Only later, after the 10th week or beyond, is a heartbeat audible with a Doppler fetal monitor. The heartbeat shows up around this time or shortly after as a flickering motion on an ultrasound. Beating occurs earlier, at the very end of the fifth week or at the start of the sixth week, when the heart is immature and lacks most of its identifiable features, including its iconic chambers. Precise answers to these questions depend on an individual’s definitions, but the heart doesn’t have all of its major components until the beginning of the 10th week of pregnancy. These sources don’t include many details on how heart development occurs, so it’s no surprise our reader was confused.

And plenty of medical textbooks use the words “heart” and “heartbeat” to refer to the embryo’s developing heart. Thus, ACOG does not use the term ‘heartbeat’ to describe these legislative bans on abortion because it is misleading language, out of step with the anatomical and clinical realities of that stage of pregnancy.”Īt the same time, many online medical websites, including the Mayo Clinic, do refer to the heart and its beating early-on in pregnancy. The American College of Obstetricians and Gynecologists also has said in a statement, “What is interpreted as a heartbeat in these bills is actually electrically-induced flickering of a portion of the fetal tissue that will become the heart as the embryo develops. A Popular Science article, for instance, described the heartbeat at six weeks as a “rhythm a doctor can pick up on an ultrasound,” stating that “it isn’t a heartbeat, because the embryo has no heart.” While none of the laws are currently in effect - and some have already been blocked in court - news coverage of the legislation has led to confusion. Before then, the correct term is an embryo. In medicine, however, a fetus doesn’t exist until eight weeks after fertilization, or at the end of the 10th week of pregnancy, when all the major organ systems have begun to form. “Fetal heartbeat” is more of a legal term than a medical one, as some of the state laws specifically define a fetus as existing from the moment of conception. All of the state laws allow abortion if the pregnant woman’s life or physical health is severely endangered, but only some make exceptions for fatal chromosomal anomalies in the fetus or in cases of rape or incest. Others, including proponents, call them “heartbeat” and sometimes “fetal heartbeat” legislation.

In the past four months, five states (Kentucky, Mississippi, Ohio, Georgia and Louisiana) have passed laws that ban abortion once a heartbeat becomes detectable during a pregnancy, which is generally possible by the sixth week of gestation, or the fourth week after conception.įor this reason, abortion rights advocates such as Planned Parenthood refer to these measures as six-week abortion bans. Thank you for any information that you can provide.

I was confused after reading a Popular Science article along with information shared by MayoClinic.

When do doctors actually hear a heartbeat? When does an ACTUAL heart become fully functioning and formed? Some forms of ultrasound can detect cardiac activity in an embryo in the sixth week, but a heartbeat wouldn’t be audible until about 10 weeks on a Doppler fetal monitor. Q: When is the human heart fully developed, and when are heartbeats audible during pregnancy?Ī: A developing heart has all of its primary structures after about nine weeks of pregnancy.

When does a fetus have a heartbeat