Fetal viability: Difference between revisions
These changes address concerns about why there are discrepancies in rates, and also explains that doctors in the German study were not the decision makers of whether to resuscitate infants. It also says there were no differences in birth weight and singleton/multiples status for those resuscitated or not. This gives a thorough response to previous objections to the positive rates. It also addresses concerns on the talk page that previous entries were outdated and too U.S. centric. |
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==Medical viability== |
==Medical viability== |
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[[File:Preterm_infants_survival_rates.svg|thumb|upright=1.4|Preterm infants survival rates based on studies.<ref>{{cite journal | vauthors = Patel RM, Rysavy MA, Bell EF, Tyson JE | title = Survival of Infants Born at Periviable Gestational Ages | journal = Clinics in Perinatology | volume = 44 | issue = 2 | pages = 287–303 | date = June 2017 | pmid = 28477661 | pmc = 5424630 | doi = 10.1016/j.clp.2017.01.009 }}</ref><ref>{{cite journal | |
[[File:Preterm_infants_survival_rates.svg|thumb|upright=1.4|Preterm infants survival rates based on older studies.<ref>{{cite journal | vauthors = Patel RM, Rysavy MA, Bell EF, Tyson JE | title = Survival of Infants Born at Periviable Gestational Ages | journal = Clinics in Perinatology | volume = 44 | issue = 2 | pages = 287–303 | date = June 2017 | pmid = 28477661 | pmc = 5424630 | doi = 10.1016/j.clp.2017.01.009 }}</ref><ref>{{cite journal | vauthors = Costeloe KL, Hennessy EM, Haider S, Stacey F, Marlow N, Draper ES | title = Short term outcomes after extreme preterm birth in England: comparison of two birth cohorts in 1995 and 2006 (the EPICure studies) | journal = BMH | volume = 345 | pages = e7976 | date = December 2012 | pmid = 23212881 | pmc = 3514472 | doi = 10.1136/bmj.e7976 }}</ref><ref>{{cite journal | vauthors = Fellman V, Hellström-Westas L, Norman M, Westgren M, Källén K, Lagercrantz H, Marsál K, Serenius F, Wennergren M | title = One-year survival of extremely preterm infants after active perinatal care in Sweden | journal = JAMA | volume = 301 | issue = 21 | pages = 2225–33 | date = June 2009 | pmid = 19491184 | doi = 10.1001/jama.2009.771 }}</ref><ref>{{cite journal | vauthors = Ancel PY, Goffinet F, Kuhn P, Langer B, Matis J, Hernandorena X, Chabanier P, Joly-Pedespan L, Lecomte B, Vendittelli F, Dreyfus M, Guillois B, Burguet A, Sagot P, Sizun J, Beuchée A, Rouget F, Favreau A, Saliba E, Bednarek N, Morville P, Thiriez G, Marpeau L, Marret S, Kayem G, Durrmeyer X, Granier M, Baud O, Jarreau PH, Mitanchez D, Boileau P, Boulot P, Cambonie G, Daudé H, Bédu A, Mons F, Fresson J, Vieux R, Alberge C, Alberge C, Arnaud C, Vayssière C, Truffert P, Pierrat V, Subtil D, D'Ercole C, Gire C, Simeoni U, Bongain A, Sentilhes L, Rozé JC, Gondry J, Leke A, Deiber M, Claris O, Picaud JC, Ego A, Debillon T, Poulichet A, Coliné E, Favre A, Fléchelles O, Samperiz S, Ramful D, Branger B, Benhammou V, Foix-L'Hélias L, Marchand-Martin L, Kaminski M | display-authors = 6 | title = Survival and morbidity of preterm children born at 22 through 34 weeks' gestation in France in 2011: results of the EPIPAGE-2 cohort study | journal = JAMA Pediatrics | volume = 169 | issue = 3 | pages = 230–8 | date = March 2015 | pmid = 25621457 | doi = 10.1001/jamapediatrics.2014.3351 }}</ref><ref>{{cite journal | vauthors = Boland RA, Davis PG, Dawson JA, Doyle LW | title = Outcomes of infants born at 22-27 weeks' gestation in Victoria according to outborn/inborn birth status | journal = Archives of Disease in Childhood: Fetal and Neonatal Edition | volume = 102 | issue = 2 | pages = F153–F161 | date = March 2017 | pmid = 27531224 | doi = 10.1136/archdischild-2015-310313 }}</ref><ref>{{cite journal | vauthors = Chen F, Bajwa NM, Rimensberger PC, Posfay-Barbe KM, Pfister RE | title = Thirteen-year mortality and morbidity in preterm infants in Switzerland | journal = Archives of Disease in Childhood: Fetal and Neonatal Edition | volume = 101 | issue = 5 | pages = F377-83 | date = September 2016 | pmid = 27059074 | doi = 10.1136/archdischild-2015-308579 }}</ref>]] |
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There is no sharp limit of development, [[gestational age]], or weight at which a human fetus automatically becomes viable.<ref name="developinghuman" /> |
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There is no sharp limit of development, [[gestational age]], or weight at which a human fetus automatically becomes viable.<ref name="developinghuman" /> While there is no sharp limit of development, gestational age, or weight at which a human fetus automatically becomes viable,<ref name=developinghuman>Moore, Keith and Persaud, T. [https://books.google.com/books?id=dbRpAAAAMAAJ&q=%22Prematurity+is+one+of+the+most+common+causes+of+morbidity%22&dq=%22Prematurity+is+one+of+the+most+common+causes+of+morbidity%22&ei=lPzISYHyK4mqMqTGzOwN&pgis=1 ''The Developing Human: Clinically Oriented Embryology''], p. 103 (Saunders 2003).</ref> a 2013 study found that "While only a small proportion of births occur before 24 completed weeks of gestation (about 1 per 1000), survival is rare and most of them are either [[fetal death]]s or live births followed by a neonatal death." <ref>{{cite journal |doi=10.1371/journal.pone.0064869 |pmid=23700489 |pmc=3658983 |title=International Comparisons of Fetal and Neonatal Mortality Rates in High-Income Countries: Should Exclusion Thresholds be Based on Birth Weight or Gestational Age? |journal=PLOS ONE |volume=8 |issue=5 |pages=e64869 |year=2013 |last1=Mohangoo |first1=Ashna D |last2=Blondel |first2=Béatrice |last3=Gissler |first3=Mika |last4=Velebil |first4=Petr |last5=MacFarlane |first5=Alison |last6=Zeitlin |first6=Jennifer |author7=Euro-Peristat Scientific Committee |bibcode=2013PLoSO...864869M }}</ref> According to studies between 2003 and 2005, 20 to 35 percent of babies born at 24 [[weeks of gestation]] survived, while 50 to 70 percent of babies born at 25 weeks, and more than 90 percent born at 26 to 27 weeks, survived.<ref name="MoD">[http://www.marchofdimes.org/loss/neonatal-death.aspx March of Dimes --> Neonatal Death] Retrieved on November 10, 2014. In turn citing: |
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Studies in the last decade have shown an increase in survival rates at 22 and 23 weeks of gestation for those infants born alive. According to a study in Germany, 22-week babies who showed any sign of life after birth (e.g., heartbeat, gasping, movement) who were given active treatment had a 61% survival rate, while 23-week babies had a 71% survival rate.<ref name=":0">{{Cite journal|last=Mehler|first=Katrin|last2=Oberthuer|first2=André|last3=Keller|first3=Titus|last4=Becker|first4=Ingrid|last5=Valter|first5=Markus|last6=Roth|first6=Bernhard|last7=Kribs|first7=Angela|date=2016-07-01|title=Survival Among Infants Born at 22 or 23 Weeks' Gestation Following Active Prenatal and Postnatal Care|journal=JAMA Pediatrics|language=en|volume=170|issue=7|pages=671–677|doi=10.1001/jamapediatrics.2016.0207|pmid=27214875|issn=2168-6203}}</ref> Importantly, physicians did not determine whether or not to give active treatment based on infants' characteristics, but rather left the decision making to parents. For those infants given active care and those given only palliative care, there were no significant differences in birth weight or whether infants were singletons or part of multiples. However, those given palliative care were slightly more immature than the group of infants who were resuscitated (average age: 22 weeks 3 days vs. 22 weeks 4 days).<ref name=":0" /> Study authors note the bundle of interventions used that led to the high survival rate: |
