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| {iology & Community Health |volume=60 |issue=10 |pages=851–3 |pmid=16973530 |last2=Gunnell |first2=D |last3=Davey Smith |first3=G |pmc=2566050}}</ref> | |||
| {{other uses|Miscarriage of justice}} | |||
| {{Use mdy dates|date=May 2012}} | |||
| {{Infobox disease | |||
| | Name = Miscarriage | |||
| | Image = Human Embryo - Approximately 8 weeks estimated gestational age.jpg|right|thumb | |||
| | Caption = A complete spontaneous abortion at about six weeks after ], i.e. eight weeks from the ] (LMP) | |||
| | DiseasesDB = 29 | |||
| | ICD10 = {{ICD10|O|03||O|00}} | |||
| | ICD9 = {{ICD9|634}} | |||
| | ICDO = | |||
| | OMIM = | |||
| | MedlinePlus = 001488 | |||
| | eMedicineSubj = search | |||
| | eMedicineTopic = miscarriage | |||
| | MeshID = D000022 | |||
| }} | |||
| '''Miscarriage''' is the spontaneous end of a ] at a stage where the ] or ] is incapable of surviving independently. Miscarriage is the most common complication of early pregnancy.<ref>{{cite web |last1=Petrozza |first1=John C |authorlink2=Inna Berin |last2=Berin |first2=Inna |title=Recurrent Early Pregnancy Loss |work=eMedicine |publisher=WebMD |date=August 29, 2006 |url=http://www.emedicine.com/med/topic3241.htm |accessdate=January 12, 2011}}</ref><ref>{{cite web |title=Early Pregnancy Loss (Miscarriage) |work=Pregnancy Bliss |url=http://www.pregnancy-bliss.co.uk/miscarriage.html |accessdate=January 12, 2011 |first=J |last=Kabyemela}}{{MEDRS|date=May 2013}}</ref> | |||
| ==Terminology== | |||
| The medical terminology applied to women’s experiences during early pregnancy has changed over time.<ref name=pmid23429567>{{cite journal |doi=10.1136/medhum-2012-010284 |title='Miscarriage or abortion?' Understanding the medical language of pregnancy loss in Britain; a historical perspective |year=2013 |last1=Moscrop |first1=A. |journal=Medical Humanities |pmid=23429567}}</ref> “Miscarriage” or “early pregnancy loss” are currently used to describe the end of a pregnancy at a gestational stage before the fetus is considered viable. The age of ] may be variably defined in different countries and contexts, but is often said to be around 24 weeks gestation. A fetus that dies while in the uterus after this defined “limit of viability” is referred to as a stillbirth. Under UK law, all stillbirths should be registered, miscarriages are not.<ref>https://www.gov.uk/register-stillbirth{{full|date=May 2013}}</ref> | |||
| In the recent past, health professionals used the phrase “spontaneous abortion” interchangeably with “miscarriage”. However, many women who have had miscarriages object to the term "abortion" in connection with their experience, because in everyday English the word is strongly associated with induced abortions. Use of inappropriate terminology may cause women to feel that their experiences are not being recognised or appropriately acknowledged. {{Citation needed|This whole paragraph is unsourced and I feel like readers need to know more. When did the terms start being used interchangeably? Who objects? Who is telling women to feel their experiences are not recognized?|date=June 2013}} | |||
| In the late 1980s and 1990s, doctors became more conscious of their language in relation to early pregnancy loss. Some medical authors advocated change to use of "miscarriage" instead of "abortion" because this would be preferred by women patients.<ref>{{cite journal |pmid=2865589 |year=1985 |last1=Beard |first1=RW |last2=Mowbray |first2=JF |last3=Pinker |first3=GD |title=Miscarriage or abortion |volume=2 |issue=8464 |pages=1122–3 |journal=Lancet |doi=10.1016/S0140-6736(85)90709-3}}</ref><ref>{{cite journal |pmid=9774309 |pmc=1114078 |year=1998 |last1=Hutchon |first1=David J R |last2=Cooper |first2=Sandra |title=Terminology for early pregnancy loss must be changed |volume=317 |issue=7165 |pages=1081 |journal=BMJ |doi=10.1136/bmj.317.7165.1081}}</ref><ref>{{cite journal |doi=10.1016/S0002-9378(98)70370-9 |title=Understanding miscarriage or insensitive abortion: Time for more defined terminology? |year=1998 |last1=Hutchon |first1=David J.R. |journal=American Journal of Obstetrics and Gynecology |volume=179 |issue=2 |pages=397–8 |pmid=9731844}}</ref> In 2005 the European Society for Human Reproduction and Embryology (ESHRE) published a paper aiming to facilitate a revision of nomenclature used to describe early pregnancy events.