When do most babies 'foramen ovale close?

Most babies 'foramen ovale closes within weeks to months of birth.

During fetal development, the foramen ovale is part of the structure of the heart that allows blood to bypass the lungs, allowing oxygenated blood to mix with unoxygenated blood. However, as the baby is born and begins to breathe independently, lung function gradually increases and the foramen ovale gradually closes. Normally, the foramen ovale closes naturally within a few weeks of birth, depending on the baby, but most babies close completely within three to six months of birth. However, sometimes the foramen ovale does not close completely, which may require further evaluation and management.