Fetal pain

Fetal pain, its existence, and its implications are debated politically and academically, particularly in regards to the abortion debate.

Overview
Whether a fetus has the ability to feel pain and to suffer is part of the abortion debate. Determining the stage of pregnancy at which a fetus is able to feel pain or suffering could have a significant effect on the abortion debate as well as abortion laws and practices. For example, legislation has been proposed requiring abortion providers to tell a woman that the fetus may feel pain during the abortion procedure, and requiring her to accept or decline anesthesia for the fetus.

A lack of fetal pain does not necessarily "resolve the question of whether abortion is morally acceptable or should be legal". Still unresolved would be whether "the obligation not to harm other human subjects extends considerably beyond that of not causing pain."

Most scientists believe that a fetus is able to feel pain sometime during the pregnancy, often beginning less than 24 weeks after conception, although the question of exactly when pain might be possible is disputed. Some academics argue that it appears as early as seven weeks after conception. Others claim that pain cannot be felt until the third trimester of pregnancy or until after birth.

There may be an "emerging consensus among developmental neurobiologists that the establishment of thalamocortical connections" (at about 26 weeks) is a critical event with regard to fetal perception of pain. Nevertheless, because pain can involve sensory, emotional and cognitive factors, it is "impossible to know" when painful experiences may become possible, even if it is known when thalamocortical connections are established. According to Arthur Caplan, "there is no consensus among the medical and scientific experts about precisely when a fetus becomes pain-capable. Some put the point at 28 weeks. Others say 26 or 24 and still others younger still."

Multiple nerve systems are involved in the sensation of pain and nociception. When the brain and nervous system are fully developed, the sensation is triggered by nociceptors reacting to some stimulus. The resulting signal travels via the peripheral nervous system to nociceptors associated with the spinal column. It then travels up the spinal column to the thalamus, and onward to the cerebral cortex, where it is finally interpreted as a painful sensation. Pain "may exist even in the absence of physical stimuli," and conversely "nociception without pain" exists as well. Some scientists believe "the cortex is not required for conscious sensory perception."

Early in development, from about 12-18 weeks gestation, there is a complete link from the periphery to the thalamus in the brain, and the fetus shows clear evidence of defensive reactions against tissue damage including hormonal and hemodynamic responses. After about 26 weeks gestation there is a complete link from the thalamus to the cortex of the brain. Cortical responses in premature babies of about 25 weeks gestation have been recorded during the usual heel lance procedure performed shortly after birth (for blood sampling). In summary, there is good evidence that from about 26 weeks gestation the fetal brain can be considered a functional unit capable of processing noxious sensory input, and pain before that point may also be possible.

Medical opinions
In 1980, Stanislav Reinis and Jerome Goldman wrote that, "The first detectable brain activity in response to noxious stimuli occurs in the thalamus between the ninth and tenth weeks."

In 1984, anesthesiologist Vincent J. Collins wrote: "because the requisite neurological structures are present at that time and because they are functioning, as evidenced by the aversive response of the human fetus, it may be concluded with reasonable medical certainty that the fetus can sense pain at least by 13 ½ weeks." Dr. Collins was one of several scientists who wrote an open letter to President Reagan, asserting that, "The ability to feel pain and respond to it is clearly not a phenomenon that develops de novo at birth....by the close of the first trimester the fetus is a sentient, moving being."

A 1988 study observed changes in heart rates and hormonal levels of newborn infants after circumcision, blood tests, and surgery — effects which were alleviated with the administration of anesthesia.

In 1995, Dr. Robert J. White, director of the Division of Neurosurgery and Brain Research Laboratory at Case Western Reserve School of Medicine and a member of the Vatican's Pontifical Academy of Sciences, gave testimony before the House Constitution Subcommittee of the Congress of the United States. He stated that, at 20 weeks' gestation, the fetus "is fully capable of experiencing pain...Without question, all of this is a dreadfully painful experience for any infant subjected to such a surgical procedure."

In 1996, developmental physiologist Peter McCullagh wrote: "At what stage of human prenatal development are those anatomical structures subserving the appreciation of pain present and functional? The balance of evidence at the present time indicates that these structures are present and functional before the tenth week of intrauterine life."

