Editing Abortion (section)

===Spontaneous===
{{Main|Miscarriage}}
Miscarriage, also known as spontaneous abortion, is the unintentional expulsion of an embryo or fetus before the 24th [[Gestational age (obstetrics)|week of gestation]].<ref>{{cite book | title = Churchill Livingstone medical dictionary | publisher = Churchill Livingstone Elsevier | location = Edinburgh New York | year = 2008 | isbn = 978-0-443-10412-1 | quote = The preferred term for unintentional loss of the product of conception prior to 24 weeks' gestation is miscarriage.}}</ref> A pregnancy that ends before 37 weeks of gestation resulting in a [[live birth (human)|live-born]] infant is a "[[premature birth]]" or a "preterm birth".<ref>{{cite book|quote=A preterm birth is defined as one that occurs before the completion of 37 menstrual weeks of gestation, regardless of birth weight.|page=669| veditors = Gabbe SG, Niebyl JR, Simpson JL |editor1-link=Steven Gabbe|year=2007|title=Obstetrics: Normal and Problem Pregnancies|edition=5th |publisher=Churchill Livingstone|chapter=51. Legal and Ethical Issues in Obstetric Practice|isbn=978-0-443-06930-7|vauthors = AnnasGJ, Elias S |author-link1=George Annas }}</ref> When a fetus dies [[Uterus|in utero]] after [[Fetal viability|viability]], or during [[childbirth|delivery]], it is usually termed "[[stillbirth|stillborn]]".<ref>{{cite encyclopedia|quote=birth of a fetus that shows no evidence of life (heartbeat, respiration, or independent movement) at any time later than 24 weeks after conception|title=Stillbirth|series=Concise Medical Dictionary|publisher=Oxford University Press|year=2010|url=https://books.google.com/books?id=Zs8ZM4OUurcC&pg=PA698|url-status=live|archive-url=https://web.archive.org/web/20151015195038/https://books.google.com/books?id=Zs8ZM4OUurcC&pg=PA698|archive-date=15 October 2015|isbn=978-0-19-955714-1}}</ref> [[Premature births]] and [[stillbirth]]s are generally not considered to be miscarriages, although usage of these terms can sometimes overlap.<ref>{{cite web|url=https://fam.state.gov/FAM/07FAM/07FAM1470.html|title=7 FAM 1470 Documenting Stillbirth (Fetal Death)|publisher=United States Department of State|date=18 February 2011|access-date=12 January 2016|archive-url=https://web.archive.org/web/20160205060246/https://fam.state.gov/FAM/07FAM/07FAM1470.html|archive-date=5 February 2016|url-status=live}}</ref>

