reduce the need for the ductus arteriosus to shunt blood. These changes help the shunt close.

What happens to the circulatory system at birth?

The umbilical cord is clamped and the baby no longer receives oxygen and nutrients from the mother. With the first breaths of air, the lungs start to expand, and the ductus arteriosus and the foramen ovale both close. The baby’s circulation and blood flow through the heart now function like an adult’s.

How do babies breathe after water breaks?

The seal between the baby and the outside breaks when the mother’s water breaks. The baby may get exposure to oxygen during the birth process. But as long as the baby is still connected to its mother through the placenta via the umbilical cord, it’s not essential that the baby try to breathe yet.

When does blood enter the pulmonary blood vessels?

It’s only at the moment of birth when a baby takes its first breath that blood enters the pulmonary blood vessels to enter the lungs. 2  It is the exposure to oxygen that closes the shunts that bypass the pulmonary vein and other vessels—this relaxes these vessels so that blood can enter.

How are pulmonary veins connected to the heart?

In this condition, the 4 blood vessels (pulmonary veins) that carry oxygen-rich (red) blood to the heart from the lungs aren’t connected correctly. Normally these blood vessels should be connected to left upper chamber (atrium) of the heart.

How are pulmonary veins affected by congenital conditions?

Congenital conditions affecting the pulmonary veins can affect the number of these veins, their diameter, their development, or their connections and drainage (where they deliver the blood that is brought from the lungs). These vessels may also be affected by conditions in the region of the heart where they empty. 8 

How many babies are born with pulmonary venous return?

In a 2019 study using data from birth defects tracking systems across the United States, researchers estimated that each year about 504 babies in the United States are born with Total Anomalous Pulmonary Venous Return.

In this condition, the 4 blood vessels (pulmonary veins) that carry oxygen-rich (red) blood to the heart from the lungs aren’t connected correctly. Normally these blood vessels should be connected to left upper chamber (atrium) of the heart.

In a 2019 study using data from birth defects tracking systems across the United States, researchers estimated that each year about 504 babies in the United States are born with Total Anomalous Pulmonary Venous Return.

Congenital conditions affecting the pulmonary veins can affect the number of these veins, their diameter, their development, or their connections and drainage (where they deliver the blood that is brought from the lungs). These vessels may also be affected by conditions in the region of the heart where they empty. 8 

It’s only at the moment of birth when a baby takes its first breath that blood enters the pulmonary blood vessels to enter the lungs. 2  It is the exposure to oxygen that closes the shunts that bypass the pulmonary vein and other vessels—this relaxes these vessels so that blood can enter.