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* Use of prenatal steroids after parental counseling from 22 weeks of gestation |
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* Cesarean delivery with local anesthesia as preferred mode of delivery |
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* Delayed cord clamping |
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* Comfort positioning (lateral) of the infant |
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* Establishment of spontaneous breathing via a stepwise increase in positive end-expiratory pressure |
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* Less invasive surfactant application (LISA)"<ref name=":0" /> |
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This study notes why rates of survival rate may be so low for national studies: "A recent report on ethics in delivery-room care emphasized the impact of self-fulfilling prophecies, meaning that the recommendation not to treat at 22 weeks of gestation inevitably has to lead to low rates of survival. Consequently, reports on big national cohorts in settings where treatment is predominantly withheld for extremely immature infants ''cannot produce valid data on survival"''<ref name=":0" /> [emphasis added]. |
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Similarly, a study in Sweden showed a 58% survival rate for 22-week babies born alive who were given active treatment, and a 66% survival rate for 23-week babies.<ref name=":1">{{Cite journal|last=Norman|first=Mikael|last2=Hallberg|first2=Boubou|last3=Abrahamsson|first3=Thomas|last4=Björklund|first4=Lars J.|last5=Domellöf|first5=Magnus|last6=Farooqi|first6=Aijaz|last7=Foyn Bruun|first7=Cathrine|last8=Gadsbøll|first8=Christian|last9=Hellström-Westas|first9=Lena|last10=Ingemansson|first10=Fredrik|last11=Källén|first11=Karin|date=March 26, 2019|title=Association Between Year of Birth and 1-Year Survival Among Extremely Preterm Infants in Sweden During 2004-2007 and 2014-2016|journal=JAMA|volume=321|issue=12|pages=1188–1199|doi=10.1001/jama.2019.2021|issn=1538-3598|pmc=6439685|pmid=30912837}}</ref> A data review in the United Kingdom showed a 54% survival rate for 22-week babies given intensive care.<ref name=":2">{{Cite web|url=https://www.bapm.org/posts/109-new-bapm-framework-on-extreme-preterm-birth-published|title=New BAPM Framework on Extreme Preterm Birth Published {{!}} British Association of Perinatal Medicine|website=www.bapm.org|access-date=2020-02-19}}</ref> However, the authors note that the survival rates of infants may be overly positive as "there is the possibility of selection bias and survivors may represent a sub-group of 22 week gestation babies with more favourable risk factors".<ref name=":2" /> A U.S. study showed a 39% survival rate for those given active treatment at 22 weeks and a 55% survival rate for those given active treatment when born at 23 weeks (mothers were given antenatal steroids for both age groups).<ref>{{Cite journal|last=Ehret|first=Danielle E. Y.|last2=Edwards|first2=Erika M.|last3=Greenberg|first3=Lucy T.|last4=Bernstein|first4=Ira M.|last5=Buzas|first5=Jeffrey S.|last6=Soll|first6=Roger F.|last7=Horbar|first7=Jeffrey D.|date=2018-10-05|title=Association of Antenatal Steroid Exposure With Survival Among Infants Receiving Postnatal Life Support at 22 to 25 Weeks' Gestation|journal=JAMA Network Open|language=en|volume=1|issue=6|pages=e183235|doi=10.1001/jamanetworkopen.2018.3235|pmid=30646235|pmc=6324435}}</ref> "I've been in this business for 40 years, and I've seen the threshold of viability move back about one week every 10 years or so in my practice," reports Edward Bell, a neonatologist at the University of Iowa Children's Hospital.<ref>{{Cite web|url=https://medicalxpress.com/news/2019-03-sweden-world-extremely-preterm-babies.html|title=New studies confirm improved survival of extremely preterm babies|website=medicalxpress.com|language=en-us|access-date=2020-03-02}}</ref> |
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Unfortunately, many babies in this age group are stillborn, meaning they are showing any signs of life when they are delivered; however, this percentage has been decreasing as antenatal treatment has improved. The aforementioned study in Sweden reported that between 2014-2016, 35% of 22-week infants were stillborn, and 29% of 23-week infants were stillborn.<ref name=":1" /> |
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Older data have been less optimistic. According to studies between 2003 and 2005, 20 to 35 percent of babies born at 24 [[weeks of gestation]] survived, while 50 to 70 percent of babies born at 25 weeks, and more than 90 percent born at 26 to 27 weeks, survived.<ref name="MoD">[http://www.marchofdimes.org/loss/neonatal-death.aspx March of Dimes --> Neonatal Death] Retrieved on November 10, 2014. In turn citing: |
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⚫ | *{{cite journal | vauthors = Tyson JE, Parikh NA, Langer J, Green C, Higgins RD | title = Intensive care for extreme prematurity--moving beyond gestational age | journal = The New England Journal of Medicine | volume = 358 | issue = 16 | pages = 1672–81 | date = April 2008 | pmid = 18420500 | pmc = 2597069 | doi = 10.1056/NEJMoa073059 }} |
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⚫ | *{{cite journal | vauthors = Luke B, Brown MB | title = The changing risk of infant mortality by gestation, plurality, and race: 1989-1991 versus 1999-2001 | journal = Pediatrics | volume = 118 | issue = 6 | pages = 2488–97 | date = December 2006 | pmid = 17142535 | pmc = 3623686 | doi = 10.1542/peds.2006-1824 }} |
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⚫ | *{{cite journal | author = The American College of Obstetricians and Gynecologists | title = ACOG Practice Bulletin: Clinical Management Guidelines for Obstetrcian-Gynecologists: Number 38, September 2002. Perinatal care at the threshold of viability | journal = Obstetrics and Gynecology | volume = 100 | issue = 3 | pages = 617–24 | date = September 2002 | pmid = 12220792 | doi = 10.1016/S0029-7844(02)02260-3 }}</ref> |
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[[File:Prenatal development table.svg|thumb|center|800px|Stages in [[prenatal development]], showing ''viability'' and point of 50% chance of survival (''limit of viability'') at bottom. Weeks and months numbered [[gestational age|by gestation]].]] |
[[File:Prenatal development table.svg|thumb|center|800px|Stages in [[prenatal development]], showing ''viability'' and point of 50% chance of survival (''limit of viability'') at bottom. Weeks and months numbered [[gestational age|by gestation]].]] |
