Prenatal perception

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Prenatal perception is the study of the extent of somatosensory and other types of perception during pregnancy. In practical terms, this means the study of fetuses; none of the accepted indicators of perception are present in embryos. Studies in the field inform the abortion debate, along with certain related pieces of legislation in countries affected by that debate. As of 2022, there is no scientific consensus on whether a fetus can feel pain. [1] [2] [3]

Contents

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. [4] At 33–41 weeks' gestation, the fetus is able to distinguish its mother's voice from others. [5] [6]

Prenatal pain

Pregnancy timeline Pregnancy timeline.png
Pregnancy timeline

The hypothesis that human fetuses are capable of perceiving pain in the first trimester has little support, although fetuses at 14 weeks may respond to touch. [7] [ additional citation(s) needed ] A multidisciplinary systematic review 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. [8] [9]

In March 2010, the Royal College of Obstetricians and Gynecologists submitted a report, [10] 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", [10] : 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. Fetal pain is not possible before these necessary neural pathways and structures have developed. [10] : 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, which begins to develop in the fetus at week 26. A co-author of that report revisited the evidence in 2020, specifically the functionality of the thalamic projections into the cortical subplate, and posited "an immediate and unreflective pain experience...from as early as 12 weeks." [11]

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. [12]

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 in heart rates and hormone levels in response to invasive procedures are reflexes that do not indicate fetal pain. [8]

Several lines of evidence suggest that a fetus does not awaken during its time in the womb. Much of the literature on fetal pain simply extrapolates from findings and research on premature babies. The presence of such chemicals as adenosine, pregnanolone, and prostaglandin-D2 in both human and animal fetuses, indicate that the fetus is both sedated and anesthetized when in the womb. These chemicals are oxidized with the newborn's first few breaths and washed out of the tissues, increasing consciousness. [13] If the fetus is asleep throughout gestation then the possibility of fetal pain is greatly minimized, [14] [15] although some studies found that the adenosine levels in third-trimester fetuses are only slightly higher than those in adults' blood. [16]

Fetal anesthesia

Direct fetal analgesia is used in only a minority of prenatal surgeries. [17]

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. [8] 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. [18]

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. [19]

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 in April 1997, they deemed the discussion "unhelpful to women and to the scientific debate" [20] 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". [21] 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. [22] Dr. Carlo V. Bellieni also agrees that the anesthesia that women receive for fetal surgery is not sufficient to anesthetize the fetus. [23]

United States legislation

Federal legislation

In 1985, questions about fetal pain were raised during congressional hearings concerning The Silent Scream . [24]

In 2013 during the 113th Congress, Representative Trent Franks introduced a bill called the "Pain-Capable Unborn Child Protection Act" (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. [25]

In 2004 during the 108th Congress, Senator Sam Brownback 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. [26] [27]

State legislation

Subsequently, 25 states have examined similar legislation related to fetal pain and/or fetal anesthesia, [19] and in 2010 Nebraska banned abortions after 20 weeks on the basis of fetal pain. [28] 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 founded by Planned Parenthood, has called "generally irrelevant" and not in line "with the current medical literature". [29] Arthur Caplan, 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." [30]

See also

Related Research Articles

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Intrauterine growth restriction (IUGR), or fetal growth restriction, is the poor growth of a fetus while in the womb during pregnancy. IUGR is defined by clinical features of malnutrition and evidence of reduced growth regardless of an infant's birth weight percentile. The causes of IUGR are broad and may involve maternal, fetal, or placental complications.

<span class="mw-page-title-main">Amniocentesis</span> Sampling of amniotic fluid done mainly to detect fetal chromosomal abnormalities

Amniocentesis is a medical procedure used primarily in the prenatal diagnosis of genetic conditions. It has other uses such as in the assessment of infection and fetal lung maturity. Prenatal diagnostic testing, which includes amniocentesis, is necessary to conclusively diagnose the majority of genetic disorders, with amniocentesis being the gold-standard procedure after 15 weeks' gestation.

<span class="mw-page-title-main">Obstetric ultrasonography</span> Use of medical ultrasonography in pregnancy

Obstetric ultrasonography, or prenatal ultrasound, is the use of medical ultrasonography in pregnancy, in which sound waves are used to create real-time visual images of the developing embryo or fetus in the uterus (womb). The procedure is a standard part of prenatal care in many countries, as it can provide a variety of information about the health of the mother, the timing and progress of the pregnancy, and the health and development of the embryo or fetus.

