Texas' new draconian abortion ban is based on when a fetal heartbeat forms - at six weeks.
However, a heartbeat isn't present at 6 weeks, doctors say.
A six-week-old fetus doesn't have a cardiovascular system, the sound of the thumping is from the machine.
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Newly passed laws in Texas mean that people cannot have an abortion after six weeks - the point where a "fetal heartbeat" appears, and the point before most people know they're pregnant.
However, doctors are coming forward to say that the "fetal heartbeat" isn't a real medical point in fetal development, casting doubt on the credibility of the Fetal Heartbeat Bill.
Heartbeats in humans produce thump-thump sounds caused by the opening and closing of the heart's valves.
However, in conversation with NPR, Dr. Nisha Verma, an OB-GYN who specializes in abortion care and works at the American College of Obstetricians and Gynecologists, says that that heartbeat doesn't exist in 6-week old fetuses.
"At six weeks of gestation, those valves don't exist," she told the news site.
"The flickering that we're seeing on the ultrasound that early in the development of the pregnancy is actually electrical activity, and the sound that you 'hear' is actually manufactured by the ultrasound machine." Dr. Verma added.
Dr. Jennifer Kerns, an OB-GYN and associate professor at the University of California, San Francisco, also told NPR that this noise is simply not a sign of a working heart or functional cardiovascular system.
Dr. Kerns also added that this is a term doctors would use to simplify complicated medical discussions with patients - similar to the term tummy ache, rather than gastroenteritis, or dizzy spell instead of vertigo - and should not be used to make laws.
Likewise, at six weeks post-conception, the correct term is an embryo.
But "fetus" may have an appeal that the word "embryo" does not, Kern told NPR: "The term 'fetus' certainly evokes images of a well-formed baby, so it's advantageous to use that term instead of 'embryo' - which may not be as easy for the public to feel strongly about, since embryos don't look like a baby," she explains. "So those terms are very purposefully used [in these laws] - and are also misleading."
A number of laws have been crafted to limit access to abortion based upon this false notion of a fetal heartbeat, according to the Guttmacher Institute - but the Texas law is the first to go into effect.
Now, anyone who needs or wants an abortion in Texas will have to drive over 200 miles to get one legally.
Data has shown that abortion bans - as Texas' new law essentially is - do not stop abortions, just safe, legal ones - Amnesty International state.
In fact, a study by the Guttmacher Institute found that abortion rates are higher in countries that ban abortions.