Fetal pain
Neonatal perception is the study of the extent of somatosensory and other perceptual system
Perceptual system
A perceptual system is a computational system designed to make inferences about properties of a physical environment based on scenes. Other definitions may exist....

s during pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

. In practical terms, this means the study of fetus
A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...

es; none of the accepted indicators of perception are present in embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...


Medical studies and reviews

The hypothesis that human fetuses are capable of perceiving pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...

 has not received sufficient evidence to be proven or disproven; the developmental stage of research and instrumentation is so far insufficient to this task. The issue is considerably complicated by the usual difficulties in perceptual research of unresponsive subjects: "Though techniques such as positron electron tomography scanning might reveal those parts of the brain that respond to a painful stimulus, this does not tell us what the individual is experiencing."

The accepted hypothesis of the means by which pain is perceived states that it requires certain physical structures and operations. These are not formed in fetuses until 30 weeks or more. The consensus of the scientific community at this time is that only fetuses of this age or older are capable of perceiving pain.

Researchers from the University of California, San Francisco
University of California, San Francisco
The University of California, San Francisco is one of the world's leading centers of health sciences research, patient care, and education. UCSF's medical, pharmacy, dentistry, nursing, and graduate schools are among the top health science professional schools in the world...

 in the Journal of the American Medical Association
Journal of the American Medical Association
The Journal of the American Medical Association is a weekly, peer-reviewed, medical journal, published by the American Medical Association. Beginning in July 2011, the editor in chief will be Howard C. Bauchner, vice chairman of pediatrics at Boston University’s School of Medicine, replacing ...

concluded in a meta-analysis
In statistics, a meta-analysis combines the results of several studies that address a set of related research hypotheses. In its simplest form, this is normally by identification of a common measure of effect size, for which a weighted average might be the output of a meta-analyses. Here the...

 of data from dozens of medical reports and studies that fetuses are unlikely to feel pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...

 until the third trimester of pregnancy. There is 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. Because pain can involve sensory, emotional and cognitive factors, it may be "impossible to know" when painful experiences are perceived, even if it is known when thalamocortical connections are established.

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.

Also in 2005, Mellor and colleagues reviewed several lines of evidence that suggested a fetus does not awaken during its time in the womb. Mellor notes that much of the literature on fetal pain simply extrapolates from findings and research on premature babies. He questions the value of such data:
Systematic studies of fetal neurological function suggest, however, that there are major differences in the in utero environment and fetal neural state that make it likely that this assumption is substantially incorrect.
He and his team detected the presence of such chemicals as adenosine, pregnanolone, and prostaglandin
A prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body. Every prostaglandin contains 20 carbon atoms, including a 5-carbon ring....

-D2 in both human and animal fetuses, indicating that the fetus is both sedated and anesthetized in the womb. These chemicals are oxidized with the newborn's first few breaths and washed out of the tissues, allowing consciousness to occur. If the fetus is asleep throughout gestation then the possibility of fetal pain is greatly minimized. “A fetus,” Mellor told the NYTimes, “is not a baby who just hasn’t been born yet.”

There is also discussion among researchers about how pain is perceived over-all. Some researchers believe that because pain can involve sensory, emotional and cognitive factors, pain may not be sensed until after birth.

In 2001, a working group of the Medical Research Council (UK)
Medical Research Council (UK)
The Medical Research Council is a publicly-funded agency responsible for co-ordinating and funding medical research in the United Kingdom. It is one of seven Research Councils in the UK and is answerable to, although politically independent from, the Department for Business, Innovation and Skills...

 in the United Kingdom called for more research regarding fetal pain. According to the Daily Telegraph, Eve Johnstone, the chair of that working group
"makes a strong case for additional research." Ms. Johnstone told the newspaper, "We ought to study this carefully."

Though many researchers in the area of fetal development agree a fetus is unlikely to feel pain until after the seventh month of pregnancy, developmental neurobiologists suspect that the establishment of thalamocortical connections (at about 26 weeks) may be critical to fetal perception of pain.

Fetal pain and abortion

Scientific research generally indicates that the fetus is incapable of feeling pain until at least the 24th week. Many pro-life activists strongly believe in the ability of a fetus to perceive pain, and have introduced legislation in line with this belief. However, fetal pain is not a major legal issue in the debate about abortion
Abortion is defined as the termination of pregnancy by the removal or expulsion from the uterus of a fetus or embryo prior to viability. An abortion can occur spontaneously, in which case it is usually called a miscarriage, or it can be purposely induced...

, and has not been a deciding factor in any US Supreme Court decision, including the 1973 Roe v. Wade
Roe v. Wade
Roe v. Wade, , was a controversial landmark decision by the United States Supreme Court on the issue of abortion. The Court decided that a right to privacy under the due process clause in the Fourteenth Amendment to the United States Constitution extends to a woman's decision to have an abortion,...


