A dramatic ruling by the U.S. Supreme Court abolished the constitutional right to terminate a pregnancy. Following the ruling, laws banning abortions, supposedly based on the most advanced scientific and medical knowledge on fetal development, came into effect in several U.S. states. What does science really know about fetal development and abortions?

Last Friday (June 24 2022) the U.S. Supreme Court overturned the landmark Roe v. Wade ruling, reversing thus the 1973 ruling that a woman’s choice to undergo an induced abortion is a constitutional right. Following the justices’ decision, starting from the sixth week of pregnancy and in some cases even from the moment of conception, abortions became illegal in at least nine U.S. states. The immediate consequence of this dramatic ruling is the forced cancellation of planned and scheduled abortions. In the coming weeks additional U.S. states are expected to limit the rights of women* to terminate a pregnancy.

The 1973 Roe v. Wade ruling stated that a ban on abortions is unconstitutional, infringing on a pregnant woman’s right to privacy as well as on her right to choose for herself whether or not to undergo an abortion. Nearly immediately from the moment of the ruling, conservative activists started working on finding a way to overturn it. Already in 1985, Samuel Alito, a Catholic conservative, and today a Supreme Court Justice, suggested a strategy for the slow erosion of Roe v. Wade, up to the point of reversal of the ruling. This week, with the help of the three conservative justices appointed by former U.S. President Donald Trump, they succeeded.

Some states already had pre-existing so-called 'trigger laws', aimed at banning abortions, which were not valid due to the Roe v. Wade ruling. However, the overturning of the ruling activated these immediately. Some of these laws, such as the ones present in Alabama and Missouri, ban pregnancy termination from the moment of conception. Others – such as in the case of Ohio, Georgia and South Carolina – allow women the choice of abortion as long as 'heartbeats' are not detectable in the fetus. This implies that, with the excepton of cases of incest or rape, these laws prohibit abortion from about the sixth week of pregnancy (counted as the sixth week from the first day of the last menstrual cycle). 
At first glance, these laws seem less limiting than those in Alabama and Missouri, but since most women are not even aware of being pregnant during the sixth week, the 'heartbeat law' represents a de facto ban on abortions.

צבר תאים פועם שגודל במעבדה | Thomas Quail, Alvin Shrier, and Leon Glass / McGill University
During the sixth week of pregnancy it is possible to detect a pulse in the fetus, although it does not yet really have a heart. A cluster of pulsating cells grown in the lab | Thomas Quail, Alvin Shrier, and Leon Glass / McGill University 

Finger On The Pulse

The legislators of the 'heartbeat law', and even those of the draconian laws enacted in Alabama, Missouri and in other states, claim that these laws are based on the most advanced medical science and on the forefront of human rights. They claim that science has determined that 'unborn children'' are human beings in every aspect, and that these laws only protect their rights. In addition to these pseudo-scientific claims, the laws include different attempts of appeal to emotions: from the use of the words 'children' and 'heartbeats' to allude to a living human heart, to (in the case of Alabama) comparison of these laws to the U.S. Constitutional  Amendments that abolished slavery and granted women the right to vote, as well as to the comparison of abortions to mass murders such as the ones that took place during the Holocaust or in the Soviet Gulags.

What does the fetus and its heart really look like during the sixth week of pregnancy? The age of the fetus is calculated from the moment of conception (or more precisely from the day of ovulation), which occurs about two weeks after the first day of the last menstrual cycle, and therefore at this stage the fetus would only be four weeks old. At this stage the fetus looks like a tiny tadpole, attached to a yolk sac, about 4 millimeters in size. It does not yet have a brain, it does not resemble a human being, and it lacks the vital systems and organs that could allow it to be defined as a 'child', but a pulse can indeed sometimes be detected, even though it does not yet originate from a real heart at this developmental stage. 

When the fetus is three weeks old, during the fifth week of pregnancy, the organ that will eventually become the fetal heart resembles an enlarged vessel, a cluster of cells that contract, enabling the flow of liquid through the fetus. During the sixth week of pregnancy this vessel folds and begins to divide into compartments and sometimes the contractions can be detected by an ultrasound scan. The heart continues to develop quickly and by the ninth week of pregnancy it is already divided into four compartments and beats well. Detection of a normal pulse is a sign of a normal pregnancy and is associated with a decrease in the risk of miscarriage. However, natural miscarriages during the first weeks of pregnancy are not uncommon and by the seventh to eighth week it is not always possible to distinguish between a natural miscarriage and a heavy menstrual bleeding. 