<span class="mw-page-title-main">Prenatal testing</span> Testing for diseases or conditions in a fetus

Prenatal testing is a tool that can be used to detect some birth defects at various stages prior to birth. Prenatal testing consists of prenatal screening and prenatal diagnosis, which are aspects of prenatal care that focus on detecting problems with the pregnancy as early as possible. These may be anatomic and physiologic problems with the health of the zygote, embryo, or fetus, either before gestation even starts or as early in gestation as practicable. Screening can detect problems such as neural tube defects, chromosome abnormalities, and gene mutations that would lead to genetic disorders and birth defects, such as spina bifida, cleft palate, Down syndrome, trisomy 18, Tay–Sachs disease, sickle cell anemia, thalassemia, cystic fibrosis, muscular dystrophy, and fragile X syndrome. Some tests are designed to discover problems which primarily affect the health of the mother, such as PAPP-A to detect pre-eclampsia or glucose tolerance tests to diagnose gestational diabetes. Screening can also detect anatomical defects such as hydrocephalus, anencephaly, heart defects, and amniotic band syndrome.

Oligohydramnios is a medical condition in pregnancy characterized by a deficiency of amniotic fluid, the fluid that surrounds the fetus in the abdomen, in the amniotic sac. The limiting case is anhydramnios, where there is a complete absence of amniotic fluid. It is typically diagnosed by ultrasound when the amniotic fluid index (AFI) measures less than 5 cm or when the single deepest pocket (SDP) of amniotic fluid measures less than 2 cm. Amniotic fluid is necessary to allow for normal fetal movement, lung development, and cushioning from uterine compression. Low amniotic fluid can be attributed to a maternal, fetal, placental or idiopathic cause and can result in poor fetal outcomes including death. The prognosis of the fetus is dependent on the etiology, gestational age at diagnosis, and the severity of the oligohydramnios.

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<span class="mw-page-title-main">Pregnancy</span> Time of offspring development in mothers body

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Prenatal development involves the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal development until birth.

<span class="mw-page-title-main">Complications of pregnancy</span> Medical condition

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<i>Fetal surgery</i> Growing branch of maternal-fetal medicine

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<i>The Silent Scream</i> 1984 film

The Silent Scream is a 1984 anti-abortion film created and narrated by Bernard Nathanson, a former abortion provider who had become an anti-abortion activist. It was produced by Crusade for Life, Inc., an evangelical anti-abortion organization, and has been described as a pro-life propaganda film. The film depicts the abortion process via ultrasound and shows an abortion taking place in the uterus. During the abortion process, the fetus is described as appearing to make outcries of pain and discomfort. The video has been a popular tool used by the anti-abortion campaign in arguing against abortion, but it has been criticized as misleading by members of the medical community.

A fetus or foetus is the unborn mammalian offspring that develops from an embryo. Following the embryonic stage, the fetal stage of development takes place. Prenatal development is a continuum, with no clear defining feature distinguishing an embryo from a fetus. However, in general a fetus is characterized by the presence of all the major body organs, though they will not yet be fully developed and functional, and some may not yet be situated in their final anatomical location.

Foeticide, or feticide, is the act of killing a fetus, or causing a miscarriage. Definitions differ between legal and medical applications, whereas in law, feticide frequently refers to a criminal offense, in medicine the term generally refers to a part of an abortion procedure in which a provider intentionally induces fetal demise to avoid the chance of an unintended live birth, or as a standalone procedure in the case of selective reduction.

Prenatal memory, also called fetal memory, is important for the development of memory in humans. Many factors can impair fetal memory and its functions, primarily maternal actions. There are multiple techniques available not only to demonstrate the existence of fetal memory but to measure it. Fetal memory is vulnerable to certain diseases so much so that exposure can permanently damage the development of the fetus and even terminate the pregnancy by aborting the fetus. Maternal nutrition and the avoidance of drugs, alcohol and other substances during all nine months of pregnancy is important to the development of the fetus and its memory systems. The use of certain substances can entail long-term permanent effects on the fetus that can carry on throughout their lifespan.

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Early pregnancy bleeding is vaginal bleeding before 14 weeks of gestational age. If the bleeding is significant, hemorrhagic shock may occur. Concern for shock is increased in those who have loss of consciousness, chest pain, shortness of breath, or shoulder pain.