Such legislation, if passed would likely affect a very small percentage of abortion
Abortion is defined as the termination of pregnancy by the removal or expulsion from the uterus of a fetus or embryo prior to viability. An abortion can occur spontaneously, in which case it is usually called a miscarriage, or it can be purposely induced...

s, as most are performed before week 20.

Medical objections

Medical objections to fetal pain legislation has been raised on a number of grounds. Some caution that unnecessary use of fetal anesthetic may pose potential health risks to the prospective mother.
In the context of abortion, fetal analgesia would be used solely for beneficence toward the fetus, assuming fetal pain exists. This interest must be considered in concert with maternal safety and fetal effectiveness of any proposed anesthetic or analgesic technique. For instance, general anesthesia increases abortion morbidity and mortality for women and substantially increases the cost of abortion. Although placental transfer of many opioids and sedative-hypnotics has been
determined, the maternal dose required for fetal analgesia is unknown, as is the safety for women at such doses.

In any event, anesthesia may be unnecessary, as the fetal brain is awash in naturally occurring chemicals that keep it sedated and anesthetized until birth.

Anesthesia researcher, Laura Myers, has suggested the fetal pain legislation may make abortions harder to obtain; because, abortion clinics lack the equipment and expertise to supply fetal anesthesia. Currently, anesthesia is administered directly to fetuses only while they are undergoing surgery.

United Kingdom

In March 2010, the Royal College of Obstetricians and Gynecologists submitted a report, Fetal Awareness - Review of Research and Recommendations for Practice, concluding that "Current research shows that the sensory structures are not developed or specialized enough to respond to pain in a fetus of less than 24 weeks", pg. 22.
The neural regions and pathways that are responsible for pain experience remain under debate but it is generally accepted that pain from physical trauma requires an intact pathway from the periphery, through the spinal cord, into the thalamus and on to regions of the cerebral cortex including the primary sensory cortex (S1), the insular cortex and the anterior cingulated cortex.3,4 Fetal pain is not possible before these necessary neural pathways and structures (figure 1) have developed. -pg. 3
The report specifically identified the anterior cingulate as the area of the cerebral cortex responsible for pain processing. The anterior cingulate is part of the cerebral cortex
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...

, which begins to develop in the fetus at week 26.

In 2006, an opinion piece by Stuart Derbyshire in the British Medical Journal concluded that pain is dependent upon cognitive and emotional developments that occur after birth:
In 1996, physiologist Peter McCullagh spoke on behalf of a pro-life
Opposition to the legalization of abortion is centered around the pro-life, or anti-abortion, movement, a social and political movement opposing elective abortion on moral grounds and supporting its legal prohibition or restriction...

 group to the British Parliament. He said, "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 response, Wendy Savage Press officer, Doctors for a Woman’s Choice on Abortion, pointed out that the majority of surgical abortions in Britain are already performed under general anesthesia, which also affects the fetus. In a letter to the British Medical Journal,April 1997, she deemed the discussion "unhelpful to women and to the scientific debate."

United States

In the 108th Congress, Senator Sam Brownback
Sam Brownback
Samuel Dale "Sam" Brownback is the 46th and current Governor of Kansas. A member of the Republican Party, he served as a U.S. Senator from Kansas from 1996 to 2011, and as a U.S. Representative for Kansas's 2nd congressional district from 1995 to 1996...

 introduced a bill called the "Unborn Child Pain Awareness Act" for the stated purpose of "ensur[ing] that women seeking an abortion are fully informed regarding the pain experienced by their unborn child.", which was read twice and referred to committee. Subsequently 25 states have examined similar legislation related to fetal pain and/or fetal anesthesia, and in 2010Nebraska
Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....

 banned abortions after 20 weeks on the basis of fetal pain. Eight states, Arkansas, Georgia, Louisiana, Minnesota, Oklahoma, Alaska, South Dakota, and Texas have passed laws which introduced information on fetal pain in their state-issued abortion-counseling literature, which one opponent of these laws, the Guttmacher Institute
Guttmacher Institute
The Guttmacher Institute is a non-profit organization which works to advance sexual and reproductive health. The institute operates in the United States and globally "through an interrelated program of social science research, policy analysis and public education." According to their mission...

 founded by Planned Parenthood, has called "generally irrelevant" and not in line "with the current medical literature". Dr. Arthur Caplan
Arthur Caplan
Arthur L. Caplan, Ph.D., is Emmanuel and Robert Hart Professor of Bioethics and director of the Center for Bioethics at the University of Pennsylvania. Prior to coming to Penn in 1994, Caplan taught at the University of Minnesota, the University of Pittsburgh, and Columbia University. He was the...

, director of the Center for Bioethics at the University of Pennsylvania, said laws such as these "reduce... the process of informed consent to the reading of a fixed script created and mandated by politicians not doctors."

External links

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