<ref>{{cite journal |doi=10.1093/humrep/dei167 |title=Updated and revised nomenclature for description of early pregnancy events |year=2005 |last1=Farquharson |first1=R. G. |journal=Human Reproduction |volume=20 |issue=11 |pages=3008–11 |pmid=16006453 |last2=Jauniaux |first2=E |last3=Exalto |first3=N |author4=ESHRE Special Interest Group for Early Pregnancy}}</ref> | |||
| Historical analysis of the medical terminology applied to early pregnancy loss in Britain has shown that the use of "miscarriage" (instead of "spontaneous abortion") by doctors only occurred after changes in legislation (in the 1960s) and developments in ultrasound technology (in the early 1980s) allowed them to identify miscarriages without having to rely upon women's own description of events.<ref name=pmid23429567/> in countries where pregnancy termination remains illegal doctors may still not distinguish between "spontaneous" and "induced" abortions in clinical practice. | |||
| ] | |||
| ==Classification== | |||
| The clinical presentation of a ''threatened miscarriage'' describes any bleeding seen during pregnancy prior to viability, that has yet to be assessed further. At investigation it may be found that the fetus remains viable and the pregnancy continues without further problems. | |||
| Alternatively the following terms are used to describe pregnancies that do not continue: | |||
| * An ] is a condition where the gestational sac develops normally, while the embryonic part of the pregnancy is either absent or stops growing very early. Other terms for this condition are ''blighted ovum'' and ''anembryonic pregnancy''. | |||
| * An ''inevitable miscarriage'' describes a condition in which the cervix has already dilated open,<ref name="isbn0-07-144874-8">{{cite book |first1=Latha |last1=Stead |first2=S. Matthew |last2=Stead |first3=Matthew |last3=Kaufman |first4=Luis |last4=Suarez |title=First Aid for The Obstetrics and Gynecology Clerkship |publisher=McGraw-Hill |location=New York |year=2006 |page=138 |isbn=978-0-07-144874-1}}</ref> but the fetus has yet to be expelled. This usually will progress to a complete abortion. The fetal heart beat may have been shown to have stopped, but this is not part of the criteria. | |||
| * A ''complete miscarriage'' is when all products of conception have been expelled. ''Products of conception'' may include the ], ], ], ], and ] (]); or later in pregnancy the ], ], ], amniotic fluid, and ]. | |||
| * An ''incomplete miscarriage'' occurs when some ] has been passed, but some remains '']''.<!-- | |||
| --><ref name="MedlinePlus">{{cite web |author=MedlinePlus | authorlink =MedlinePlus | date = October 25, 2004 | url=http://www.nlm.nih.gov/medlineplus/ency/article/000904.htm | title =Abortion – incomplete | work=Medical Encyclopedia | accessdate =May 24, 2006 |archiveurl = http://web.archive.org/web/20060425090648/http://www.nlm.nih.gov/medlineplus/ency/article/000904.htm <!-- Bot retrieved archive --> |archivedate = April 25, 2006}}</ref> | |||
| * A ''missed miscarriage'' is when the embryo or fetus has died, but a miscarriage has not yet occurred. It is also referred to as ''delayed or missed miscarriage''. | |||
| The following two terms consider wider complications or implications of a miscarriage: | |||
| * A '']'' occurs when the tissue from a missed or incomplete miscarriage becomes infected. The infection of the uterus carries risk of spreading infection (]) and is a grave risk to the life of the woman. | |||
| * '']'' (RPL) or ''recurrent miscarriage'' is the occurrence of three consecutive miscarriages. If the proportion of pregnancies ending in miscarriage is 15% and assuming that miscarriages are independent events,<ref name="rcog2003"/> then the probability of two consecutive miscarriages is 2.25% and the probability of three consecutive miscarriages is 0.34%. The occurrence of recurrent pregnancy loss is 1%.<!-- | |||
