Wednesday, September 28, 2022

THE FETUS AS A PERSON--Why the fetal heartbeat at 6 weeks is a misguided construct


The fetus as a person: the political hot potato

Powered by the momentum of the Dobbs decision and the Roe v. Wade reversal, anti-choice activists have been moving forward in the direction they have wanted for decades. In a move to criminalize abortion and hold an abortion-performing provider liable for felony charges, the pro-life movement wants to give the fetus equal protection as a person under the 14th Amendment. The possible prosecution of an abortion doctor has already become reality. Not long after the ruling, the attorney general of Indiana vowed to investigate the physician who carried out the termination procedure on a ten-year-old-girl victim of rape.

The so-called fetal heartbeat
At the center of much of the discussion around abortion is the presence or absence of a fetal heartbeat at approximately six weeks, hence the drafting of “six-week abortion bans.” The heart, which supplies itself and all the other organs with blood, is essential to life, and in many cultures, the heart is the physical representation of emotions such as love and hate.

The heart’s elevated status in our minds gives the fetal heartbeat special significance, but while some people might picture a heart-shaped organ beating inside the six-week-old fetus, this is not the case. At that early stage, the nascent heart is only a specialized cluster of cells with the unique ability to emit regular electrical impulses like a pacemaker. These fluttery impulses are what an ultrasound detects as “beats,” but, in fact, the embryonic heart is not physically beating in the conventional sense. These unique, embryonic cells, which can perform the same fluttering function either inside or outside the fetus, still have another four to six weeks to develop into a working, four-chambered heart. If you’ve never seen the ultrasound (sonogram) 6-week fetal heart, here is fine example from Missouri Fertility:

The fetal brain v the fetal heartbeat
But the fetal organ that should arouse just as much passion as the heart is the brain, which will eventually control thought, emotion, memory, touch, motor skills, vision, and a myriad of other functions. The only organ that can’t be transplanted (so far), the human brain is largely responsible for our personalities, and has much more to do with the fetus as a person than the heart does. An examination of the stages of fetal brain development is more instructive and more useful in the fetal person debate.

Just as the heart begins as a specialized group of cells, the embryonic brain is only a neural plate by the fourth pregnancy week. In the sixth to seventh weeks, the neural plate folds to form the neural tube, which is the earliest nervous system tissue. The head portion becomes the rudimentary brain, which subdivides into the fore, mid, and hindbrain. At that point, new nerve cells are being produced at a rapid rate.

Diagram of development of neural tube
Neural Tube Formation (Adapted Shutterstock)

As early as the 9th week of gestation, the fetus is able to move the head, trunk, and extremities spontaneously. But from this period up to birth, the forebrain is relatively underdeveloped, and in utero fetal movements are largely due to reflexive activity in the part of the hindbrain called the brainstem. Such fetal movements can occur even in the absence of forebrain-initiated cognition such as reasoning or understanding. The “smiling” we sometimes see in a neonate is more of a brainstem-mediated phenomenon than a reflection of true emotion, given that anencephalic neonates without a forebrain can also display such behaviors. By the 36th to 38th week of gestation, the fetal brainstem will respond to external sounds like the mother’s voice, thus triggering reflexive body movements.

Diagram of fetal to adult brain development
Human brain development inside and outside the mother (From EHP

The importance of the forebrain can’t be emphasized enough. This is the headquarters of emotions such as anger, pleasure, fear, joyfulness, and the desire for social interaction—the phenomena that make us human. The forebrain doesn’t begin to functionally mature until near term. Before, at, or after birth, injury to the frontal lobes may have profound effects on cognitive function.

As we obsess with the mostly illusory phenomenon of the “fetal heartbeat” at six weeks, we blithely ignore the astonishing intricacies of the developing fetal brain, which will have much more to do with the fetus as a person than does the heart. At what point in its development does the fetal brain most endow us with characteristics that define us as persons? That’s open to discussion, but it is certainly farther along than the sixth week of gestation. The six-week-old fetal heartbeat is more of a political highpoint than it is a medical or embryological one. In the debate over the fetus as a person, we should shift our attention to the most phenomenal and consequential organ of the human body—the brain.


  1. Great article, Kwei. Thanks very much for laying this out for us laypersons. I always believed this to be the case, but I didn't have any knowledge to back my beliefs - a very unsatisfactory state of affairs that nevertheless seems to worry people less and less as time passes.

  2. Very good, Kwei. For the anti-abortion folks, I'd like for them to point to the soul, and tell me where and how it interfaces with the brain and body. Oh, that's the "miracle of life" that you just have to take on faith, and God has slung the soul down into that fertilized cell first thing. God must be terribly bored watching all these people have sex and waiting for those sperm to swim upstream...

    1. Sadly the “soul” is a most unromantic collection of hormones, enzymes, neurons, synapses, and electric currents.

  3. I think the soul is the most romantic of concepts. It can be thought of as the name we give to that unique combination of all those accidents that form essence of an individual being. That collection of qualities that make a person interesting, valuable, attractive, fun, irresistibile, lovable…..

  4. Consider this:
    A number of religions throughout history have believed the fetus becomes a person at birth when the soul enters the body in the first breath. (Likewise the soul leaves the body with one’s last breath.)