Fetal Development, Abortion, and Pro-Life vs Pro-Choice Stances.
- Olivia Fleischer

- Jul 7, 2022
- 11 min read
Updated: Mar 19, 2023
Before I jump in to the list of facts that I want to share surrounding the heated topic of abortion, I do want to make it clear that I personally do not reject any other woman's beliefs about life. Contrary to popular belief, to be pro-choice is not to be pro-abortion, but rather it is to be unbiased on the issue of personhood. It is not up to me to decide for other people when they believe personhood begins, and I do not intend to debate it. The only thing that pro-choice is bias about is whether or not one single belief on personhood should be forced onto all people.
The sole purpose of this post is therefore to provide the science and objective information behind fetal development and abortion, because I think it is hugely important to get language and facts straight in order to fully understand our own perspectives and the perspectives of those around us. My main goal here is to educate. And hopefully through the facts, all those invested in this debate can learn a bit more about their own views and the views of the other side.
Key Events in Pregnancy and Embryonic/Fetal Development:
Day 1 (or approximately 2 weeks after the start of a carrier’s last period): Fertilization
A sperm meets an egg in the Fallopian tube, and they combine to become one cell called a zygote. The DNA of this zygote is brand new, completely unique, and has all the blueprints necessary to potentially become a baby (but not all the nutrients to do so - those come solely from the carrier's body, and a zygote has no chance of survival without that).
Individuals who identify as pro-life believe this zygote is a person because of its unique genetic makeup, and are therefore against its termination from this point on.
Week 1-2 (or week 3-4 of gestation/after last period): Implantation
The zygote divides to form a ball of cells called a blastocyst. The blastocyst eventually implants or buries itself in the uterine wall and begins to get all of the nourishment necessary to survive and grow from the mother or carrier’s body.
If the blastocyst does not make it to the uterus and instead gets implanted in a different part of the carrier’s body (in the Fallopian tube, for example), then it is called an ectopic pregnancy. There is no chance of this blastocyst surviving long-term, but it can continue to grow for several weeks and can harm its host by damaging adjacent organs and/or by causing life-threatening blood loss. The blastocyst must be removed in a timely manner to prevent complications and possible death to the one carrying it.
Week 4 (or week 6 of gestation/after last period): Embryonic Phase
The blastocyst becomes an embryo as its organs begin to form.
Around day 22 or 23 after fertilization, an electrically-induced rhythm can sometimes be picked up on an ultrasound. I do want to clarify that this is not a heartbeat though, as an embryo does not yet have a fully-formed heart. This language is extremely important, as it is the reasoning behind “heartbeat bills” or 6-week abortion bans. The American College of Obstetricians and Gynecologists specifically avoids using the term “heartbeat” when describing these legislative bans on abortion because “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.” I can understand why those who are pro-life may argue that this distinction does not matter because this fetal tissue has the potential to become a fully-formed heart, but the objective fact of the matter is that anatomically and clinically, there is no actual heart organ at this point in development. Calling this tissue a heart at 4 weeks is misleading because it is scientifically incorrect.
I’d also like to point out that at this point in pregnancy, the pregnant person’s next expected period is only approximately 2 weeks late. Menstrual cycles can vary greatly, so it is extremely common for a person to not even know that they are pregnant at this point.
Week 7 (or week 9 of gestation)
Embryo is 0.6 to 0.7 inches long, or the size of a cherry.
According to the CDC, 77% of all abortions occur before the end of this stage of pregnancy.
Week 8 (or week 10 of gestation): Fetal Phase
The embryo becomes a fetus, and all major organs and bodily systems including the heart are present, although most are not yet fully functional. The heartbeat can now be audible on a Doppler fetal monitor, but this heartbeat does not yet mean that the fetus is viable.
Some people believe in defining personhood at this stage.
Week 11 (or week 13 of gestation)
First trimester screening for certain birth defects related to the heart and chromosomes (such as the chromosomal disorder that causes Down Syndrome) can be completed between 11 and 13 weeks of gestation. It is important to note that these tests cannot give the pregnant personal conclusive results on the health of their fetus any earlier than at this point in the pregnancy.
According to the CDC, 93% of all abortions are performed before the end of this stage of pregnancy. In other words, very nearly all abortions occur in the first trimester, long before fetal viability.
Week 14 (or week 16 of gestation): Start of Second Trimester
Week 18 (or week 20 of gestation)
Spontaneous/accidental loss of a fetus in the womb before this week of pregnancy is commonly called a miscarriage (or, in the medical field, a spontaneous abortion). The true rates of miscarriage are unknown because they can occur before a person even knows that they were pregnant. For those who are aware of their pregnancy, about 10-15% end in miscarriage. Most occur in the first trimester before week 12 of gestation, but some also occur up to week 20.
