When Does a Fetus Have a Heartbeat? – Aunty Jane

The term "fetal heartbeat" is often used to describe early pregnancy development, but it’s important to understand what is actually happening at a biological level.

At around five to six weeks gestation, an ultrasound may detect electrical activity in a cluster of specialised cells known as the cardiac crescent. These cells begin to emit rhythmic electrical impulses, which can appear as a flicker on the screen. However, at this stage, there is no fully formed heart — no chambers, no valves, and no cardiovascular system as we understand it in later stages of development.

The early electrical activity comes from cells that, if the pregnancy continues, will eventually organize and differentiate into the complex structures of the heart. This process unfolds over several weeks, with a more recognisable four-chambered heart structure not forming until after eight weeks gestation.

The language around "heartbeat" can create confusion and emotional impact, particularly in legal and political conversations. From a medical perspective, what is being observed early on is cardiac activity — the first step in the heart’s development, not a functional heart itself.

At Aunty Jane, we believe it’s essential that people receive clear, evidence-based information about their bodies. Understanding what is happening — and when — allows individuals to make informed, empowered decisions about their healthcare.

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