By SUSAN ADELMAN, MD
When lawyers and legislators talk about abortion, they often struggle to define viability, but the matter is much more complicated than most of them acknowledge. The classic Supreme Court case Roe versus Wade claims that viability starts at the third trimester, which they interpret as meaning 28 weeks gestation. British law has settled on 24 weeks. American state laws vary from 20 to 25 weeks. The problem is that whether or not a fetus would be viable outside of the womb depends on many factors.
The American College of Obstetrics and Gynecology explains that “many other factors…influence viability, such as sex, genetics, weight, circumstances around delivery, and availability of a neonatal intensivist health care professional.” But that just scratches the surface, since some babies could never be viable, such as ectopic pregnancies. Other babies would be viable if born in a major medical center with a superb neonatal unit, but not so much in a small town with no such facility.
Moreover, the goal posts keep moving. Babies who correctly would have been judged nonviable years ago have a far better prognosis today because of the many advances in neonatology. A literature search shows how much things have changed since I began my career as a pediatric surgeon in the early 1970s. Back then, I remember seeing a 1,300-gram baby and being told that he was at the limit of viability. When I closed my practice 20 years ago, 700-gram babies often went to the operating room for major surgery. I still remember a controversy that I had with a referring neonatologist over whether or not to operate on a 600-gram baby who probably would need a major bowel resection.
What ages are we talking about? In general, a 23-week fetus is 1.25 pounds (567 grams); a 24-week fetus 1.48 pounds (671 grams), and a 25-week fetus is 1.73 pounds (784 grams). Understand though that these weights vary, due to many factors. What are the survivals? The ACOG website writes “rates of neonatal survival to discharge at this time range dramatically from 23% to 27% for births at 23 weeks, 42% to 59% for births at 24 weeks, and 67% to 76% for births at 25 weeks of gestation. The consensus also notes that deliveries before 23 weeks have a 5–6% survival rate and that significant morbidity is universal (98–100%) among the rare survivors.” Despite all this, more and more politicians are discussing a 15 week ban with exceptions. Where did that number come from?
What kind of support do these ultra-tiny newborns require in order to survive? Since newborns are not able to suckle from a bottle or breast until about 34 weeks, at first they are nourished in the neonatal unit by I.V. and tube feeding. Some need mechanical respiratory support in their early weeks, and some need oxygen for much longer. All very tiny preemies are nursed in incubators that maintain a constant temperature and humidity. Neonatologists monitor their progress, blood sugar, bilirubin and other parameters with regular blood testing. Without all this special care, the smallest would not survive.
So, the very smallest of these preemies are viable only with a high level of care, right? Yes. Does that still allow them to be called viable neonates? Yes, with optimal care, but state laws vary. For instance, as recently as 2006, Kansas defined viability as the capacity to survive after birth, “without the use of extraordinary measures,” whatever that means. At least this is better than some laws that attempt to prohibit abortion after a heartbeat can be detected, which only is about 6–8 weeks from conception. That, especially if combined with a rule that prohibits exceptions – in the case of incest, when survival of the mother is endangered, or in the case of rape – simply becomes a ban on abortion, period.
I really do not know what the majority of Americans favor. Perhaps the best way to find out is to watch state laws evolve. In Michigan, Proposition 3 passed in 2022, adding the following language to the state constitution “the state cannot under any circumstances prohibit an abortion that, in the professional judgment of an attending health care professional, is medically indicated to protect the life or physical or mental health of the pregnant individual.” This year, the Reproductive Health Act -a package consisting of three Senate bills and four House bills – has been working its way through the legislature, making additional changes in existing laws and in the constitution.. Readers may find them at Revised Summary as Introduced (9/14/2023) (mi.gov). It is noteworthy that the RHA will “repeal or amend sections of law that now prohibit or direct the use of public funds related to abortion.’ Many other worthy points are covered in the summary.
Not everybody will be happy with their state laws. Some families may move away to states whose abortion laws better conform with their religion and code of values. All we as doctors can do is to be sure that those who need to make painful decisions will know the facts, as we have laid them out above, and as they continue to evolve with the growth of medical knowledge.