According to the CDC, only 1% of all abortions are performed after this stage of pregnancy, and there are so few performed after 23 weeks that data cannot be found on it. When those who are pro-life, the media, and politicians focus on “late-term abortion” (which is not actually a real scientific term), it is therefore a misrepresentation of the statistics. It also excludes the deeply tragic fact that most of these pregnancies are wanted by the carrier. Most people undergoing these abortions planned on carrying to term and planned on being parents - it is only for a devastating medical reason that they then choose to go through with the termination of their pregnancy this late in the process.
Week 22 (or week 24 of gestation)
Pain receptors are present throughout the fetus’s body, but a functional thalamocortical connection is needed in the brain for pain stimuli to actually be detected. These fibers do not begin appearing until 24 weeks of gestation and are fully formed at 30 weeks. Before this, pain cannot be felt by the fetus. Those who are pro-life may assert that a fetus can be seen pulling away from a pin prick or other pain stimuli in the womb at 20 weeks, but there is no scientific evidence that this reaction is due to feeling pain or having consciousness – it is at most just a reflex.
Consciousness also requires a sophisticated network of connections in the brain, which again includes the need for the thalamocortical complex that is only just beginning to form at this stage of gestation. A fetus at 24 weeks will therefore have very limited consciousness at most. It will not have complete thoughts, the ability to make and store memories, or full awareness of its environment, for example
In the US, this is also the approximate week that viability occurs, meaning the fetus may be of sufficient maturity to survive outside of the carrier’s womb if delivered prematurely. If delivered, this is when the fetus becomes a baby by definition and is considered a patient when presented to the physician who will take over its care. Before this week of gestation, survival outside of the carrier's womb is very unlikely. This makes viability another valid scientific belief for when life begins. After the stage of viability, the ethical question of whether or not the fetus has personhood starts to become more objective, as life independent of another human's body is now possible.
Week 26 (or week 28 of gestation): Start of Third Trimester
Weeks 37-41 of gestation: Full-Term Pregnancy
Before moving on to abortion statistics, I want to clarify one more bit of language when it comes to science and development. And that is the difference between an embryo, a fetus, an infant/baby, and a child. Although I defined most of those terms above, I have also added the below photos and definitions to make these distinctions as clear as possible. Again, I am not here to change anyone’s mind on when life begins and I am not trying to stir any emotional reactions – your belief on when personhood begins is yours alone to choose. I just want to make it clear that it is scientifically incorrect to say that abortion is the murder of a baby or a child. It is not. Abortion is the termination of an embryo or a fetus (that could potentially become a baby or a child). To use these terms interchangeably is incorrect.
Key Facts About Abortion:
There are many different definitions of abortion (see my next post for more information on why this is so problematic now that Roe has been overturned), but one definition is the termination of a pregnancy after, accompanied by, resulting in, or closely followed by the death of the embryo or fetus.
There are two main types of medically-induced abortions: the abortion pill (or two different medications that cause cramping and bleeding to empty the uterus), and in-clinic abortion (or the surgical removal of fetal tissue from the uterus).
1 in 4 women will get an abortion by the age of 45.
59% of abortions were obtained by women who already have children.
45% of people who receive abortion care were married or living with their partner. (Abortions are therefore not just for promiscuous women who do not want kids and do not want accountability).
Abortions are safe, with major complications occurring only 0.025% of the time.
Studies have shown that pregnancy and childbirth are associated with much higher risks to a women's health than abortion is. The US has one of the highest maternal mortality rates in the entire developed world, with black women dying at 3-4x the rate of white women.
There is no link between abortion and breast cancer. (Prior studies suggesting a link have been proven to be methodologically flawed).
There is also no link between safe abortion and the ability to get pregnant again in the future.
When it comes to mental health, research repeatedly shows that having an abortion is not associated with an increased risk of mental health problems such as depression.
A January 2020 study actually showed that the most commonly felt emotion at all times over a 5 year period after abortion was relief. (This is not to say that all people who choose abortions experience relief - some do experience regret. But most do not regret their decision later down the road).
Women who are denied an abortion are more likely to experience higher levels of anxiety, lower life satisfaction, and lower self-esteem compared with women who did receive a wanted abortion.
62% of those who have had abortions reported having a religious affiliation. (This is extremely important. Although abortion goes against the beliefs of many Christians and Jehovah's Witnesses, it is important to note that not all people of a specific religion share this stance, and that abortion is not as big of a deal in religions such as Buddhism and Judaism. In fact, a lack of access to abortion services actually goes against some religions. This is important to note because it essentially means that when the government starts getting involved in abortion access, church is no longer separated from state, and some people's religious beliefs get prioritized while other people's get taken away. This violates first amendment rights to freedom of religion and belief).