| --><ref name="rcog2003">{{cite web | author=Royal College of Obstetricians and Gynaecologists | authorlink = Royal College of Obstetricians and Gynaecologists | year = 2003 | month = May | title =The investigation and treatment of couples with recurrent miscarriage |work=Green-top Guideline No. 17 |url=http://www.rcog.org.uk/womens-health/clinical-guidance/investigation-and-treatment-couples-recurrent-miscarriage-green-top- | accessdate = October 20, 2010}}</ref> A large majority (85%) of women who have had two miscarriages will conceive and carry normally afterward. | |||
| The physical symptoms of a miscarriage vary according to the length of pregnancy:<ref name="ausbirth">{{cite web | year = 2004 | month = October | title=miscarriage | url=http://www.birth.com.au/Info.asp?class=6620&page=13 | |||
| | accessdate = 0 March 2009 | author=www.birth.com.au}}{{dead link|date=May 2013}}</ref> | |||
| * At up to six weeks only small blood clots may be present, possibly accompanied by mild cramping or period pain. | |||
| * At 6 to 13 weeks a clot will form around the embryo or fetus, and the placenta, with many clots up to 5 cm in size being expelled prior to completion of the process. The process may take a few hours or be on and off for a few days. Symptoms vary widely and may include vomiting and loose bowels, possibly due to physical discomfort. | |||
| * At more than 13 weeks the fetus may be passed easily from the uterus, however the placenta is more likely to be fully or partially retained in the uterus, resulting in an incomplete abortion. The physical signs of bleeding, cramping, and pain may be similar to an early stage abortion, but sometimes more severe and labour-like. | |||
| ==Signs and symptoms== | |||
| The most common symptom of a miscarriage is bleeding;<!-- | |||
| --><ref name="risk factors">{{cite journal |doi=10.1097/01.AOG.0000183604.09922.e0 |title=Risk Factors for Spontaneous Abortion in Early Symptomatic First-Trimester Pregnancies |year=2005 |last1=Gracia |first1=Clarisa R. |last2=Sammel |first2=Mary D. |last3=Chittams |first3=Jesse |last4=Hummel |first4=Amy C. |last5=Shaunik |first5=Alka |last6=Barnhart |first6=Kurt T. |journal=Obstetrics & Gynecology |volume=106 |issue=5, Part 1 |pages=993–9 |pmid=16260517}}</ref> bleeding during pregnancy may be referred to as a ''threatened miscarriage''. Of women who seek clinical treatment for bleeding during pregnancy, about half will miscarry.<ref name="bmj1997" /> Symptoms other than bleeding are not statistically related.<ref name="risk factors" /> | |||
| Miscarriage may be detected during an ultrasound exam, or through serial ] (HCG) testing. Women pregnant from ] methods, and women with a history of aborting, may be monitored closely and so detection is sooner than women without such monitoring. | |||
| Several medical options exist for managing documented nonviable pregnancies that have not been expelled naturally. | |||
| ===Psychological=== | |||
| {{refimprove section|date=December 2011}} | |||
| Although a woman physically recovers from a miscarriage quickly, in general, psychological recovery for parents may take a long time. People differ greatly in this regard: some are able to move on after a few months, but others take more than a year. Still others may feel relief or other less negative emotions. A questionnaire (GHQ-12 General Health Questionnaire) study following women having aborted showed that half (55%) of them presented with significant psychological distress immediately, 25% at 3 months; 18% at 6 months, and 11% at 1 year after miscarriage.<ref>{{cite journal |doi=10.1016/j.fertnstert.2008.12.048 |title=A 1-year longitudinal study of psychological morbidity after miscarriage |year=2010 |last1=Lok |first1=Ingrid Hung |last2=Yip |first2=Alexander Shing-Kai |last3=Lee |first3=Dominic Tak-Sing |last4=Sahota |first4=Daljit |last5=Chung |first5=Tony Kwok-Hung |journal=Fertility and Sterility |volume=93 |issue=6 |pages=1966–75 |pmid=19185858}}</ref> | |||
| ] for miscarried ]s and ]es]] | |||
