Since abortion became legal in the United States in 1973, the topic has raised strong emotions in both political and medical debates. More recently, 11 states have passed a bill called the Pain-Capable Unborn Child Protection Act. On May 13, 2015, the US House of Representatives also passed a ban on abortions after 20 weeks of fertilization. [Editor's note: The bill defines 20 weeks as 20 weeks post-fertilization, equal to 22 weeks after the last menstrual period.] Some members of the medical community are offended at the intrusion of government into the physician-patient relationship, while others appreciate the government's role in protecting the interests of its citizens and promoting the highest standards of medical care.
Roe v. Wade permitted abortion without restriction in regard to gestational age. Even advocates of abortion rights are often surprised to learn that this court decision permitted abortion through all 9 months of pregnancy. Despite one's position on elective abortion, the concept of termination of a fetus after viability is repulsive to a great number of individuals. Subsequently, many states began restricting abortions around the definition of viability, although some states still permit late-term abortions. While the political debate carries on, the definition of viability keeps getting pushed earlier as neonatal science advances. The New England Journal of Medicine recently reported a survival rate of about 23% for actively resuscitated neonates born at 22 weeks.*
Fetal Pain as a Guideline
Why, then, should fetal pain be used as a guideline for abortion restriction? Our culture prides itself on caring for creatures that are suffering. A variety of laws have been passed restricting cruelty to animals, for example. During a discussion I had with one Nebraska legislator promoting a Pain-Capable Unborn Child Protection Act, he revealed his opinion that in a civil society, laws are passed to protect many creatures from pain. His belief was that this principle should also be extended to the smallest and weakest members of the human community: the fetus within the womb.
So does the fetus, in fact, feel pain? A growing body of evidence says yes. The fetus is known to have pain receptors throughout the body by 8 weeks of gestation. By 20 weeks gestational age, the fetus will react to a painful stimulus in the same manner that adults do. A stress response to needling of the fetal tissue with production of beta endorphins, cortisol, and noradrenaline can be seen by 20 weeks gestational age. The same response is not seen when needling the umbilical cord, which does not contain pain fibers. Some researchers argue that cortical function is required for pain sensation and that this is not functional until 29-30 weeks gestational age. The presumption is that pain cannot be perceived until neural fibers connect the thalamus to the cortex, a process usually not completed until this time. There is evidence, however, that the thalamus is capable of integrated nociception, which can explain the pain response in anencephalic children and those without an intact cortex.
The science of the development of the pain pathways in the fetus is not in question. What is in question is whether a conscious experience with cortical integration is necessary to call the reaction to noxious stimuli "pain." It is clear at a very early gestational age that the fetus is responding to its environment and that the fetus produces an integrated response to painful stimuli by 20 weeks gestational age. What is observed is a normal human response to pain. What is perceived by another individual cannot be known.
A Physician's Role
What, then, is the responsibility of the physician? Women deserve full disclosure of our scientific understanding of the state of the fetus within their wombs. Our patients should know that the heart begins to beat at 21 days gestation and that the fetus responds to touch by 8 weeks. They should be given the opportunity to see their fetus moving inside the uterus by ultrasound. They should know that viability is a moving target that continues to be moved earlier and earlier in gestation based on our advancing science. Therefore, viability should not be the defining factor of our humanity or right to live. They should also know that the pathways are present for the fetus to respond to pain by 20 weeks gestational age.
For more information about fetal pain, please visit www.doctorsonfetalpain.com.
[Editor's note: Click here to read a counter-commentary from the American Congress of Obstetricians and Gynecologists.]
*Correction: An earlier version of this commentary incorrectly stated that the neonates survived without severe impairment.
Medscape Ob/Gyn © 2015 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Anita L. Showalter. A Growing Body of Research Shows That Fetuses Can Feel Pain - Medscape - May 27, 2015.