Prenatal perception is the study of the extent of

somatosensory The somatosensory system, or somatic sensory system is a subset of the sensory nervous system. The main functions of the somatosensory system are the perception of external stimuli, the perception of internal stimuli, and the regulation of bod ...

and other types of

perception Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous syste ...

during

pregnancy Pregnancy is the time during which one or more offspring gestation, gestates inside a woman's uterus. A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Conception (biology), Conception usually occurs ...

. In practical terms, this means the study of

fetus A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Pren ...

es; none of the accepted indicators of perception are present in

embryo An embryo ( ) is the initial stage of development for a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sp ...

s. Studies of this type inform the abortion controversy, along with certain related pieces of legislation in countries affected by that debate. As of 2022, there is not any

scientific consensus Scientific consensus is the generally held judgment, position, and opinion of the majority or the supermajority of scientists in a particular field of study at any particular time. Consensus is achieved through scholarly communication at confer ...

on whether a fetus can feel pain.

Prenatal hearing

Numerous studies have found evidence indicating a fetus's ability to respond to auditory stimuli. The earliest fetal response to a sound stimulus has been observed at 16 weeks' gestational age, while the auditory system is fully functional at 25–29 weeks' gestation. At 33–41 weeks' gestation, the fetus is able to distinguish its mother's voice from others.

Prenatal pain

The hypothesis that human fetuses are capable of perceiving

pain Pain is a distressing feeling often caused by intense or damaging Stimulus (physiology), stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sense, sensory and emotional experience associated with, or res ...

during the first trimester has little evidence, although fetuses at 14 weeks may respond to touch. A multidisciplinary

systematic review A systematic review is a scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from published studies on ...

from 2005 found limited evidence that thalamocortical pathways begin to function "around 29 to 30 weeks' gestational age", only after which a fetus is capable of feeling pain. In March 2010, the Royal College of Obstetricians and Gynecologists submitted a report, 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", The report specifically identified the

anterior cingulate In human brains, the anterior cingulate cortex (ACC) is the frontal part of the cingulate cortex that resembles a "collar" surrounding the frontal part of the corpus callosum. It consists of Brodmann areas 24, 32, and 33. It is involved in c ...

as the area of the

cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. It is the largest site of Neuron, neural integration in the central nervous system, and plays ...

responsible for processing of pain. The anterior cingulate is part of the cerebral cortex, which begins to develop in the fetus at week 26. A co-author of that report reviewed the evidence in 2020, specifically the functionality of the thalamic projections into the cortical

subplate The subplate, also called the subplate zone, together with the marginal zone and the cortical plate, in the fetus represents the developmental anlage of the mammalian cerebral cortex. It was first described, as a separate transient fetal zon ...

, and posited "an immediate and unreflective pain experience...from as early as 12 weeks." There is a consensus among developmental neurobiologists that the establishment of thalamocortical connections (at weeks 22–34, reliably at 29) is a critical event with regard to fetal perception of pain, as they allow peripheral sensory information to arrive at the cortex. Electroencephalography indicates that the capacity for functional pain perception in premature infants does not exist before 29 or 30 weeks; a 2005 meta-analysis states that withdrawal reflexes and changes of heart rates and hormone levels in response to invasive procedures are reflexes that do not indicate fetal pain. Several types of evidence suggest that a fetus does not awaken during its time in the womb. Much of the literature concerning fetal pain simply extrapolates from findings and research of premature babies. The presence of such chemicals as

adenosine Adenosine (symbol A) is an organic compound that occurs widely in nature in the form of diverse derivatives. The molecule consists of an adenine attached to a ribose via a β-N9- glycosidic bond. Adenosine is one of the four nucleoside build ...

pregnanolone Pregnanolone, also known as eltanolone, is an endogenous inhibitory neurosteroid which is produced in the body from progesterone. It is closely related to allopregnanolone, which has similar properties. Biological activity Pregnanolone is a pos ...

, and

prostaglandin Prostaglandins (PG) are a group of physiology, physiologically active lipid compounds called eicosanoids that have diverse hormone-like effects in animals. Prostaglandins have been found in almost every Tissue (biology), tissue in humans and ot ...

-D₂ in both human and animal fetuses, indicate that the fetus is both sedated and

anesthetized Anesthesia (American English) or anaesthesia (British English) is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prev ...

when in the womb. These chemicals are oxidized with the newborn's first few breaths and washed out of the tissues, increasing consciousness. If the fetus is asleep throughout gestation then the possibility of fetal pain is greatly minimized, although some studies found that the adenosine levels in third-trimester fetuses are only slightly greater than those in adults' blood.