<span class="mw-page-title-main">Fetal EEG</span>

Fetal electroencephalography, also known as prenatal EEG includes any recording of electrical fluctuations arising from the brain of a fetus. Doctors and scientists use EEGs to detect and characterize brain activity, such as sleep states, potential seizures, or levels of a coma. EEG captures the electrical activity in the vicinity of the recording electrodes. The majority of the neural electrical activity arises from the flow of current from the cell bodies of pyramidal neurons to their apical dendrites, which become depolarized by excitatory inputs from other neurons. To record the most accurate signals, scientists try to minimize the distance between the recording electrode and the neural activity that they want to detect. Given the difficulty of attaching electrodes to a fetus inside a uterus, doctors and scientists use a variety of techniques to record fetal brain activity.

References

  1. ↑ Belluck, Pam (2013-09-17). "Complex Science at Issue in Politics of Fetal Pain". The New York Times. ISSN   0362-4331 . Retrieved 2022-09-20.
  2. ↑ Levitan, Dave (2015-05-18). "Does a Fetus Feel Pain at 20 Weeks?". FactCheck.org. Retrieved 2022-09-20.
  3. ↑ Karni, Annie (2022-09-13). "Graham Proposes 15-Week Abortion Ban, Splitting Republicans". The New York Times. ISSN   0362-4331 . Retrieved 2022-09-20.
  4. ↑ Graven, Stanley N.; Browne, Joy V. (December 2008). "Auditory Development in the Fetus and Infant". Newborn and Infant Nursing Reviews. 8 (4): 187–193. doi:10.1053/j.nainr.2008.10.010. ISSN   1527-3369. S2CID   6361226 . Retrieved 31 May 2022.
  5. ↑ Kisilevsky, B.S.; Hains, S.M.J.; Brown, C.A.; Lee, C.T.; Cowperthwaite, B.; Stutzman, S.S.; Swansburg, M.L.; Lee, K.; Xie, X.; Huang, H.; Ye, H.-H.; Zhang, K.; Wang, Z. (2009). "Fetal sensitivity to properties of maternal speech and language". Infant Behavior and Development. 32 (1): 59–71. doi:10.1016/j.infbeh.2008.10.002. PMID   19058856.
  6. ↑ Smith, Laura S.; Dmochowski, Pawel A.; Muir, Darwin W.; Kisilevsky, Barbara S. (2007). "Estimated cardiac vagal tone predicts fetal responses to mother's and stranger's voices". Developmental Psychobiology. 49 (5): 543–7. doi:10.1002/dev.20229. PMID   17577240.
  7. ↑ Marx, Viola; Nagy, Emese (2015-06-08). "Fetal Behavioural Responses to Maternal Voice and Touch". PLOS ONE. 10 (6): e0129118. Bibcode:2015PLoSO..1029118M. doi: 10.1371/journal.pone.0129118 . ISSN   1932-6203. PMC   4460088 . PMID   26053388.
  8. 1 2 3 Lee, Susan J.; Ralston, Henry J. Peter; Drey, Eleanor A.; Partridge, John Colin; Rosen, Mark A. (2005). "Fetal Pain". JAMA. 294 (8): 947–54. doi: 10.1001/jama.294.8.947 . PMID   16118385.
  9. ↑ Derbyshire, S. W G (2006). "Can fetuses feel pain?". BMJ. 332 (7546): 909–12. doi:10.1136/bmj.332.7546.909. PMC   1440624 . PMID   16613970.
  10. 1 2 3 "Fetal Awareness – Review of Research and Recommendations for Practice" (PDF). Royal College of Obstetricians and Gynaecologists. March 2010. Archived from the original (PDF) on 2011-10-02. Retrieved 2019-03-27– via Internet Archive.
  11. ↑ Derbyshire, Stuart WG; Bockmann, John C. (2020-01-01). "Reconsidering fetal pain". Journal of Medical Ethics. 46 (1): 3–6. doi: 10.1136/medethics-2019-105701 . ISSN   0306-6800. PMID   31937669.
  12. ↑ Johnson, Martin and Everitt, Barry. Essential reproduction (Blackwell 2000), p. 235. Retrieved 2007-02-21.
