Why do conservatives think embryos have a heartbeat at 6 weeks?
“To wit: though pulsing cells can be detected in embryos as early as six weeks, this rhythm — detected by a doctor, via ultrasound — cannot be called a “heartbeat,” because embryos don’t have hearts. What is detectable at or around six weeks can more accurately be called “cardiac activity,” says Robyn Schickler, OB/GYN and fellow with Physicians for Reproductive Health. The difference between “cardiac activity” and “heartbeat” may seem linguistically minimal, but Schickler and others argue otherwise. At this stage, she says, what doctors can detect is essentially communication between a group of what will eventually become cardiac cells.
“From very early on, different cells are programmed to do different things for what is eventually a fully functioning human body,” says Jennifer Kerns, an OB/GYN and professor at the University of California in San Francisco. “These are cells that are programmed with electrical activity, which will eventually control the heart rate — they send a signal telling the heart to contract, once there is a heart.” It is this early activity which ultrasounds detect — not a heartbeat”