Understanding Patent Ductus Arteriosus and Patent Foramen Ovale in Newborns

When a baby is born, the circulatory system undergoes significant changes as the lungs begin to function. One of these changes includes an increase in blood flow to the lungs, which leads to more blood returning to the left atrium of the heart. As a result, the pressure in the left atrium becomes higher than that in the right atrium. This pressure difference causes the foramen ovale — a small flap-like opening between the two atria that is present during fetal development — to close functionally.

What Happens to the Foramen Ovale After Birth?

Although the foramen ovale typically closes shortly after birth due to pressure changes in the heart, the actual anatomical closure may take up to a year. Interestingly, studies suggest that approximately 25% of adults still have an open foramen ovale anatomically, but this condition usually does not cause any hemodynamic issues and often goes unnoticed throughout life.

Understanding the Ductus Arteriosus

During fetal development, the ductus arteriosus is a vital blood vessel that connects the pulmonary artery to the aorta, allowing blood to bypass the lungs. After birth, when the baby starts breathing and the lungs become functional, this vessel is no longer needed. Normally, the ductus arteriosus closes within the first few weeks of life — usually between 6 to 8 weeks — and turns into a fibrous band called the ligamentum arteriosum.

Patent Ductus Arteriosus: When the Ductus Doesn't Close

If the ductus arteriosus remains open beyond the first year of life, the condition is referred to as patent ductus arteriosus (PDA). While most individuals experience complete closure by the age of one, those who don't may require medical intervention depending on the size of the opening and the presence of symptoms such as heart murmurs, fatigue, or difficulty breathing.

In summary, both the foramen ovale and the ductus arteriosus play essential roles during fetal development and typically close shortly after birth. While a persistently open foramen ovale is relatively common and usually harmless, a patent ductus arteriosus may require closer monitoring and, in some cases, treatment to prevent complications related to abnormal blood flow.