| Besides the feeling of loss, a lack of understanding by others is often important. People who have not experienced it themselves may find it difficult to ] with what has occurred, and how upsetting it may be. This may lead to unrealistic expectations of the parents' recovery. The pregnancy and the miscarriage cease to be mentioned in conversations, often because the subject is too painful. This may make the woman feel particularly isolated. Inappropriate or insensitive responses from the medical professionals can add to the distress and trauma experienced, so in some cases attempts have been made to draw up a standard code of practice.<ref></ref> | |||
| Often interaction with pregnant women and newborn children is painful for parents who have experienced miscarriage. Sometimes this makes interaction with friends, acquaintances, and family very difficult.<!-- | |||
| --><ref name="David Vernon">{{cite web |author=David Vernon | authorlink =David Vernon (writer) | year = 2005 | url=http://web.mac.com/david.vernon/iWeb/Having%20a%20Great%20Birth%20in%20Australia/Welcome%20-%20Great%20Birth.html | title =Having a Great Birth in Australia }}{{dead link|date=May 2013}}{{self-published inline|date=May 2013}}</ref> | |||
| ==Causes== | |||
| Miscarriage may occur for many reasons, not all of which can be identified. Some of these causes include genetic, uterine, or hormonal abnormalities, reproductive tract infections, and tissue rejection. | |||
| ===First trimester=== | |||
| Most clinically apparent miscarriages (two thirds to three-quarters in various studies) occur during the first trimester.<ref name="webmd">{{cite web | last = Rosenthal | first = M. Sara | title = The Second Trimester | work=The Gynecological Sourcebook | publisher=WebMD | year = 1999 | url = http://www.webmd.com/content/article/4/1680_51802.htm | accessdate = December 18, 2006 }}</ref><ref name="pmid12336441">{{cite journal |pmid=12336441 |year=1959 |last1=Francis |first1=O |title=An analysis of 1150 cases of abortions from the Government R.S.R.M. Lying-in Hospital, Madras |volume=10 |issue=1 |pages=62–70 |journal=Journal of obstetrics and gynaecology of India}}</ref> | |||
| Chromosomal abnormalities are found in more than half of embryos miscarried in the first 13 weeks.<ref>{{cite journal |pmid=7450760 |year=1980 |last1=Kajii |first1=T |last2=Ferrier |first2=A |last3=Niikawa |first3=N |last4=Takahara |first4=H |last5=Ohama |first5=K |last6=Avirachan |first6=S |title=Anatomic and chromosomal anomalies in 639 spontaneous abortuses |volume=55 |issue=1 |pages=87–98 |journal=Human genetics |doi=10.1007/BF00329132}}</ref> An embryo with a genetic problem has a 95% probability of miscarrying {{Citation needed|date=February 2013}}. Most chromosomal problems happen by chance, have nothing to do with the parents, and are unlikely to recur. Chromosomal problems due to a parent's genes are, however, a possibility. This is more likely to have been the cause in the case of a woman suffering repeated miscarriages, or if one of the parents has a child or other relatives with birth defects.<ref name="PDR Family Guide 1994">{{cite web |title=Miscarriage: Causes of Miscarriage |url=http://www.healthcentral.com/encyclopedia/408/626.html |publisher=HealthCentral.com |accessdate=July 26, 2012}}taken word-for-word from pp. 347–9 of: {{cite book |year=1994 |title=The PDR Family Guide to Women's Health and Prescription Drugs |location=Montvale, NJ |publisher=Medical Economics |isbn=1-56363-086-9 |chapter=What To Do When Miscarriage Strikes |pages=345–50}}</ref> Genetic problems are more likely to occur with older parents; this may account for the higher rates observed in older women.<!-- | |||
| --><ref>{{cite web | title = Pregnancy Over Age 30 | work=MUSC Children's Hospital | url = http://www.musckids.com/health_library/hrpregnant/over30.htm | accessdate = December 18, 2006 |archiveurl = http://web.archive.org/web/20061113233603/http://www.musckids.com/health_library/hrpregnant/over30.htm <!-- Bot retrieved archive --> |archivedate = November 13, 2006}}</ref> | |||
