When does a heartbeat start in pregnancy?

When Does a Baby’s Heart Begin to Beat?

One of the most profound moments in early pregnancy is hearing—or seeing—your baby’s heartbeat for the first time. Around 5 to 6 weeks of gestation, the cardiac tissue in the developing embryo begins to generate rhythmic electrical activity. This tiny pulse can be detected on an ultrasound, often appearing as a flicker within the fetal pole, the first visible sign of the embryo.

It’s important to note that while this rhythmic pulsing is referred to as a "heartbeat," the heart as we know it hasn’t fully formed yet. At this stage, the embryo is still just a collection of developing structures. The pulsing comes from primitive cardiac cells beginning to contract, laying the foundation for the actual heart that will continue to develop over the coming weeks.

Many expectant parents find comfort in seeing this early sign of life. However, because timing can vary, not every ultrasound at 5 weeks will pick up the activity. Some might not see the fetal pole or detect motion until closer to 6 or even 7 weeks, especially if conception occurred later in the cycle.

The development of a detectable heartbeat is a key milestone, often associated with a significant drop in the risk of miscarriage. Though it’s easy to anthropomorphize this tiny flicker as a fully functioning heart, it’s really the very first step in a complex process of cardiac development that continues well into the second trimester.

Still, there’s no denying the emotional weight of seeing that first pulse. For many, it marks the moment when pregnancy begins to feel real—when a cluster of cells starts to seem like a tiny, growing life.