It has been proven repeatedly that restricting access to abortion DOES NOT reduce the incidence of it. It only reduces the incidence of safe abortion. (This is vitally important, especially when considering the pro-life push for total abortion bans. There are very empathetic and well-intentioned people at the heart of the pro-life movement, so it needs to be recognized and accepted that, based on very consistent evidence, there will never be an end to abortion. There will always be pregnant women desperate enough to attempt to have an abortion through any means possible. This should be just as (if not more) upsetting to those who are pro-life as the concept of abortion is, as it puts not just one but two potential lives at risk. Abortion will never end, more women (especially vulnerable women) will just suffer. Abortion can, however, be reduced through other means such as education and birth control.
Key Facts About the Constitution:
The First Amendment of the US Constitution states that "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances."
In other words, all Americans are free to their own beliefs, and the federal government has no business restricting said beliefs or forcing one specific belief on the people.
Key Facts About Pro-Life:
To be pro-life is to believe that life begins at the moment of conception and that abortion is therefore murder, so no person should ever have the right to one.
As I've already mentioned, the first part of this stance is perfectly acceptable - everyone is entitled to their own beliefs on personhood, and if those who identify as pro-life want to try to reduce abortions by educating women on birth control, fetal development, etc. then that is completely valid and ethical.
The problem with the pro-life movement is the second part of the stance, or the idea that no woman should be entitled to an abortion because it is murder. Don't get me wrong, I can definitely empathize with the desire to give a voice to the unborn. But to force all conceptions to be carried full term to birth based on one single belief raises a huge ethical dilemma. Pro-life and pro-choice cannot see eye-to-eye because those who are pro-life define this debate as one about murder (or when life begins), while pro-choice defines this debate as one about belief.
When life begins is a belief.
Read that again.
Whether one's belief on personhood is based solely in religion, solely in science, or in a combination of both, it is still a belief, not a fact. And there are multiple ethically acceptable beliefs to this debate, hence why it is a debate. There is more than one answer, it is not black and white. We are not debating life independent of another human being's body (which the termination of would very obviously be murder). We are debating potential to that independent life, which makes this much more gray.
Abortion therefore boils down to belief. The terms can be interchangeable. So for the pro-life movement to say that no pregnant woman should have the right to an abortion is to say that no woman should have the right to her own beliefs on when life begins. It is to say that only one belief is acceptable.
Key Facts About Pro-Choice:
Pro-choice, on the other hand, is the refusal to accept and force just one single belief on when life begins on all other individuals. Pro-choice is the opposite of pro-life because it allows for the freedom of belief. Pro-choice is simply pro-you-are-entitled-to-whatever- religious-and/or-scientific-definition-of-life-you-choose-within-reason- as-long-as-it-does-not-take-that-same-freedom-away-from-others.
Anyone who does not force their personal belief of when life begins onto other people's minds and bodies is therefore pro-choice. This includes people who say "I am pro-life for me and pro-choice for others." This is the same as pro-choice because it means believing whatever definition of life you want, but not forcing it onto others.
Roe v. Wade gave all women the same right to their own personal beliefs on when life begins, and therefore a right to abortion. By overturning Roe, the predominantly pro-life Supreme Court has essentially decided that states can now force one single belief on when life begins on an entire group of people. This is, by definition, unconstitutional. With abortion laws being in state hands, the overturning of Roe has raised the question of who gets freedom to their own beliefs. And the answer is women in blue states and women who have the ability to cross states lines. All other women (mostly minority and low-income/poor women) are excluded from this and are therefore being forced to abide by pro-life beliefs, further exacerbating their circumstances.
If there is one thing I want the pro-life movement to understand, it is that this unethical forcing of one belief onto all others is not a win. As previously mentioned, evidence repeatedly shows that abortion bans do not stop abortions. The unborn have not been saved with the overturning of Roe. Rather, more lives are now at risk. Even if those who are pro-life refuse to see this issue as one of freedom of belief, they should at least consider the fact that these bans do not save the unborn, and are therefore in vain. We have the same common goals: to reduce the need for abortions and support vulnerable women. There are more effective ways to do this than through abortion bans.
Sources:
- Fetal development: https://medlineplus.gov/ency/article/002398.htm
- Fetal pain: https://pubmed.ncbi.nlm.nih.gov/16118385/
- Fetal consciousness: https://pubmed.ncbi.nlm.nih.gov/19092726/
- Abortion information and statistics: https://www.plannedparenthood.org/uploads/filer_public/b3/8c/b38c6365-2337-4576-b07d-6a56cbf42ed2/ppst_abortion_facts.pdf
- First Amendment: https://constitution.congress.gov/constitution/amendment-1/











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