Researchers today pinpoint 22 days as the earliest parents-to-be can detect a heartbeat. Because fetuses receive oxygen through their blood, rather than their lungs, their circulatory systems are built differently while they’re in the womb. Blood circulates via a system of shunts, rather than the full-fledged circulatory system you’d recognize in a fully-grown human.
There are two important features of the fetal heart to be aware of:
The foramen ovale, an open flap between both chambers of the heart which shuts after your baby is born
The ductus arteriosus, a major blood vessel which, after birth, will be replaced by the aorta and pulmonary artery to connect with your newborn’s lungs
What does this mean for moms-to-be? It means that at 22 days, your baby’s heart is still just a cluster of cells.
So, while you may be able to sonically hear your little one’s heartbeat with a fetal heart rate monitor, it’s essential to keep seeing your doctor to confirm your baby is developing at a healthy rate.