Life Inside The Womb: First-trimester Vs. Late-term Abortions

I first published this article on a mainstream online platform, and it got a fair amount of reads, but I wanted to share it on our website, so I had to delete it from that platform in order to protect my identity.

When writing this piece, my objective was to provide an evidence-based, unbiased summary of fetal development related to abortion timing, and I received feedback that it accomplished its purpose. So, if you are looking for a neutral starting point for a discussion on this topic, no matter what side of the argument you are in, it would be worth looking at this article.

I’ve been following the abortion debate and, as a healthcare professional, I’ve seen first-hand the impact of abortions in young women.

I would like to share with you some objective insight into what exactly exists inside of the womb, and its survival potential at both the first trimester (the traditionally preferred time to perform abortions), and third trimester (the newly announced period for abortions in New York and Virginia).

When do first-trimester abortions really occur?

The most frequently used way of calculating the age of an embryo is by the date of the last menstrual period (LMP). Let’s say that a woman had her period on a specific day, then about 14 days later she ovulated and somehow the egg that her body released during ovulation got fertilized by a sperm.

Two weeks after that, she is supposed to get her period, but she doesn’t. She waits a couple of days before getting worried because not every month her menstruation will show in the exact same day. If she has no reason to suspect that she is pregnant, the woman will wait more before taking a pregnancy test, and if she has an irregular period, she could wait for one or even two weeks before thinking about pregnancy.

This means that, most likely, a woman will know for sure that she is pregnant at about 2.5 weeks of embryonic development, and by the time she decides and gets to perform an abortion, the embryo will be, at the least, at week 3 of development, when the spinal chord and the heart start to form.

I would assume that, on average, a woman would have an abortion at four weeks if she were very firm and quick about it, but Planned Parenthood statistics (1) say that 66% of first trimester abortions occur in the first eight weeks, and 92% within the first 13 weeks. So, we could average that most abortions are performed at week 10 when an embryo has already become a fetus.

What happens during the first trimester inside the womb?

As it reads in the UNSW embryology database, “90% of the adult anatomical structures have formed” (2) by week 8, including the brain and heart. At week 10, all systems are functioning, and it’s just a matter of growth and specialization of the organs to mature.

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Fetus at 10 weeks of pregnancy (Image from UNSW Embriology)

But there’s a technical concept to consider. Although Planned Parenthood refers to 13 weeks as the first trimester, they don’t specify how they calculated this. It would belong to the first trimester if they calculated it by LMP, but if they did this by direct observation of the fetus (which they have all the means to do) or ultrasound, 13 weeks could belong to the second trimester.

Either way, by 13 weeks, the baby starts forming bone, and if we were to take an x-ray of the mother, both the mom’s bones and the fetus’ skeleton would show up; also, the already developed organs keep growing, and the head is getting straight. However, the fetus is still unable to survive out of the womb at this age.

Between 11–14 weeks is also the time when most fetal abnormalities start to develop and can be detected by screening. Some of them can be treated successfully by fetal (in utero) surgery, which can be done as early as week 24. (3,4)

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Fetal surgery (Image from Koehler et al.)

How late is late-term?

According to the US government (5), late-term abortion is that performed after 24 weeks. By then, the fetus is already fully formed, with senses developed, including hearing, vision, touch, and the rest of the nervous system.

At this point, the weight is about 1,000 grams, and for the organs to get to their maximum potential, it’s just a matter of maturation, which can happen inside or outside of the uterus under the right conditions. The face is already the way it’s going to look at birth, and girls are already growing eggs in their ovaries at only 24 weeks of fetal development.

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Fetus at 30 weeks of pregnancy (Image from

What is done for the mother’s health in the third trimester?

There are not many situations in which pregnancy is the primary cause of health problems for the mother. High-risk pregnancies are due mostly to conditions that the mother had before the pregnancy, or that she developed independently of her pregnant state.

Those conditions that are directly caused by the pregnancy are most commonly high blood pressure and diabetes, both with standard proven treatments, and that resolve once the baby is born. In the rare case that the mother gets to a point where her life is at risk, induction of labor or an emergency cesarean section are indicated. The same concept applies to pregnancies with multiple babies, and when there are abnormalities of the placenta that could risk the mother’s and the newborn’s life.

Can a baby survive out of the womb at 24 weeks?

It’s now well-known that in case of emergency cesarean section, or preterm labor, a baby can survive out of the womb from as early as 22 weeks. Sharp et al. (6) published in 2018 a documentation of 159 preterm births that occurred from 22 to 24 weeks; the results were that “5% of live births survived at 22 weeks, 46% at 23 weeks and 77% at 24 weeks.” A significant 76% of these kids didn’t develop moderate or severe disability by the age of 5, and 55% were completely free from any disability.


I hope this helps to clarify some misconceptions on the topic of abortions and to give a clear picture of the stages in which these are being performed.

If you learned something new from this post, or if it helped to reaffirm or change your position about abortions, please share in the comments below.

Dr. B. – Conservative Midwives Organization

Facts Checker

  1. Planned Parenthood — Abortion After The First Trimester in the United States
  2. UNSW Embryology — Fetal Development
  3. Maselli et al. — Advances in fetal surgery
  4. Koehler et al. — The Evolution of Fetal Surgery
  5. Insider — President Trump called for a ban on ‘late-term abortion’ in the State of the Union. Here’s what you should know about the procedure.
  6. Sharp et al. — Survival and neurodevelopmental outcomes in extremely preterm infants 22–24 weeks of gestation born in Western Australia.
  7. WebMD — Managing a High-Risk Pregnancy
  8. Gray’s Anatomy (1918 ed.) — The Form of the Embryo at Different Stages of Its Growth
Dr. B.
Dr. B.

Founder of the Conservative Midwives Organization

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