- A new Texas law that effectively bans abortion after 6 weeks has also been dubbed the “heartbeat bill.”
- At 6 weeks, an embryo does not have a fully formed heart. Rather, it has a cluster of cells (that eventually forms into a heart) that emits electrical signals, which can be detected on an ultrasound.
- The heartbeat “sound” on an ultrasound is actually generated by the ultrasound machine itself during this time period.
Texas recently passed Senate Bill 8, a law that prohibits abortion at 6 weeks of pregnancy.
Also dubbed the “the heartbeat bill,” the law — which went into effect Sept. 1 — bans abortion at the first detection of a fetal heartbeat, which occurs around 6 weeks of pregnancy.
But reproductive health specialists say that at 6 weeks, an embryo doesn’t have a fully formed heart, but rather a cluster of cells that emits electrical signals.
Those cells will eventually form into a heart around 8 weeks after the last menstrual cycle.
It isn’t until 16 to 18 weeks of gestation that the heart, valves, and vessels can be seen on an ultrasound.
According to Dr. Jennifer Kerns, an associate professor in the department of obstetrics, gynecology, and reproductive sciences at the University of California, San Francisco, the term “fetal heartbeat” doesn’t accurately represent what is detected at 6 weeks of pregnancy.
“The term ‘heartbeat’ is very misleading for a 6-week embryo. What is labeled a ‘heartbeat’ is actually the electrical activity that can be seen on ultrasound,” Kerns told Healthline.
Up until 8 weeks of gestation, the pregnancy is still in the embryo state. After 8 weeks, it’s called a fetus, explained Kerns.
Between 6 and 8 weeks, the cells of the embryo change into specific cells that support a specific body system, like the cardiovascular system or pulmonary system.
But at 6 weeks, an embryo does not have what we think of as a heart, said Kerns.
“A heart has four chambers with valves that allow blood to collect and then be pumped out to the body. At 6 weeks, there is a cluster of cells that have electrical activity,” Kerns said.
Kerns said the term “fetal heartbeat” is misleading for a 6-week embryo since the “heartbeat” is technically electrical activity that can be detected on an ultrasound.
“The sound that is produced from that electrical activity is generated from the ultrasound machine translating that electrical activity, not from the opening and closing of valves, as is true for a fully formed and functioning heart,” Kerns said.
Dr. Nancy L. Stanwood, the section chief of family planning at Yale Medicine and associate professor of obstetrics, gynecology, and reproductive sciences at Yale School of Medicine, said it’s important to first clarify the timing of pregnancy.
Obstetricians and gynecologists start counting from the last menstrual period.
“This means that for the first 2 weeks, the person isn’t even pregnant yet,” Stanwood said.
In people with regular menstrual cycles, ovulation occurs 2 weeks after their period. Conception happens in the fallopian tube around this time.
At about 3 weeks, the fertilized egg travels from the fallopian tube to the uterus, where the egg implants to the lining of the uterus, explained Stanwood.
It then takes about a week for the pregnancy hormone to be detected in a urine pregnancy test.
An embryo becomes a fetus 9 weeks after the last menstrual cycle, which is when the main structures of the heart are formed, said Stanwood.
The four chambers of the heart, the valves, and the vessels can be seen in the second trimester, around 16 to 18 weeks, according to Kerns.
Ultrasounds are usually conducted at this point to identify any cardiovascular malfunctions.
Even at this point, the heart relies on other organ systems to be fully functioning, said Kerns.
At 6 weeks, an embryo does not have a fully formed heart. Rather, it has a cluster of cells (that eventually forms into a heart) that emits electrical signals, which can be detected on an ultrasound.
Reproductive health specialists say the term “fetal heartbeat” is misleading.
It isn’t until 16 to 18 weeks of pregnancy that the heart, valves, and vessels can be seen clearly in an ultrasound.