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! Completed weeks of gestation at birth |
! Completed weeks of gestation at birth |
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| 22 || 23 || 24 || 25 || 26 |
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! Probability of survival if showing any sign of life at birth and given intensive care (based on individual studies) |
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! Chance of survival<ref name="spensershope.org"/> |
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| Up to 61%<ref name=":0" />|| Up to 71%<ref name=":0" />|| 79%<ref name=":1" />|| 88%<ref name=":1" />|| 92%<ref name=":1" /> |
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==Period of viability== |
==Period of viability== |
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Beliefs about viability vary by country. |
Beliefs about viability vary by country. One study showed that in Sweden, neonatologists generally consider whether or not to give medical treatment to babies born at 22 weeks, whereas neonatologists in the Netherlands generally do not consider treating babies until 24 weeks gestation.<ref>{{Cite journal|last=Wilkinson|first=Dominic|last2=Verhagen|first2=Eduard|last3=Johansson|first3=Stefan|date=September 2018|title=Thresholds for Resuscitation of Extremely Preterm Infants in the UK, Sweden, and Netherlands|journal=Pediatrics|volume=142|issue=Suppl 1|pages=S574–S584|doi=10.1542/peds.2018-0478I|issn=1098-4275|pmc=6379058|pmid=30171144}}</ref> In 2019, the British Association of Perinatal Medicine recommended that physicians in the United Kingdom consider whether or not to treat babies born at 22 weeks, revising its previous recommendation of 24 weeks.<ref>{{Cite web|url=https://www.bapm.org/resources/80-perinatal-management-of-extreme-preterm-birth-before-27-weeks-of-gestation-2019|title=Perinatal Management of Extreme Preterm Birth Before 27 weeks of Gestation (2019) {{!}} British Association of Perinatal Medicine|website=www.bapm.org|access-date=2020-02-21}}</ref> Whether the fetus is in the period of viability has legal ramifications as far as the fetus' rights of protection are concerned.<ref>{{cite web | title = Attorney Catherine Christophillis Discusses The Reasoning Behind The Drug Testing Of Pregnant Women | date = October 25, 2000 | work = Legal News Chat Transcript | url = http://news.findlaw.com/transcripts/s/christophillis20001025.html }}</ref> Traditionally, the period of viability referred to the period after the twenty-eighth week,<ref>{{cite book|last=Finney|first=Patrick A.|url=https://archive.org/details/MoralProblemsInHospitalPractice|title=''Moral Problems in Hospital Practice: a Practical Handbook.|date=1922|publisher=Herder Bk. Co|location=St. Louis|page=[https://archive.org/details/MoralProblemsInHospitalPractice/page/n42 24]|oclc=14054441}}</ref> |
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One 2018 study showed that there was a significant difference between countries in what was considered to be the "grey zone": the "grey zone" was considered to be 22.0 - 22.6/23 weeks in Sweden, 23.0 – 23.6/24 weeks in the UK, and 24.0-25.6/26 weeks in Netherlands.<ref name=pmid30171144/> Whether the fetus is in the period of viability may have legal ramifications as far as the fetus' rights of protection are concerned.<ref>{{cite web | title = Attorney Catherine Christophillis Discusses The Reasoning Behind The Drug Testing Of Pregnant Women | date = October 25, 2000 | work = Legal News Chat Transcript | url = http://news.findlaw.com/transcripts/s/christophillis20001025.html }}</ref> Traditionally, the period of viability referred to the period after the twenty-eighth week,<ref>{{cite book|last=Finney|first=Patrick A.|url=https://archive.org/details/MoralProblemsInHospitalPractice|title=''Moral Problems in Hospital Practice: a Practical Handbook.|date=1922|publisher=Herder Bk. Co|location=St. Louis|page=[https://archive.org/details/MoralProblemsInHospitalPractice/page/n42 24]|oclc=14054441}}</ref> |
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Viability can incorporate weight as well as gestational age.<ref name=AIHW-2012>{{cite web| vauthors = Li Z, Zeki R, Hilder L, Sullivan, EA |title=Australia's Mothers and Babies 2010 |url= http://www.aihw.gov.au/WorkArea/DownloadAsset.aspx?id=60129542372 |work=Perinatal statistics series no. 27. Cat. no. PER 57|publisher=Australian Institute of Health and Welfare National Perinatal Statistics Unit, Australian Government|access-date=4 July 2013 |year=2012}}</ref><ref name=Mohangoo-2013>{{cite journal | vauthors = Mohangoo AD, Blondel B, Gissler M, Velebil P, Macfarlane A, Zeitlin J | title = International comparisons of fetal and neonatal mortality rates in high-income countries: should exclusion thresholds be based on birth weight or gestational age? | journal = PLOS ONE | volume = 8 | issue = 5 | pages = e64869 | year = 2013 | pmid = 23700489 | pmc = 3658983 | doi = 10.1371/journal.pone.0064869 | editor1-last = Wright | bibcode = 2013PLoSO...864869M | editor1-first = Linda }}</ref><ref name=RCOG-late-abortion>{{cite web|author1=Royal College of Obstetricians |author2=Gynaecologists UK |title=Further Issues Relating to Late Abortion, Fetal Viability and Registration of Births and Deaths |url=http://www.rcog.org.uk/womens-health/clinical-guidance/further-issues-relating-late-abortion-fetal-viability-and-registrati |publisher=Royal College of Obstetricians and Gynaecologists UK |access-date=4 July 2013 |date=April 2001 |url-status=dead |archive-url=https://web.archive.org/web/20131105042348/http://www.rcog.org.uk/womens-health/clinical-guidance/further-issues-relating-late-abortion-fetal-viability-and-registrati |archive-date=5 November 2013 }}</ref> |
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===United States Supreme Court=== |
===United States Supreme Court=== |
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===Born-Alive Infants Protection Act of 2002=== |
===Born-Alive Infants Protection Act of 2002=== |
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In 2002, the U.S. Government enacted the [[Born-Alive Infants Protection Act]]. Whereas a fetus may be ''viable'' or not ''viable'' in utero, this law provides a legal definition for personal human life when not in utero. It defines "born alive" as "the complete expulsion or extraction from his or her mother of that member, at any stage of development, who after such expulsion or extraction breathes or has a beating heart, pulsation of the umbilical cord, or definite movement of voluntary muscles"<ref>{{cite web|url=http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=107_cong_reports&docid=f:hr186.107|title=House Report 107-186 - BORN-ALIVE INFANTS PROTECTION ACT OF 2001 |website=frwebgate.access.gpo.gov|access-date=3 April 2018}}</ref> and specifies that any of these is the action of a living human person. While the implications of this law for defining viability in medicine may not be fully explored,<ref name=Sayeed>{{cite journal | vauthors = Sayeed SA | title = Baby doe redux? The Department of Health and Human Services and the Born-Alive Infants Protection Act of 2002: a cautionary note on normative neonatal practice | journal = Pediatrics | volume = 116 | issue = 4 | pages = e576-85 | date = October 2005 | pmid = 16199687 | doi = 10.1542/peds.2005-1590 }}</ref> in practice doctors and nurses are advised not to resuscitate such persons with gestational age of 22 weeks or less, under 400 g weight, with anencephaly, or with a confirmed diagnosis of trisomy 13 or 18.