| ] deficiency may be another cause. Women diagnosed with low progesterone levels in the second half of their menstrual cycle (]) may be prescribed progesterone supplements, to be taken for the first trimester of pregnancy.<ref name="PDR Family Guide 1994" /> No study has shown that general first-trimester progesterone supplements reduce the risk however, (when a mother might already be losing her baby),<ref name="Cochrane">{{cite journal |doi=10.1002/14651858.CD005943.pub2 |title=Progestogen for treating threatened miscarriage |journal=Cochrane Database of Systematic Reviews |year=2007 |last1=Wahabi |first1=Hayfaa A |last2=Abed Althagafi |first2=Nuha F |last3=Elawad |first3=Mamoun |last4=Al Zeidan |first4=Rasmieh A |editor1-last=Wahabi |editor1-first=Hayfaa A |pmid=22161393 |url=http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0013622/ |issue=12 |pages=CD005943}}</ref> and even the identification of problems with the luteal phase as a contributing factor has been questioned.<ref>{{cite journal |doi=10.1016/j.ogc.2004.08.007 |title=Luteal phase defect: Myth or reality |year=2004 |last1=Bukulmez |first1=Orhan |last2=Arici |first2=Aydin |journal=Obstetrics and Gynecology Clinics of North America |volume=31 |issue=4 |pages=727–44, ix |pmid=15550332}}</ref> | |||
| ===Second trimester=== | |||
| Up to 15% of pregnancy losses in the second trimester may be due to ], growths in the uterus (]), or ].<ref name="PDR Family Guide 1994" /> These conditions also may contribute to ].<ref name="webmd" /> | |||
| One study found that 19% of second trimester losses were caused by problems with the ]. Problems with the ] also may account for a significant number of later-term miscarriages.<!-- | |||
| --><ref>{{cite journal |doi=10.2350/05-05-0051.1 |title=Umbilical Cord Stricture and Overcoiling Are Common Causes of Fetal Demise |year=2006 |last1=Peng |first1=Hong Qi |last2=Smith-Levitin |first2=Michelle |last3=Rochelson |first3=Burton |last4=Kahn |first4=Ellen |journal=Pediatric and Developmental Pathology |volume=9 |pages=14–9 |pmid=16808633 |issue=1}}</ref> | |||
| ==Risk factors== | |||
| Pregnancies involving more than one fetus are considered at increased risk.<ref name="PDR Family Guide 1994" /> | |||
| The risk of miscarriage is increased in women with poorly controlled insulin-dependent diabetes mellitus.<ref>{{cite journal |doi=10.1056/NEJM198812223192501 |title=Incidence of Spontaneous Abortion among Normal Women and Insulin-Dependent Diabetic Women Whose Pregnancies Were Identified within 21 Days of Conception |year=1988 |last1=Mills |first1=James L. |last2=Simpson |first2=Joe Leigh |last3=Driscoll |first3=Shirley G. |last4=Jovanovic-Peterson |first4=Lois |last5=Van Allen |first5=Margot |last6=Aarons |first6=Jerome H. |last7=Metzger |first7=Boyd |last8=Bieber |first8=Frederick R. |last9=Knopp |first9=Robert H. |journal=New England Journal of Medicine |volume=319 |issue=25 |pages=1617–23 |pmid=3200277}}</ref> This 1998 prospective study found that the risk increased by 3.1% (over the background risk of about 16%) for each standard deviation in glycosylated haemoglobin above the normal range. The risk was not found to be significantly increased in women with good glycaemic control in early pregnancy. | |||
| ] is a risk factor, with 30–50% of pregnancies in women with PCOS being aborted during the first trimester{{citation needed|date=February 2013}}. Two studies have shown treatment with the drug ] significantly lowers the rate of miscarriage in women with PCOS (the metformin-treated groups experienced approximately one-third the miscarriage rates of the control groups).<ref>{{cite journal |doi=10.1210/jc.87.2.524 |title=Effects of Metformin on Early Pregnancy Loss in the Polycystic Ovary Syndrome |year=2002 |last1=Jakubowicz |first1=D. J. |journal=Journal of Clinical Endocrinology & Metabolism |volume=87 |issue=2 |pages=524–9 |pmid=11836280 |last2=Iuorno |first2=MJ |last3=Jakubowicz |first3=S |last4=Roberts |first4=KA |last5=Nestler |first5=JE}}</ref><ref>{{cite journal |doi=10.1080/09513590601010508 |title=Metformin reduces abortion in pregnant women with polycystic ovary syndrome |year=2006 |last1=Khattab |first1=Sherif |last2=Mohsen |first2=Iman Abdel |last3=Foutouh |first3=Ismail Aboul |last4=Ramadan |first4=Ashraf |last5=Moaz |first5=Mohamed |last6=Al-Inany |first6=Hesham |journal=Gynecological Endocrinology |volume=22 |issue=12 |pages=680–4 |pmid=17162710}}</ref> A 2006 review of metformin treatment in pregnancy found insufficient evidence of safety, however, and did not recommend routine treatment with the drug.