Studies of pregnant women in the US and China have shown that between 40% and 60% of embryos do not progress to birth.<ref name="Gabbe, Chp 24">{{cite book | veditors = Gabbe SG, Niebyl JR, Simpson JL |editor1-link=Steven Gabbe |year=2007|title=Obstetrics: Normal and Problem Pregnancies|edition=5th |publisher=Churchill Livingstone |chapter=24. Pregnancy loss|isbn=978-0-443-06930-7| vauthors = Annas GJ, Elias S |author-link1=George Annas }}</ref><ref>{{cite journal |title=Early embryo mortality in natural human reproduction: What the data say [version 2; peer review: 2 approved, 1 approved with reservations] |journal=F1000Research |date=7 June 2017 | vauthors = Jarvis GE |volume=5 |page=2765 |doi=10.12688/f1000research.8937.2 |doi-access=free |pmid=28580126 |pmc=5443340 }}</ref><ref>{{cite journal |title=Estimating limits for natural human embryo mortality [version 1; peer review: 2 approved] |journal=F1000Research |date=26 August 2016 |vauthors=Jarvis GE |volume=5 |page=2083 |doi=10.12688/f1000research.9479.1 |doi-access=free |pmid=28003878 |pmc=5142718 }}</ref> The vast majority of miscarriages occur before the woman is [[clinically silent|aware that she is pregnant]],<ref name="Williams Gyn, Chp 6" /> and many pregnancies spontaneously abort before medical practitioners can detect an embryo.<ref>{{cite book| vauthors = Katz VL |publisher=Mosby|year=2007|edition=5 th|title=Katz: Comprehensive Gynecology| veditors = Katz VL, Lentz GM, Lobo RA, Gershenson DM |chapter=16. Spontaneous and Recurrent Abortion&nbsp;– Etiology, Diagnosis, Treatment|isbn=978-0-323-02951-3}}</ref> Between 15% and 30% of known pregnancies end in clinically apparent miscarriage, depending upon the age and health of the pregnant woman.<ref>{{cite book| vauthors = Stovall TG |chapter=17. Early Pregnancy Loss and Ectopic Pregnancy|title=Novak's Gynecology| veditors = Berek JS |editor1-link=Jonathan Berek|publisher=Lippincott Williams & Wilkins|year=2002|edition=13|isbn=978-0-7817-3262-8}}</ref> 80% of these spontaneous abortions happen in the first trimester.<ref name=Williams18>{{cite book | veditors = Cunningham FG, Leveno KJ, Bloom SL, Spong CY, Dashe JS, Hoffman BL, Casey BM, Sheffield JS |editor-link4=Catherine Y. Spong  |title = Williams Obstetrics |edition = 24th |year = 2014 |publisher = McGraw Hill Education |isbn = 978-0-07-179893-8}}</ref>

The most common cause of spontaneous abortion during the first trimester is [[chromosomal abnormalities]] of the embryo or fetus,<ref name="Williams Gyn, Chp 6">{{cite book| veditors = Schorge JO, Schaffer JI, Halvorson LM, Hoffman BL, Bradshaw KD, Cunningham FG |year=2008|title=Williams Gynecology|edition=1|publisher=McGraw-Hill Medical|isbn=978-0-07-147257-9|chapter=6. First-Trimester Abortion}}</ref><ref name="mednet">{{cite web|url=http://www.medicinenet.com/miscarriage/page1.htm |title=Miscarriage (Spontaneous Abortion) |access-date=7 April 2009 | vauthors = Stöppler MS | veditors = Shiel Jr WC |work=MedicineNet.com |publisher=WebMD |url-status=dead |archive-url=https://web.archive.org/web/20040829013142/http://www.medicinenet.com/Miscarriage/page1.htm |archive-date=29 August 2004 }}</ref> accounting for at least 50% of sampled early pregnancy losses.<ref name="fetal med 837">{{cite book |vauthors=Jauniaux E, Kaminopetros P, El-Rafaey H |chapter=Early pregnancy loss |veditors=Whittle MJ, Rodeck CH |title=Fetal medicine: basic science and clinical practice |publisher=Churchill Livingstone |location=Edinburgh |year=1999 |chapter-url=https://archive.org/details/fetalmedicinebas0000unse/page/836/mode/2up |isbn=978-0-443-05357-3 |oclc=42792567 |page=837 }}</ref> Other causes include [[vascular disease]] (such as [[Systemic lupus erythematosus|lupus]]), [[diabetes mellitus|diabetes]], other [[Endocrine disease|hormonal problems]], infection, and abnormalities of the uterus.<ref name="mednet" /> Advancing maternal age and a woman's history of previous spontaneous abortions are the two leading factors associated with a greater risk of spontaneous abortion.<ref name="fetal med 837" /> A spontaneous abortion can also be caused by accidental [[Physical trauma|trauma]]; intentional trauma or stress to cause miscarriage is considered induced abortion or [[feticide]].<ref name="Fetal Homicide Laws">{{cite web |url=http://www.ncsl.org/programs/health/fethom.htm |title=Fetal Homicide Laws |access-date=7 April 2009 |publisher=National Conference of State Legislatures |archive-url=https://archive.today/20120911171355/http://www.ncsl.org/issues-research/health/fetal-homicide-state-laws.aspx |archive-date=11 September 2012}}{{cbignore|bot=medic}}</ref>