<ref name=Dilemma_Verge>{{cite journal|last1=Powell|first1=Traci | name-list-format = vanc |title=Decisions and Dilemmas Related to Resuscitation of Infants Born on the Verge of Viability|journal=NAINR|date=2012|volume=12|issue=1|pages=27–32|url=http://www.medscape.com/viewarticle/760750_6|access-date=8 October 2015|doi=10.1053/j.nainr.2011.12.004}}</ref><ref name=AHA_Resuscitate>{{cite journal | vauthors = Kattwinkel J, Perlman JM, Aziz K, Colby C, Fairchild K, Gallagher J, Hazinski MF, Halamek LP, Kumar P, Little G, McGowan JE, Nightengale B, Ramirez MM, Ringer S, Simon WM, Weiner GM, Wyckoff M, Zaichkin J | title = Neonatal resuscitation: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care | journal = Pediatrics | volume = 126 | issue = 5 | pages = e1400-13 | date = November 2010 | pmid = 20956432 | doi = 10.1542/peds.2010-2972E }}</ref> |
In 2002, the U.S. Government enacted the [[Born-Alive Infants Protection Act]]. Whereas a fetus may be ''viable'' or not ''viable'' in utero, this law provides a legal definition for personal human life when not in utero. It defines "born alive" as "the complete expulsion or extraction from his or her mother of that member, at any stage of development, who after such expulsion or extraction breathes or has a beating heart, pulsation of the umbilical cord, or definite movement of voluntary muscles"<ref>{{cite web|url=http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=107_cong_reports&docid=f:hr186.107|title=House Report 107-186 - BORN-ALIVE INFANTS PROTECTION ACT OF 2001 |website=frwebgate.access.gpo.gov|access-date=3 April 2018}}</ref> and specifies that any of these is the action of a living human person. While the implications of this law for defining viability in medicine may not be fully explored,<ref name=Sayeed>{{cite journal | vauthors = Sayeed SA | title = Baby doe redux? The Department of Health and Human Services and the Born-Alive Infants Protection Act of 2002: a cautionary note on normative neonatal practice | journal = Pediatrics | volume = 116 | issue = 4 | pages = e576-85 | date = October 2005 | pmid = 16199687 | doi = 10.1542/peds.2005-1590 }}</ref> in practice doctors and nurses are advised not to resuscitate such persons with gestational age of 22 weeks or less, under 400 g weight, with anencephaly, or with a confirmed diagnosis of trisomy 13 or 18.<ref name=Dilemma_Verge>{{cite journal|last1=Powell|first1=Traci | name-list-format = vanc |title=Decisions and Dilemmas Related to Resuscitation of Infants Born on the Verge of Viability|journal=NAINR|date=2012|volume=12|issue=1|pages=27–32|url=http://www.medscape.com/viewarticle/760750_6|access-date=8 October 2015|doi=10.1053/j.nainr.2011.12.004}}</ref><ref name=AHA_Resuscitate>{{cite journal | vauthors = Kattwinkel J, Perlman JM, Aziz K, Colby C, Fairchild K, Gallagher J, Hazinski MF, Halamek LP, Kumar P, Little G, McGowan JE, Nightengale B, Ramirez MM, Ringer S, Simon WM, Weiner GM, Wyckoff M, Zaichkin J | title = Neonatal resuscitation: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care | journal = Pediatrics | volume = 126 | issue = 5 | pages = e1400-13 | date = November 2010 | pmid = 20956432 | doi = 10.1542/peds.2010-2972E | url = http://pediatrics.aappublications.org/content/126/5/e1400.full }}</ref> |
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===U.S. state laws=== |
===U.S. state laws=== |
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Forty-three states have laws restricting post-viability abortions. Some allow doctors to decide for themselves if the fetus is viable. Some require doctors to perform tests to prove a fetus is pre-viable and require multiple doctors to certify the findings. The procedure [[intact dilation and extraction]] (IDX) became a focal point in the abortion debate,<ref> |
Forty-three states have laws restricting post-viability abortions. Some allow doctors to decide for themselves if the fetus is viable. Some require doctors to perform tests to prove a fetus is pre-viable and require multiple doctors to certify the findings. The procedure [[intact dilation and extraction]] (IDX) became a focal point in the abortion debate,<ref>Guttmacher.org [http://www.guttmacher.org/pubs/journals/3500603.html Abortion Incidence and Services in the United States in 2000]</ref> based on the belief that it is used mainly post-viability.<ref>Franklin Foer (1997). Fetal Viability. [ONLINE] Available at: http://www.slate.com/articles/news_and_politics/the_gist/1997/05/fetal_viability.html. [Last Accessed 14 November 2012].</ref> IDX was made illegal in most circumstances by the [[Partial-Birth Abortion Ban Act]] in 2003, which the U.S. Supreme Court upheld in the case of ''[[Gonzales v. Carhart]]''. |
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==Limit of viability== |
==Limit of viability== |
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The '''limit of viability''' is the [[gestational age]] at which a [[premature birth|prematurely born]] [[fetus]]/[[infant]] has a 50% chance of long-term survival outside its mother's womb. With the support of [[neonatal intensive care unit]]s, the limit of viability in the developed world has declined since 50 years ago.<ref name="pmid28883097">{{cite journal | vauthors = Santhakumaran S, Statnikov Y, Gray D, Battersby C, Ashby D, Modi N | title = Survival of very preterm infants admitted to neonatal care in England 2008-2014: time trends and regional variation | journal = Archives of Disease in Childhood: Fetal and Neonatal Edition | volume = 103 | issue = 3 | pages = F208–F215 | date = May 2018 | pmid = 28883097 | pmc = 5916099 | doi = 10.1136/archdischild-2017-312748 }}</ref><ref>{{cite news | first = Fergus | last = Walsh | name-list-format = vanc |title=Prem baby survival rates revealed |url=http://news.bbc.co.uk/1/hi/health/7340288.stm |date=11 April 2008 |publisher=BBC News |access-date=2008-05-11}}</ref> |
The '''limit of viability''' is the [[gestational age]] at which a [[premature birth|prematurely born]] [[fetus]]/[[infant]] has a 50% chance of long-term survival outside its mother's womb. With the support of [[neonatal intensive care unit]]s, the limit of viability in the developed world has declined since 50 years ago.<ref name="pmid28883097">{{cite journal | vauthors = Santhakumaran S, Statnikov Y, Gray D, Battersby C, Ashby D, Modi N | title = Survival of very preterm infants admitted to neonatal care in England 2008-2014: time trends and regional variation | journal = Archives of Disease in Childhood: Fetal and Neonatal Edition | volume = 103 | issue = 3 | pages = F208–F215 | date = May 2018 | pmid = 28883097 | pmc = 5916099 | doi = 10.1136/archdischild-2017-312748 }}</ref><ref>{{cite news | first = Fergus | last = Walsh | name-list-format = vanc |title=Prem baby survival rates revealed |url=http://news.bbc.co.uk/1/hi/health/7340288.stm |date=11 April 2008 |publisher=BBC News |access-date=2008-05-11}}</ref> |