Fetal anesthesia

Direct fetal

analgesia Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professionals ...

is used for only a minority of prenatal surgeries. Some caution that unnecessary use of fetal anesthetic may pose potential health risks to the 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. Given the maternal risk involved and the lack of evidence of any potential benefit to the fetus, administering fetal anesthesia for abortion is not recommended. Fetal pain legislation may make abortions more difficult 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. Doctors for a Woman's Choice on Abortion state that the majority of surgical abortions in Britain are already performed with general anesthesia, which also affects the fetus. In a letter to the ''British Medical Journal'' in April 1997, they deemed the discussion "unhelpful to women and to the scientific debate" despite a report in the ''British Medical Journal'' that "the theoretical possibility that the fetus may feel pain (albeit much earlier than most embryologists and physiologists consider likely) with the procedure of legal abortion". Yet if mothers' general anesthesia were enough to anesthetise the fetus, all fetuses would be born sleepy after a cesarean section performed in general anesthesia, which is not the case. Dr. Carlo V. Bellieni also agrees that the anesthesia that women receive for fetal surgery is not sufficient to anesthetize the fetus.

United States legislation

Federal legislation

In 1985, questions about fetal pain were raised during congressional hearings concerning the movie '' The Silent Scream''. In 2013 during the

113th Congress The 113th United States Congress was a meeting of the legislative branch of the United States federal government, from January 3, 2013, to January 3, 2015, during the fifth and sixth years of Barack Obama's presidency. It was composed of the ...

, Representative Trent Franks introduced a bill named the "

Pain-Capable Unborn Child Protection Act The Pain-Capable Unborn Child Protection Act (also colloquially known as Micah's Law) is a congressional bill that would, in most cases, make it unlawful to perform an abortion if the estimated post-fertilization age of a fetus is 20 weeks or ...

" (H.R. 1797). It passed in the House on June 18, 2013, and was received in the U.S. Senate, read twice, and referred to the Judiciary Committee. In 2004 during the

108th Congress The 108th United States Congress was a meeting of the legislative branch of the United States federal government, composed of the United States Senate and the United States House of Representatives from January 3, 2003, to January 3, 2005, durin ...

, Senator Sam Brownback introduced a bill named the " Unborn Child Pain Awareness Act" for the stated purpose of "ensur ngthat women seeking an abortion are fully informed regarding the pain experienced by their unborn child", which was read twice and referred to committee.

State legislation

Subsequently, 25 states have examined similar legislation related to fetal pain and/or fetal anesthesia, and in 2010

Nebraska Nebraska ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Ka ...

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 The Guttmacher Institute is a research and policy NGO that aims to improve sexual health and expand reproductive rights worldwide. The organization was started in 1968 as part of Planned Parenthood; it became independent from Planned Parenthood ...

founded by Planned Parenthood, has termed "generally irrelevant" and not in line "with the current medical literature".

Arthur Caplan Arthur L. Caplan (born 1950) is an American ethicist and professor of bioethics at New York University Grossman School of Medicine. He is known for his contributions to the U.S. public policy, including: helping to found the National Marrow D ...

, 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." Caplan, Arthur.
Abortion politics twist facts in fetal pain laws
''MSNBC.com'', November 30, 2005

References

External links

"Oversight Hearing on Pain of the Unborn"
from U.S. Congress, House Judiciary Committee, Subcommittee on the Constitution, Civil Rights, and Civil Liberties (2005). This includes testimony both for and against proposed legislation dealing with fetal pain.

from Ontario Consultants on Religious Tolerance. This sit

"We feel that all women considering an abortion should be fully informed and as free as possible from outside pressure." *

Anti-abortion Anti-abortion movements, also self-styled as pro-life movements, are involved in the abortion debate advocating against the practice of abortion and its Abortion by country, legality. Many anti-abortion movements began as countermovements in r ...

site presenting case for fetal pain from second month of pregnancy
HTML version
. * Statement of National Abortion Federation Opposing H.R. 3442, the "Unborn Child Pain Awareness Act" (2008)
PDF version
an

* National Right to Life Committee's webpage of testimonies regarding fetal pain

Small survivors: How the disputed science of fetal pain is reshaping abortion law
by Eric Schulzke in ''Deseret News'' {{Humandevelopment Medical ethics Pain Nociception Abortion debate Embryology