  13. ↑ Lagercrantz, Hugo; Changeux, Jean-Pierre (March 2009). "The Emergence of Human Consciousness: From Fetal to Neonatal Life". Pediatric Research. 65 (3): 255–260. doi: 10.1203/PDR.0b013e3181973b0d . ISSN   0031-3998. PMID   19092726. S2CID   39391626. The delivery from the mother's womb thus causes arousal from a "resting," sleeping, state in utero. After birth, electrophysiological signs on EEG scalp recordings indicate an intense flow of novel sensory stimuli after birth… In addition, arousal is enhanced by the release from endogenous analgesia possibly caused by removal of the mentioned placental "suppressors" which in utero selectively inhibit neural activity of the fetus…. The catecholamine surge triggered by vaginal delivery may also be critical for the arousal at birth.
  14. ↑ Mellor, David J.; Diesch, Tamara J.; Gunn, Alistair J.; Bennet, Laura (2005). "The importance of 'awareness' for understanding fetal pain". Brain Research Reviews. 49 (3): 455–71. doi:10.1016/j.brainresrev.2005.01.006. PMID   16269314. S2CID   9833426.
  15. ↑ Paul, AM (2008-02-10). "The First Ache". The New York Times.
  16. ↑ Bellieni, Carlo Valerio; Buonocore, Giuseppe (2012). "Is fetal pain a real evidence?". The Journal of Maternal-Fetal & Neonatal Medicine . 25 (8): 1203–8. doi:10.3109/14767058.2011.632040. PMID   22023261. S2CID   20578842.
  17. ↑ Bellieni, Carlo V.; Tei, M.; Stazzoni, G.; Bertrando, S.; Cornacchione, S.; Buonocore, G. (2012). "Use of fetal analgesia during prenatal surgery". The Journal of Maternal-Fetal & Neonatal Medicine. 26 (1): 90–5. doi:10.3109/14767058.2012.718392. PMID   22881840. S2CID   46355976.
  18. ↑ Society for Maternal-Fetal Medicine; Society of Family Planning; Norton, Mary E.; Cassidy, Arianna; Ralston, Steven J.; Chatterjee, Debnath; Farmer, Diana; Beasley, Anitra D.; Dragoman, Monica (2022-02-01). "Society for Maternal-Fetal Medicine Consult Series #59: The use of analgesia and anesthesia for maternal-fetal procedures". Contraception. 106: 10–15. doi: 10.1016/j.contraception.2021.10.003 . ISSN   0010-7824. PMID   34740602. S2CID   243477250.
  19. 1 2 Paul, Annie Murphy (February 10, 2008). "The First Ache". New York Times.
  20. ↑ Savage, W.; Wall, P. D; Derbyshire, S. W. (1997). "Do fetuses feel pain?". BMJ. 314 (7088): 1201. doi:10.1136/bmj.314.7088.1201. PMC   2126513 . PMID   9146414.
  21. ↑ McCullagh, P.; Saunders, P J (1997). "Do fetuses feel pain?". BMJ. 314 (7076): 302–3. doi:10.1136/bmj.314.7076.302a. PMC   2125716 . PMID   9022510.
  22. ↑ Devroe, S. (2015). "General anesthesia for caesarean section". Curr Opin Anesthesiol. 28 (3): 240–246. doi:10.1097/ACO.0000000000000185. PMID   25827280. S2CID   38558311.
  23. ↑ Bellieni, Carlo V. (2021-05). "Analgesia for fetal pain during prenatal surgery: 10 years of progress". Pediatric Research89 (7): 1612-1618. ISSN   1530-0447. doi : 10.1038/s41390-020-01170-2.
  24. ↑ Hearing Before the Subcommittee on the Constitution of the Committee on the Judiciary, United States Senate, Ninety-Ninth Congress. (May 21, 1985). First session on: The medical evidence concerning fetal pain. S. Hrg. 99–429; Serial No. J-99-28, pages 10 and following
  25. ↑ Pain-Capable Unborn Child Protection Act of 2013 [ permanent dead link ] H.R.1797, 113th Cong., 1st Sess. (2013)
  26. ↑ Unborn Child Pain Awareness Act of 2005 Archived 2008-10-14 at the Wayback Machine , S.2466, 108t Cong., 2nd Sess. (2004)
  27. ↑ Weisman, Jonathan. "House to Consider Abortion Anesthesia Bill", Washington Post 2006-12-05. Retrieved 2007-02-06.
  28. ↑ Kliff, Sarah Newly Passed 'Fetal Pain' Bill in Nebraska Is a Big Deal The Daily Beast Apr 13, 2010
  29. ↑ Gold Rachel Benson; Nash Elizabeth (2007). "State Abortion Counseling Policies and the Fundamental Principles of Informed Consent". Guttmacher Policy Review. 10 (4).
  30. ↑ Caplan, Arthur. "Abortion politics twist facts in fetal pain laws" MSNBC.com, November 30, 2005
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