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⚫ | Different jurisdictions have different policies regarding the resuscitation of extremely premature newborns, that may be based on various factors such as gestational age, weight and medical presentation of the baby, the desires of parents and medical practitioners. The risk of severe disability of very premature babies or of mortality despite medical efforts lead to ethical debates over [[quality of life]] and [[futile medical care]], but also about the sanctity of life as viewed in various religious doctrines.<ref>http://nuffieldbioethics.org/wp-content/uploads/2014/07/CCD-Short-Version-FINAL.pdf</ref> A majority will not have any severe disabilities; the British Association of Perinatal Medicine reports that 2/3 of 22-week babies will not have a severe disability, and 3/4 of 23-week babies will not have a severe disability; the British Association of Perinatal Medicine notes "disability is generally impossible to predict for an individual baby at birth".<ref name=":2" /> |
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Currently, the limit of viability is considered to be around 24 weeks, although the incidence of major disabilities remains high at this point.<ref name=pmid16396856>{{cite journal | vauthors = Kaempf JW, Tomlinson M, Arduza C, Anderson S, Campbell B, Ferguson LA, Zabari M, Stewart VT | title = Medical staff guidelines for periviability pregnancy counseling and medical treatment of extremely premature infants | journal = Pediatrics | volume = 117 | issue = 1 | pages = 22–9 | date = January 2006 | pmid = 16396856 | doi = 10.1542/peds.2004-2547 }}</ref><ref name="pmid18240080">{{cite journal | vauthors = Morgan MA, Goldenberg RL, Schulkin J | title = Obstetrician-gynecologists' practices regarding preterm birth at the limit of viability | journal = The Journal of Maternal-Fetal & Neonatal Medicine | volume = 21 | issue = 2 | pages = 115–21 | date = February 2008 | pmid = 18240080 | doi = 10.1080/14767050701866971 }}</ref> Neo-natologists generally would not provide intensive care at 23 weeks, but would from 26 weeks.<ref name="pmid17955714">{{cite journal | vauthors = Vavasseur C, Foran A, Murphy JF | title = Consensus statements on the borderlands of neonatal viability: from uncertainty to grey areas | journal = Irish Medical Journal | volume = 100 | issue = 8 | pages = 561–4 | date = September 2007 | pmid = 17955714 | doi = | quote = All would provide intensive care at 26 weeks and most would not at 23 weeks. The grey area is 24 and 25 weeks gestation. This group of infants constitute 2 per 1000 births. }}</ref><ref name=pmid16396856/><ref>''Roe v. Wade'', [http://caselaw.lp.findlaw.com/scripts/getcase.pl?navby=CASE&court=US&vol=410&page=113 410 U.S. 113] (1973) ("viability is usually placed at about seven months (28 weeks) but may occur earlier, even at 24 weeks.") Retrieved 2007-03-04.</ref> |
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⚫ | Different jurisdictions have different policies regarding the resuscitation of extremely premature newborns, that may be based on various factors such as gestational age, weight and medical presentation of the baby, the desires of parents and medical practitioners. The |
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{{As of|2006}}, the [[Premature birth#Notable preterm births|two youngest children]] to survive premature birth are thought to be [[James Elgin Gill]] (born on 20 May 1987 in [[Ottawa|Ottawa, Ontario]], Canada, at 21 weeks and 5 days gestational age),<ref name="titlePowell's Books - Guinness World Records 2004 (Guinness Book of Records) by">{{cite web |url=http://www.powells.com/biblio?show=0553587129&page=excerpt? |title=Powell's Books - Guinness World Records 2004 (Guinness Book of Records) by |access-date=2007-11-28 |format= |website=}}</ref><ref name="titleMiracle child">{{cite web |url=http://www.canada.com/topics/bodyandhealth/story.html?id=db8f33ab-33e9-429f-bedc-b6ca80f61bdc |title=Miracle child |access-date=2007-11-28 |url-status=dead |archive-url=https://web.archive.org/web/20071209065838/http://www.canada.com/topics/bodyandhealth/story.html?id=db8f33ab-33e9-429f-bedc-b6ca80f61bdc |archive-date=2007-12-09 }}</ref> and Amillia Taylor (an IVF pregnancy, born on 24 October 2006 in [[Miami]], [[Florida]], at 21 weeks and 6 days gestational age).<ref name="bbcAmillia"> |
{{As of|2006}}, the [[Premature birth#Notable preterm births|two youngest children]] to survive premature birth are thought to be [[James Elgin Gill]] (born on 20 May 1987 in [[Ottawa|Ottawa, Ontario]], Canada, at 21 weeks and 5 days gestational age),<ref name="titlePowell's Books - Guinness World Records 2004 (Guinness Book of Records) by">{{cite web |url=http://www.powells.com/biblio?show=0553587129&page=excerpt? |title=Powell's Books - Guinness World Records 2004 (Guinness Book of Records) by |access-date=2007-11-28 |format= |website=}}</ref><ref name="titleMiracle child">{{cite web |url=http://www.canada.com/topics/bodyandhealth/story.html?id=db8f33ab-33e9-429f-bedc-b6ca80f61bdc |title=Miracle child |access-date=2007-11-28 |url-status=dead |archive-url=https://web.archive.org/web/20071209065838/http://www.canada.com/topics/bodyandhealth/story.html?id=db8f33ab-33e9-429f-bedc-b6ca80f61bdc |archive-date=2007-12-09 }}</ref> and Amillia Taylor (an IVF pregnancy, born on 24 October 2006 in [[Miami]], [[Florida]], at 21 weeks and 6 days gestational age).<ref name="bbcAmillia"> |
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{{cite news | url = http://news.bbc.co.uk/1/hi/world/americas/6384621.stm | title = Most-premature baby allowed home | publisher = [[BBC News]] | date = 2007-02-21 | access-date=2007-05-05}}</ref><ref>Baptist Hospital of Miami, [http://www.baptisthealth.net/vgn/images/portal/cit_449/59/45/73662064factsheetTaylorbaby.pdf Fact Sheet] {{webarchive|url=https://web.archive.org/web/20090326092358/http://www.baptisthealth.net/vgn/images/portal/cit_449/59/45/73662064factsheetTaylorbaby.pdf |date=2009-03-26 }} (2006).</ref> Both children were born just under 20 weeks from fertilization (or 22 weeks' gestation). At birth, Taylor was {{convert|9|in|cm|2}} long and weighed 10 ounces (283 grams).<ref name="bbcAmillia"/> She suffered [[digestion|digestive]] and [[Respiratory system|respiratory]] problems, together with a [[brain]] [[bleeding|hemorrhage]]. She was discharged from the Baptist Children's Hospital on 20 February 2007.<ref name="bbcAmillia"/> As of 2013, Taylor was in kindergarten and at the small end of the normal [[growth curve (biology)|growth curve]] with some developmental delays.<ref>{{cite news |url=https://edmontonjournal.com/health/politicians+debate+science+revealing+more+about+what+happens/8170349/story.html |title=Fate of the fetus: As politicians debate, science reveals more and more about what happens during pregnancy |first=Sharon |last=Kirkey |publisher=Postmedia News |date=29 March 2013 |access-date=5 June 2013}}</ref> |
