What Science Reveals about Fetal Pain

What Science Reveals about Fetal Pain

By Arina Grossu Director, Center for Human Dignity

A growing body of science reveals an undisputable fact: unborn babies can feel pain by 20 weeks post-fertilization, [i] and most likely even earlier. As the medical community continues to increase its understanding of fetal pain, there have also been increasing legislative efforts to protect the unborn child from cruel suffering.

Pain (nociception) is an aversive response to a physically harmful or destructive stimulus. The National Institutes of Health define pain as “a basic bodily sensation that is induced by a noxious stimulus, is received by naked nerve endings, is characterized by physical discomfort (as pricking, throbbing, or aching), and typically leads to evasive action.” [ii]

Unborn babies 20 weeks post-fertilization not only have the anatomy to process pain but also the neurobiology to transmit painful sensations to the brain and perceive pain. Dr. Jean A. Wright, testifying at a Congressional subcommittee hearing summarized it best:

After 20 weeks of gestation [18 weeks post-fertilization], an unborn child has all the prerequisite anatomy, physiology, hormones, neurotransmitters, and electrical current to “close the loop” and create the conditions needed to perceive pain…The development of the perception of pain begins at the sixth week of life. By 20 weeks [18 weeks post-fertilization], and perhaps even earlier, all the essential components of anatomy, physiology, and neurobiology exist to transmit painful sensations from the skin to the spinal cord and to the brain. [iii]

There is no question, biologically speaking, about whether an unborn child can feel pain by 20 weeks post-fertilization. By 18 weeks post-fertilization, nerves link pain receptors to the brain’s thalamus (the pain processing center). By 18 weeks post-fertilization, the cerebral cortex (the region of the brain associated with higher mental functions) has acquired a full complement of neurons, meaning all of the neurons are present, though not all the connections in the cortex are fully developed until later. EEG activity, a recording of electrical activity in the brain, appears for the first time at 18 weeks post-fertilization, showing the integrity of the circuitries of the cortex and the thalamus. [iv]

Some scientists take an agnostic position on whether the unborn child consciously experiences pain by 20 weeks post-fertilization and they argue this based on a theory that a mature cerebral cortex is necessary for the conscious perception of pain. However, a mature cerebral cortex is not necessary in order for the unborn child to feel pain, as evidenced by scientific studies and observations that both children and adults who are born with no or minimal cerebral cortex, do in fact still perceive pain.

observation that unborn children who are not given anesthesia elicit a hormonal stress response to painful stimuli, which is alleviated by the effects of anesthesia as it is in adults.The instruction of medical textbooks and accepted common medical practice is to administer fetal anesthesia before an in-utero surgery on the unborn child around 20 weeks post-fertilization. The common practice is based on the science of fetal development and the

A 2015 study in Trends in Anesthesia & Critical Care also advises that pain relievers (analgesia) be administered to the mother and child following an in-utero surgery. The post-operative suffering from pain leads to fetal and maternal stress by causing uterine contractions. Appropriate treatment of postoperative pain is to give pain relievers in order to avoid triggering premature contractions and premature birth.

A January 2015 anesthesia clinical review book contained a chapter on fetal intervention and stated, “The fetus is able to mount a physicochemical stress response to pain starting around 18 weeks of gestation. It becomes capable of experiencing pain between 20 and 30 weeks of gestation [18 and 28 weeks post-fertilization].” [v]

Legislation that addresses fetal pain must be based on the indisputable biology, scientific data, and physical evidence of fetal pain and not on political, religious, theoretical, or philosophical ideas about self-consciousness or self-awareness. The bottom line is that an unborn child can and does feel pain by 20 weeks post-fertilization. Fetal pain mechanisms are in place at that time.

Polling shows that the majority of Americans agree on setting abortion bans, such as the Pain-Capable Unborn Child Protection Act, to protect the almost 13,000 American pain-capable unborn children who die from late abortion each year. [vi]



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[i] Fetal age can be given as age “post-fertilization” meaning the time from conception, or gestational age meaning the time since the last menstrual period (LMP), which is usually easier to determine and occurs approximately two weeks before ovulation and fertilization. Thus gestational age will be 2 weeks older than post-fertilization age, i.e., 22 weeks gestation = 20 weeks post-fertilization.

[ii] See definition “b” at: Merriam-Webster Medical Dictionary, accessed on May 12, 2014, http://www.merriam-webster.com/medlineplus/pain.

[iii] Dr. Jean A. Wright, professor and chair of Pediatrics at Mercer School of Medicine, in a testimony before the House of Representatives. Committee on the Judiciary. Pain of the Unborn: Hearing Before the Subcommittee on the Constitution. 109th Cong., 1st Sess., 2005.

[iv] S. Vanhatalo and O. van Nieuwenhuizen, “Fetal Pain?,” Brain & Development 22(2000): 145-150.

[v] Linda S. Aglio, Robert W. Lekowski, Richard D. Urman, eds., Essential Clinical Anesthesia Review: Keywords, Questions and Answers for the Boards (Cambridge University Press, 2015), 399.

[vi] “Induced Abortion in the United States,” Guttmacher Institute, July 2014, accessed January 17, 2015, http://www.guttmacher.org/pubs/fb_induced_abortion.html.