At this developmental stage a fetus has no independent existence outside of the uterus, and if aborted, either naturally or by induction, it does not continue to develop. Fetuses born during the 20th week of pregnancy or beforehand have no chance of survival. Survival rates remain close to zero between weeks 21 to 23. At 24 weeks of pregnancy, the survival rates of a prematurely born fetus are between 40-70 percent, especially if the preterm fetus weighs 500 grams or more and if the prenatal and neonatal intensive care unit is well-equipped and has a skilled staff. The stage of pregnancy from week 24 onwards is termed the age of fetal viability, since a premature fetus born during this stage has a reasonable chance of survival. 

In 1992, in the ruling of Planned Parenthood v. Casey, the U.S. Supreme Court re-affirmed Roe v. Wade and was even more lenient, ruling in favor of the right for an abortion until the stage of fetal viability. States could impose a ban on abortions after the age of fetal viability, in order to protect the fetus’s potential life, as long as the mother’s life and health were not in danger. For this reason, laws aimed at banning abortion before the stage of fetal viability, such as during the sixth week of pregnancy, were eventually dismissed in the courts. Quite a few states found other ways of making it as difficult as possible for women to get an abortion, without officially banning it – such as using different means of shutting down clinics in which pregnancy terminations were carried out. 

Now, this ruling has been overturned as well, along with Roe v. Wade, and states are free to ban abortions at any stage. The wording of these abortion banning laws and the publications related to them, mention heartbeats and other signs of life in an attempt to make people consider the tiny tadpole, which lacks an independent existence, as a whole living  being, and possibly to cause confusion between the stage of presence of a heartbeat and the moment at which the fetus reaches the age of viability. 

עובר בן פחות מעשרה שבועות | lunar caustic, flickr

Pain receptors begin to appear on the skin only from the tenth week of pregnancy. A fetus less than ten weeks old | lunar caustic, Flickr


Suffering is An Ineradicable Part of Life

Part of the appeal to emotions in the anti-abortion laws sometimes includes claims that the ban on abortions is designed to prevent pain inflicted on the fetus. In light of this claim, states such as Nebraskaban abortions from the 22 week of pregnancy, at least for the time being. In North Carolina the same argument was used in an attempt to ban abortions from week 20 of pregnancy, but abortions are now banned there only from the age of viability. The pain argument is mentioned even in laws banning abortions from the sixth week of pregnancy, although it is not used to justify the ban. According to legislators, science has determined that by week 20 of pregnancy a fetus can sense pain, despite the fact that the scientific consensus is that it cannot feel pain before week 26.

In order to feel pain, a fetus has to undergo a few developmental stages: pain requires the presence of pain receptors, a neural connection between these sensory receptors to the spinal cord and brain, and appropriate structures in the brain able to identify pain and generate a pain sensation. According to an extensive review by the Royal College of Obstetricians and Gynaecologists (RCOG), pain receptors begin to appear on the skin only from the tenth week of pregnancy, and in the internal organs only starting from the 13th week of pregnancy. These continue to develop and mature during the next six to eight weeks. However, at this stage they are unable to communicate the received signals to the brain. Only from the 18th week of pregnancy do the pain receptors connect to the spinal cord. At this stage, the fetus already reacts to touch – if its hand is accidentally pricked, or even touched, for example during amniocentesis, a withdrawal reflex will be activated and the hand will be quickly pulled back away from the needle. This movement is involuntary since it is mediated by the spinal cord and does not involve the brain, similarly to the knee-jerk reflex that generates a sudden kicking movement of the lower leg in response to a sharp tap of the patellar tendon, found beneath the kneecap. The withdrawal reflex is not necessarily pain-related and it also occurs in babies following a light touch, implying that its existence does not indicate the existence of a pain sensation. For the occurrence of a pain sensation, the appropriate “equipment” is required to be present in the brain.