{{cite news | url = http://news.bbc.co.uk/1/hi/world/americas/6384621.stm | title = Most-premature baby allowed home | publisher = [[BBC News]] | date = 2007-02-21 | access-date=2007-05-05}}</ref><ref>Baptist Hospital of Miami, [http://www.baptisthealth.net/vgn/images/portal/cit_449/59/45/73662064factsheetTaylorbaby.pdf Fact Sheet] {{webarchive|url=https://web.archive.org/web/20090326092358/http://www.baptisthealth.net/vgn/images/portal/cit_449/59/45/73662064factsheetTaylorbaby.pdf |date=2009-03-26 }} (2006).</ref> Both children were born just under 20 weeks from fertilization (or 22 weeks' gestation). At birth, Taylor was {{convert|9|in|cm|2}} long and weighed 10 ounces (283 grams).<ref name="bbcAmillia"/> She suffered [[digestion|digestive]] and [[Respiratory system|respiratory]] problems, together with a [[brain]] [[bleeding|hemorrhage]]. She was discharged from the Baptist Children's Hospital on 20 February 2007.<ref name="bbcAmillia"/> As of 2013, Taylor was in kindergarten and at the small end of the normal [[growth curve (biology)|growth curve]] with some developmental delays.<ref>{{cite news |url=https://edmontonjournal.com/health/politicians+debate+science+revealing+more+about+what+happens/8170349/story.html |title=Fate of the fetus: As politicians debate, science reveals more and more about what happens during pregnancy |first=Sharon |last=Kirkey |publisher=Postmedia News |date=29 March 2013 |access-date=5 June 2013}}</ref> |
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<!---<ref>Halamek, Louis. "[http://neoreviews.aappublications.org/cgi/content/extract/4/6/e153 Prenatal Consultation at the Limits of Viability]", ''NeoReviews'', Vol.4 No.6 (2003): "most neonatologists would agree that survival of infants younger than approximately 22 to 23 weeks’ estimated gestational age [i.e. 20 to 21 weeks' estimated fertilization age] is universally dismal and that resuscitative efforts should not be undertaken when a neonate is born at this point in pregnancy."</ref>---> |
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<!---<ref>{{cite journal |last1=Halamek |first1=L. P. |title=Prenatal Consultation at the Limits of Viability |journal=NeoReviews |date=1 June 2003 |volume=4 |issue=6 |pages=153e–156 |doi=10.1542/neo.4-6-e153 }}</ref>---> |
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A [[preterm birth]], also known as ''premature birth'', is defined as babies born alive before 37 weeks of pregnancy are completed.<ref name="who.int">{{cite web|url=http://www.who.int/mediacentre/factsheets/fs363/en/|title=Preterm birth |website=World Health Organization|access-date=3 April 2018}}</ref> |
A [[preterm birth]], also known as ''premature birth'', is defined as babies born alive before 37 weeks of pregnancy are completed.<ref name="who.int">{{cite web|url=http://www.who.int/mediacentre/factsheets/fs363/en/|title=Preterm birth |website=World Health Organization|access-date=3 April 2018}}</ref> |
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[[Premature rupture of membranes|Rupture of the fetal membranes]] before 24 weeks of gestation with loss of amniotic fluid markedly decreases the baby's chances of survival, even if the baby is delivered much later.<ref name="spensershope.org">(). What are the chances that my baby will survive?. [ONLINE] Available at: http://www.spensershope.org/chances_for_survival.htm {{Webarchive|url=https://web.archive.org/web/20180809230110/http://www.spensershope.org/chances_for_survival.htm|date=2018-08-09}}. [Last Accessed 14 November 2012].</ref> |
[[Premature rupture of membranes|Rupture of the fetal membranes]] before 24 weeks of gestation with loss of amniotic fluid markedly decreases the baby's chances of survival, even if the baby is delivered much later.<ref name="spensershope.org">(). What are the chances that my baby will survive?. [ONLINE] Available at: http://www.spensershope.org/chances_for_survival.htm {{Webarchive|url=https://web.archive.org/web/20180809230110/http://www.spensershope.org/chances_for_survival.htm|date=2018-08-09}}. [Last Accessed 14 November 2012].</ref> |
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The quality of the facility—whether the hospital offers neonatal critical care services, whether it is a Level I pediatric trauma care facility, the availability of corticosteroids and other medications at the facility, the experience and number of physicians and nurses in neonatology and obstetrics and of the providers has a limited but still significant impact on fetal viability. Facilities that have obstetrical services and emergency rooms and operating facilities, even if smaller, can be used in areas where higher services are not available to stabilize the mother and fetus or neonate until they can be transferred to an appropriate facility.<ref>{{cite |
The quality of the facility—whether the hospital offers neonatal critical care services, whether it is a Level I pediatric trauma care facility, the availability of corticosteroids and other medications at the facility, the experience and number of physicians and nurses in neonatology and obstetrics and of the providers has a limited but still significant impact on fetal viability. Facilities that have obstetrical services and emergency rooms and operating facilities, even if smaller, can be used in areas where higher services are not available to stabilize the mother and fetus or neonate until they can be transferred to an appropriate facility.<ref>{{cite web|url=https://www.nih.gov/news-events/news-releases/nih-study-reveals-factors-influence-premature-infant-survival-disability|title=NIH Study Reveals Factors That Influence Premature Infant Survival, Disability|date=13 September 2015|website=nih.gov|access-date=3 April 2018}}</ref><ref name="ReferenceA">{{cite journal|vauthors=Glass HC, Costarino AT, Stayer SA, Brett CM, Cladis F, Davis PJ|date=June 2015|title=Outcomes for extremely premature infants|journal=Anesthesia and Analgesia|volume=120|issue=6|pages=1337–51|doi=10.1213/ANE.0000000000000705|pmc=4438860|pmid=25988638}}</ref><ref>{{cite web|url=https://www.ncbi.nlm.nih.gov/books/NBK11385/|title=Mortality and Acute Complications in Preterm Infants|first1=Richard E.|last1=Behrman|first2=Adrienne Stith|last2=Butler | name-list-format = vanc | collaboration = Institute of Medicine (US) Committee on Understanding Premature Birth and Assuring Healthy|last3=Outcomes|date=3 April 2018|publisher=National Academies Press (US)|access-date=3 April 2018 }}</ref><ref>{{cite news|url=https://www.nytimes.com/2015/05/07/health/premature-babies-22-weeks-viability-study.html|title=Premature Babies May Survive at 22 Weeks if Treated, Study Finds|first=Pam|last=Belluck|date=6 May 2015|access-date=3 April 2018|newspaper=The New York Times}}</ref> |
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== See also == |
== See also == |
Revision as of 15:59, 9 March 2020
Fetal viability or foetal viability is the ability of a fetus to survive outside the uterus.[1]
Definitions
Viability, as the word has been used in United States constitutional law since Roe v. Wade, is the potential of the fetus to survive outside the uterus after birth, natural or induced, when supported by up-to-date medicine. Fetal viability depends largely on the fetal organ maturity, and environmental conditions.[2] According to Websters Encyclopedic Unabridged Dictionary of the English Language, viability of a fetus means having reached such a stage of development as to be capable of living, under normal conditions, outside the uterus. Viability exists as a function of biomedical and technological capacities, which are different in different parts of the world. As a consequence, there is, at the present time, no worldwide, uniform gestational age that defines viability.[3]
