Lawmakers in 15 states have introduced so-called fetal heartbeat legislation this year to ban abortion as soon as a doctor can detect cardiac activity in an embryo , which typically happens at around six weeks into a pregnancy.

But doctors say that not only is that cutoff completely arbitrary, its also based on the false premise that a fetal heartbeat a phrase often included in the bills titles even exists at that stage of pregnancy.

To say that a six-week pregnancy has a fetal anything is incorrect, explained Dr. Colleen McNicholas, an obstetrician-gynecologist who performs abortions, noting that the term fetal heartbeat isnt even applicable until about 10 weeks into a pregnancy. At that point, an embryo has developed sufficiently to be called a fetus.

At six weeks, an embryos cardiac development doesnt at all resemble what would eventually become a functioning human adult heart, she said. At that point, it really is just these two tubes with a couple of layers of cardiac or heart cells that can vibrate or cause some sort of movement that we use colloquially to talk about a fetal heartbeat.

McNicholas is based in Saint Louis, Missouri, where Gov. Mike Parson (R) is expected to sign a bill banning abortion at that stage in the coming weeks.

Governors in Kentucky, Mississippi, Ohio and Georgia have also signed similar legislation this year, though the bans already face legal challenges.

Dr. Carley Zeal, another OB-GYN based in St. Louis, expressed similar frustration with the fetal heartbeat terminology these bills are using.

An embryo at six weeks has no other functioning organs, no ability to live on its own, and its actually so small that when we review pathology from an abortion or a miscarriage at six weeks gestation, theres not an identifiable fetus to review, she said. Its just a gestational sac and some cells, so its very small and definitely not able to live outside of the womb.

At that point, an embryo is less than a centimeter long, she said. Thats smaller than a penny or the width of most peoples pinky fingers.

But the way the lawmakers orchestrating these abortion bans speak about pregnancy at that stage leaves a very different impression.

If there is a detection of a heartbeat, that child is a living human being, and you can no longer murder this child in its mothers womb, Kentucky state Sen. Matt Castlen (R) said at a press conference when introducing his states fetal heartbeat bill in January.

What were doing is ... recognizing that the child with a beating heart inside of mom thats got a heartbeat, that theyre preparing a nursery for, that is wiggling around inside mom, is actually a person, Georgia state Rep. Ed Setzler (R), the architect behind his states abortion ban, said in a March interview.

Science tells us that the heartbeat really is the beginning of life and the end of life, he continued.