Fetal Circulation and Physiological Changes at Birth

Role of the Placenta in Fetal Circulation

The placenta is a vital organ in fetal development, acting as the interface between the maternal and fetal circulatory systems. It provides oxygen and nutrients to the developing fetus while removing waste products.

Components of Fetal Circulation

• Placenta: Facilitates gas exchange and nutrient delivery.
• Umbilical Vein: Transports oxygen-rich blood to the fetus.
• Ductus Venosus: Directs blood to the inferior vena cava, bypassing the liver.
• Foramen Ovale: Allows blood flow between atria for oxygen distribution.
• Ductus Arteriosus: Connects pulmonary artery to aorta, bypassing the lungs.

Physiological Changes at Birth

At birth, significant circulatory changes occur as the newborn adapts to independent respiration:

• The foramen ovale closes, ensuring separate pulmonary and systemic circulation.
• The ductus arteriosus constricts, directing blood to the lungs.
• The placenta is removed, triggering increased systemic vascular resistance.

Importance of the Placenta in Development

The placenta ensures fetal well-being by regulating hormonal signals, immune protection, and metabolic functions.