According to the McGraw-Hill medical dictionary a nonviable fetus is "an expelled or delivered fetus which, although living, cannot possibly survive to the point of sustaining life independently, even with support of the best available medical therapy."[4] A legal definition states: "Nonviable means not capable of living, growing, or developing and functioning successfully. It is antithesis of viable, which is defined as having attained such form and development of organs as to be normally capable of living outside the uterus." [Wolfe v. Isbell, 291 Ala. 327, 329 (Ala. 1973)][5]
Various jurisdictions have different legal definitions of viability. In Ireland, under the Health (Regulation of Termination of Pregnancy) Act 2018, fetal viability is defined as "the point in a pregnancy at which, in the reasonable opinion of a medical practitioner, the foetus is capable of survival outside the uterus without extraordinary life-sustaining measures." [Definitions (Part 2)(8)][6]
Medical viability
![](http://upload.wikimedia.org/wikipedia/commons/thumb/a/a0/Preterm_infants_survival_rates.svg/310px-Preterm_infants_survival_rates.svg.png)
There is no sharp limit of development, gestational age, or weight at which a human fetus automatically becomes viable.[1]
Studies in the last decade have shown an increase in survival rates at 22 and 23 weeks of gestation for those infants born alive. According to a study in Germany, 22-week babies who showed any sign of life after birth (e.g., heartbeat, gasping, movement) who were given active treatment had a 61% survival rate, while 23-week babies had a 71% survival rate.[13] Importantly, physicians did not determine whether or not to give active treatment based on infants' characteristics, but rather left the decision making to parents. For those infants given active care and those given only palliative care, there were no significant differences in birth weight or whether infants were singletons or part of multiples. However, those given palliative care were slightly more immature than the group of infants who were resuscitated (average age: 22 weeks 3 days vs. 22 weeks 4 days).[13] Study authors note the bundle of interventions used that led to the high survival rate:
- Use of prenatal steroids after parental counseling from 22 weeks of gestation
- Cesarean delivery with local anesthesia as preferred mode of delivery
- Delayed cord clamping
- Comfort positioning (lateral) of the infant
- Establishment of spontaneous breathing via a stepwise increase in positive end-expiratory pressure
- Less invasive surfactant application (LISA)"[13]
This study notes why rates of survival rate may be so low for national studies: "A recent report on ethics in delivery-room care emphasized the impact of self-fulfilling prophecies, meaning that the recommendation not to treat at 22 weeks of gestation inevitably has to lead to low rates of survival. Consequently, reports on big national cohorts in settings where treatment is predominantly withheld for extremely immature infants cannot produce valid data on survival"[13] [emphasis added].
Similarly, a study in Sweden showed a 58% survival rate for 22-week babies born alive who were given active treatment, and a 66% survival rate for 23-week babies.[14] A data review in the United Kingdom showed a 54% survival rate for 22-week babies given intensive care.[15] However, the authors note that the survival rates of infants may be overly positive as "there is the possibility of selection bias and survivors may represent a sub-group of 22 week gestation babies with more favourable risk factors".[15] A U.S. study showed a 39% survival rate for those given active treatment at 22 weeks and a 55% survival rate for those given active treatment when born at 23 weeks (mothers were given antenatal steroids for both age groups).[16] "I've been in this business for 40 years, and I've seen the threshold of viability move back about one week every 10 years or so in my practice," reports Edward Bell, a neonatologist at the University of Iowa Children's Hospital.[17]
Unfortunately, many babies in this age group are stillborn, meaning they are showing any signs of life when they are delivered; however, this percentage has been decreasing as antenatal treatment has improved. The aforementioned study in Sweden reported that between 2014-2016, 35% of 22-week infants were stillborn, and 29% of 23-week infants were stillborn.[14]
Older data have been less optimistic. According to studies between 2003 and 2005, 20 to 35 percent of babies born at 24 weeks of gestation survived, while 50 to 70 percent of babies born at 25 weeks, and more than 90 percent born at 26 to 27 weeks, survived.[18]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/5/57/Prenatal_development_table.svg/800px-Prenatal_development_table.svg.png)
Completed weeks of gestation at birth | 22 | 23 | 24 | 25 | 26 |
---|---|---|---|---|---|
Probability of survival if showing any sign of life at birth and given intensive care (based on individual studies) | Up to 61%[13] | Up to 71%[13] | 79%[14] | 88%[14] | 92%[14] |
Period of viability
Beliefs about viability vary by country. One study showed that in Sweden, neonatologists generally consider whether or not to give medical treatment to babies born at 22 weeks, whereas neonatologists in the Netherlands generally do not consider treating babies until 24 weeks gestation.[19] In 2019, the British Association of Perinatal Medicine recommended that physicians in the United Kingdom consider whether or not to treat babies born at 22 weeks, revising its previous recommendation of 24 weeks.[20] Whether the fetus is in the period of viability has legal ramifications as far as the fetus' rights of protection are concerned.[21] Traditionally, the period of viability referred to the period after the twenty-eighth week,[22]
Viability can incorporate weight as well as gestational age.[23][24][25]
United States Supreme Court
The United States Supreme Court stated in Roe v. Wade (1973) that viability (i.e., the "interim point at which the fetus becomes ... potentially able to live outside the mother's womb, albeit with artificial aid"[26]) "is usually placed at about seven months (28 weeks) but may occur earlier, even at 24 weeks."[26] The 28-week definition became part of the "trimester framework" marking the point at which the "compelling state interest" (under the doctrine of strict scrutiny) in preserving potential life became possibly controlling, permitting states to freely regulate and even ban abortion after the 28th week.[26] The subsequent Planned Parenthood v. Casey (1992) modified the "trimester framework," permitting the states to regulate abortion in ways not posing an "undue burden" on the right of the mother to an abortion at any point before viability; on account of technological developments between 1973 and 1992, viability itself was legally dissociated from the hard line of 28 weeks, leaving the point at which "undue burdens" were permissible variable depending on the technology of the time and the judgment of the state legislatures.