In 1997, Dr. Paul Ranalli, a neurologist at the University of Toronto, cited several observations to support the belief that a fetus can experience pain, including observing a fetus "withdraw from painful stimulation", and the fact that stress hormones detected in pain-stricken adults have also been found in the blood samples of aborted fetuses. Dr. Ranalli is a member on the Advisory Board of the deVeber Institute for Bioethics and Social Research, a pro-life organization. The group Canadian Physicians for Life cites Ranalli for the proposition that, "enough development has occurred by 12-14 weeks that some pain perception is likely."

Also in 1997, a "Working Party" appointed by the Royal College of Obstetricians and Gynaecologists, a medical group in the United Kingdom, stated that "very early in pregnancy fetuses will react to stimuli, but that reaction does not in itself provide any evidence that the fetus experiences those stimuli." The Working Party further stated that, "Little sensory input" reaches the brain of the developing foetus before 26 weeks, and "therefore reactions to noxious stimuli cannot be interpreted as feeling or perceiving pain."

In 1999, it was noted in the British Journal of Obstetrics and Gynaecology that, "The first neurones to link the cortex with the rest of the brain are monoamine pathways, and reach the cortex from about 16 weeks of gestation. Their activation could be associated with unpleasant conscious experience, even if not pain."

In 2001, a working group of the Medical Research Council (UK) in the United Kingdom suggested that doctors should consider the use of analgesia and sedation for fetuses over 24 weeks of age undergoing surgery. Dr. Eve Johnstone, the chair of that working group, told The Daily Telegraph that a fetus was aware of pain by 24 weeks, maybe as early as 20 weeks, because "[c]onnections from the thalamus to the cortex begin to form at about 20 weeks gestation." Dr. Susan Dudley of the National Abortion Federation in the U.S. responded: "The obvious and most important thing to say is most abortions take place before 20 weeks."

In 2005, Mellor and colleagues reviewed several lines of evidence that suggested a fetus does not awake during its time in the womb. If the fetus is asleep throughout gestation then the possibility of fetal pain is greatly minimised.

Later in 2005, a meta-analysis of existing experiments published in the Journal of the American Medical Association (JAMA) concluded that the limited available evidence indicates fetal perception of pain is unlikely before the third trimester, and that electroencephalography suggests the capacity for functional pain perception in premature infants probably does not exist before 29 or 30 weeks; this study asserted that withdrawal reflexes and changes in heart rates and hormone levels in response to invasive procedures are reflexes that do not indicate fetal pain. This meta-study was criticised by pro-life groups who were skeptical because of the prior involvement of several authors of the report. One directs an abortion clinic at San Francisco Hospital, while the lead author undertook legal work with NARAL Pro-Choice America for six months.

Also in 2005, the meta-study published in JAMA was criticized by K. J. S. Anand: ""The conclusions of Lee and colleagues regarding fetal pain are flawed, because they ignore a large body of research related to pain processing in the brain, present a faulty scientific rationale and use inconsistent methodology for their systematic review. Based on the available scientific evidence, we cannot dismiss the high likelihood of fetal pain perception before the third trimester of human gestation….Fetal development of the thalamus occurs much earlier than the sensory cortex, providing the substrate and mechanisms for conscious pain perception during the second trimester, but not in the first trimester....""

In November of 2005, Dr. Jean Wright testified to Congress that data "shows 16 weeks and even earlier, many of these infants feel pain and have negative outcomes from it."

In 2006, a clinical review published in the British Medical Journal concluded that pain is dependent upon cognitive and emotional developments that occur after birth: ""Theories of development assume that the early human mind begins with minimal content and gradually evolves into the rich experience of older children and adults. Although the view of a neonate as a blank slate, or tabula rasa, is generally rejected, it is broadly accepted that psychological processes have content concerning people, objects, and symbols, which lay in the first instance outside the brain. If pain also depends on content derived from outside the brain, then fetal pain cannot be possible, regardless of neural development.""

Also in 2006, a study in the Journal of Neuroscience stated: "We conclude that noxious information is transmitted to the preterm infant cortex from 25 weeks, highlighting the potential for both higher-level pain processing and pain-induced plasticity in the human brain from a very early age."