The required brain structures are the cortex, located on the surface of the cerebrum, and three main regions within it: the insula, a region of the cerebral cortex related to emotions and sensation; the primary somatosensory cortex, responsible for the processing of somatic sensations such as touch and pain, and more; and the anterior cingulate cortex (ACC), responsible for the processing of stimuli. In addition, these regions require the presence of working and functional neural connections to other parts of the brain. These connections begin to appear and to function starting from the 24th week of pregnancy and continue to develop in the weeks that follow. It is not at all certain that a fetus can sense pain before these connections complete their development (around week 29), but there is certainly no reason to think it can sense pain before week 24, when the minimal systems required for pain sensation have not yet developed in the brain

אילוסטרציה של אישה עם בדיקת היריון | Lopolo, Shutterstock
Grief and regret? After the abortion an overwhelming majority of women do not regret it. Illustration of a woman with a pregnancy test | Lopolo, Shutterstock

Grief and Regret?

While most abortion banning laws do not mention this, many anti-abortion proponents claim that an induced abortion also poses a threat to the mother’s mental health. They claim that most women will regret having undergone an abortion and that they are at an increased risk of developing depression. However, this claim is not supported by evidence. 

One study that followed the rate of regret among about 670 women who chose to undergo an abortion, across thirty abortion clinics in the U.S., found that 95 percent of women did not regret their decision even three years later, despite the fact that 53 percent of the women defined the decision to abort as a difficult one. In addition, the intensity of women’s emotions concerning the abortion subsided over time. According to the study, the stigma and the negative campaigns driven by various anti-abortion organizations caused stress to women who were undecided on whether or not to undergo an abortion. However, eventually, the vast majority of women do not regret having undergone an abortion and are at peace with their decision.

In a previous study by the same research group, which included 960 women, including the aforementioned 670 women, the researchers followed women for five years folowing their abortion, as well as women who sought an abortion but were denied the request and were forced to carry the baby to term. Women who were denied an abortion reported more symptoms of anxiety and lower self-esteem one week after seeking treatment at a clinic, compared to the other women. However, over time these feelings improved and after a few years no differences in the psychological well-being were found between the women who have given birth and those who had undergone an abortion. In addition, no differences in the level of depression were found between the two groups and no evidence indicated that undergoing an abortion or not undergoing an abortion was mentally detrimental for the women. 

In contrast, additional studies carried out by this research group found that women who were denied an abortion were at a greater risk of living in poverty, with no money for basic commodities such as food or fuel. Their credit rating was lower and they were at a greater risk of being unemployed, bankrupt, or evicted from their home. This, despite the fact that both groups – women who terminated their pregnancies and women who were forced to carry them to term – started from a more or less similar socioeconomic situation. In addition, the risk of childbirth is generally much greater than the risk of terminating a pregnancy. Indeed, two out of the women who participated in the study and were denied an abortion died during childbirth, while none died as a result of a legal abortion. 

A similar study carried out in Finland by a different research group, has reached similar conclusions. In the study, the researchers analyzed data from over one thousand women under the age of 18 who became pregnant and either had an abortion or have given birth, and found no difference in the mental health of the women in the long term. In contrast, the study found that women who had undergone an abortion were more likely to have a higher level of education and to be better-off financially by the age of 25, compared to those who have given birth. The results of this study do not necessarily indicate that an abortion improves women’s education and salary, but it is possible that the chances of these women improved due to the fact that they did not need to support a child.

An abortion is an unpleasant experience and usually not an easy decision to undertake, but women who choose to terminate their pregnancies are not at an increased risk of suffering from grief, regret or mental problems. Campaigns and claims by anti-abortion proponents make the decision to abort even more difficult and stressful than it already is in the first place. The argument that a fetus already has a heart by week six of pregnancy is more or less true, and by week nine it is correct, but this is not related to the ability of the fetus to exist independently, which is determined by the age of fetal viability. In addition, according to the scientific evidence, a fetus is unable to sense pain before the 24th week of pregnancy, while all abortions are in fact carried out long before this, with the exception of pregnancy terminations that are carried out for medical reasons - due to life-threatening conditions for the mother or medical problems in the fetus.


* The words ‘woman’ or ‘women’ also refer to any person who may become pregnant.

This article is based on a publication that first appeared in the blog “Noam’s Ark – Biological Thoughts”. The publication is courtesy of Noam Levitan and all rights are reserved to him.