Born-Alive Infants Protection Act of 2002
In 2002, the U.S. Government enacted the Born-Alive Infants Protection Act. Whereas a fetus may be viable or not viable in utero, this law provides a legal definition for personal human life when not in utero. It defines "born alive" as "the complete expulsion or extraction from his or her mother of that member, at any stage of development, who after such expulsion or extraction breathes or has a beating heart, pulsation of the umbilical cord, or definite movement of voluntary muscles"[27] and specifies that any of these is the action of a living human person. While the implications of this law for defining viability in medicine may not be fully explored,[28] in practice doctors and nurses are advised not to resuscitate such persons with gestational age of 22 weeks or less, under 400 g weight, with anencephaly, or with a confirmed diagnosis of trisomy 13 or 18.[29][30]
U.S. state laws
Forty-three states have laws restricting post-viability abortions. Some allow doctors to decide for themselves if the fetus is viable. Some require doctors to perform tests to prove a fetus is pre-viable and require multiple doctors to certify the findings. The procedure intact dilation and extraction (IDX) became a focal point in the abortion debate,[31] based on the belief that it is used mainly post-viability.[32] IDX was made illegal in most circumstances by the Partial-Birth Abortion Ban Act in 2003, which the U.S. Supreme Court upheld in the case of Gonzales v. Carhart.
Limit of viability
The limit of viability is the gestational age at which a prematurely born fetus/infant has a 50% chance of long-term survival outside its mother's womb. With the support of neonatal intensive care units, the limit of viability in the developed world has declined since 50 years ago.[33][34]
Different jurisdictions have different policies regarding the resuscitation of extremely premature newborns, that may be based on various factors such as gestational age, weight and medical presentation of the baby, the desires of parents and medical practitioners. The risk of severe disability of very premature babies or of mortality despite medical efforts lead to ethical debates over quality of life and futile medical care, but also about the sanctity of life as viewed in various religious doctrines.[35] A majority will not have any severe disabilities; the British Association of Perinatal Medicine reports that 2/3 of 22-week babies will not have a severe disability, and 3/4 of 23-week babies will not have a severe disability; the British Association of Perinatal Medicine notes "disability is generally impossible to predict for an individual baby at birth".[15]
As of 2006[update], the two youngest children to survive premature birth are thought to be James Elgin Gill (born on 20 May 1987 in Ottawa, Ontario, Canada, at 21 weeks and 5 days gestational age),[36][37] and Amillia Taylor (an IVF pregnancy, born on 24 October 2006 in Miami, Florida, at 21 weeks and 6 days gestational age).[38][39] Both children were born just under 20 weeks from fertilization (or 22 weeks' gestation). At birth, Taylor was 9 inches (22.86 cm) long and weighed 10 ounces (283 grams).[38] She suffered digestive and respiratory problems, together with a brain hemorrhage. She was discharged from the Baptist Children's Hospital on 20 February 2007.[38] As of 2013, Taylor was in kindergarten and at the small end of the normal growth curve with some developmental delays.[40]
A preterm birth, also known as premature birth, is defined as babies born alive before 37 weeks of pregnancy are completed.[41] There are three types of preterm births: extremely preterm (less than 28 weeks), very preterm (28 to 32 weeks) and moderate to late preterm (32 to 37 weeks).[41]
Factors that influence the chance of survival
There are several factors that affect the chance of survival of the baby. Two notable factors are age and weight. The baby's gestational age (number of completed weeks of pregnancy) at the time of birth and the baby's weight (also a measure of growth) influence whether the baby will survive. Another major factor is gender: male infants are slightly less mature[clarification needed] and have a slightly higher risk of dying than female infants.[citation needed]
Several types of health problems also influence fetal viability. For example, breathing problems, congenital abnormalities or malformations, and the presence of other severe diseases, especially infection, threaten the survival of the neonate.
Other factors may influence survival by altering the rate of organ maturation or by changing the supply of oxygen to the developing fetus.
The mother's health plays a significant role in the child's viability. Diabetes in the mother, if not well controlled, slows organ maturation; infants of such mothers have a higher mortality. Severe high blood pressure before the 8th month of pregnancy may cause changes in the placenta, decreasing the delivery of nutrients and/or oxygen to the developing fetus and leading to problems before and after delivery.
Rupture of the fetal membranes before 24 weeks of gestation with loss of amniotic fluid markedly decreases the baby's chances of survival, even if the baby is delivered much later.[42]
The quality of the facility—whether the hospital offers neonatal critical care services, whether it is a Level I pediatric trauma care facility, the availability of corticosteroids and other medications at the facility, the experience and number of physicians and nurses in neonatology and obstetrics and of the providers has a limited but still significant impact on fetal viability. Facilities that have obstetrical services and emergency rooms and operating facilities, even if smaller, can be used in areas where higher services are not available to stabilize the mother and fetus or neonate until they can be transferred to an appropriate facility.[43][44][45][46]
See also
- Beginning of human personhood
- Futile medical care
- Office for Human Research Protections#Additional protection for pregnant women, human fetuses, and neonates
References
- ^ a b Moore, Keith and Persaud, T. The Developing Human: Clinically Oriented Embryology, p. 103 (Saunders 2003).
- ^ (2012). Fetal Viability. [ONLINE] Available at: http://www.reference.md/files/D005/mD005328.html. [Last Accessed 15 November 2012].
- ^ Breborowicz GH (January 2001). "Limits of fetal viability and its enhancement". Early Pregnancy. 5 (1): 49–50. PMID 11753511.
- ^ The Free Dictionary. "nonviable fetus". Medical Dictionary. Retrieved May 21, 2019.
- ^ "Non-Viable Fetus Law and Legal Definition". USLegal. Retrieved May 21, 2019.
- ^ "Health (Regulation of Termination of Pregnancy) Act 2018" (PDF). Irish parliament.
- ^ Patel RM, Rysavy MA, Bell EF, Tyson JE (June 2017). "Survival of Infants Born at Periviable Gestational Ages". Clinics in Perinatology. 44 (2): 287–303. doi:10.1016/j.clp.2017.01.009. PMC 5424630. PMID 28477661.
- ^ Costeloe KL, Hennessy EM, Haider S, Stacey F, Marlow N, Draper ES (December 2012). "Short term outcomes after extreme preterm birth in England: comparison of two birth cohorts in 1995 and 2006 (the EPICure studies)". BMH. 345: e7976. doi:10.1136/bmj.e7976. PMC 3514472. PMID 23212881.
- ^ Fellman V, Hellström-Westas L, Norman M, Westgren M, Källén K, Lagercrantz H, Marsál K, Serenius F, Wennergren M (June 2009). "One-year survival of extremely preterm infants after active perinatal care in Sweden". JAMA. 301 (21): 2225–33. doi:10.1001/jama.2009.771. PMID 19491184.
- ^ Ancel PY, Goffinet F, Kuhn P, Langer B, Matis J, Hernandorena X, et al. (March 2015). "Survival and morbidity of preterm children born at 22 through 34 weeks' gestation in France in 2011: results of the EPIPAGE-2 cohort study". JAMA Pediatrics. 169 (3): 230–8. doi:10.1001/jamapediatrics.2014.3351. PMID 25621457.
- ^ Boland RA, Davis PG, Dawson JA, Doyle LW (March 2017). "Outcomes of infants born at 22-27 weeks' gestation in Victoria according to outborn/inborn birth status". Archives of Disease in Childhood: Fetal and Neonatal Edition. 102 (2): F153–F161. doi:10.1136/archdischild-2015-310313. PMID 27531224.
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Further reading
- "Fetal Viability and Death" (PDF). United States. National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research. May 2006.