<ref>{{cite journal |doi=10.1080/00016340600780441 |title=Polycystic ovary syndrome and metformin in pregnancy |year=2006 |last1=Lilja |first1=Anna E. |last2=Mathiesen |first2=Elisabeth R. |journal=Acta Obstetricia et Gynecologica Scandinavica |volume=85 |issue=7 |pages=861–8 |pmid=16817087}}</ref> | |||
| ] during pregnancy, known as ], is sometimes caused by an inappropriate immune reaction (]) to the developing fetus, and is associated with the risk of miscarriage. Similarly, women with a history of recurrent miscarriage are at risk of developing preeclampsia.<ref name=Trogstad>{{cite journal |doi=10.1111/j.1471-0528.2008.01978.x |title=The effect of recurrent miscarriage and infertility on the risk of pre-eclampsia |year=2009 |last1=Trogstad |first1=L |last2=Magnus |first2=P |last3=Moffett |first3=A |last4=Stoltenberg |first4=C |journal=BJOG |volume=116 |pages=108–13 |pmid=19087081 |issue=1}}</ref> | |||
| Severe cases of ] increase the risk of miscarriage. The effect of milder cases of hypothyroidism on miscarriage rates has not been established. The presence of certain immune conditions such as ]s is associated with a greatly increased risk.<ref name="PDR Family Guide 1994" /> The presence of ] is associated with an increased risk with an ] of 3.73 and 95% ] 1.8–7.6.<ref>{{cite journal |doi=10.1093/humupd/dmr024 |title=Significance of (sub)clinical thyroid dysfunction and thyroid autoimmunity before conception and in early pregnancy: A systematic review |year=2011 |last1=Van Den Boogaard |first1=E. |last2=Vissenberg |first2=R. |last3=Land |first3=J. A. |last4=Van Wely |first4=M. |last5=Van Der Post |first5=J. A. M. |last6=Goddijn |first6=M. |last7=Bisschop |first7=P. H. |journal=Human Reproduction Update |volume=17 |issue=5 |pages=605–19 |pmid=21622978}}</ref> | |||
| Certain illnesses (such as ] and ]) increase the risk.<ref name="PDR Family Guide 1994" /> | |||
| {{See also|Smoking and pregnancy}} | |||
| Tobacco (cigarette) smokers have an increased risk of miscarriage.<!-- | |||
| --><ref name="x">{{cite journal |doi=10.1056/NEJM199902043400501 |title=Cocaine and Tobacco Use and the Risk of Spontaneous Abortion |year=1999 |last1=Ness |first1=Roberta B. |last2=Grisso |first2=Jeane Ann |last3=Hirschinger |first3=Nancy |last4=Markovic |first4=Nina |last5=Shaw |first5=Leslie M. |last6=Day |first6=Nancy L. |last7=Kline |first7=Jennie |journal=New England Journal of Medicine |volume=340 |issue=5 |pages=333–9 |pmid=9929522}}</ref> An increase in the rates also is associated with the father being a cigarette smoker.<!-- | |||
| --><ref name="paternal smoking">{{cite journal |doi=10.1093/aje/kwh128 |title=Paternal Smoking and Pregnancy Loss: A Prospective Study Using a Biomarker of Pregnancy |year=2004 |last1=Venners |first1=S. A. |journal=American Journal of Epidemiology |volume=159 |issue=10 |pages=993–1001 |pmid=15128612 |last2=Wang |first2=X |last3=Chen |first3=C |last4=Wang |first4=L |last5=Chen |first5=D |last6=Guang |first6=W |last7=Huang |first7=A |last8=Ryan |first8=L |last9=O'Connor |first9=J}}</ref> The husband study observed a 4% increased risk for husbands who smoke fewer than 20 cigarettes/day, and an 81% increased risk for husbands who smoke 20 or more cigarettes/day. | |||
| Cocaine use increases the rates.<ref name="x" /> Physical trauma, exposure to environmental toxins, and use of an ] during the time of conception have also been linked to increased risk.<ref name=health.am>{{cite web | title =Miscarriage: An Overview | publisher=Armenian Medical Network | url=http://www.health.am/pregnancy/more/miscarriage_an_overview/ | year = 2005 | accessdate=September 19, 2007}}</ref> | |||
| ] especially ] and ] can lead to spontaneous abortion.<ref>{{cite journal |pmid=19863482 |year=2010 |last1=Broy |first1=P |last2=Bérard |first2=A |title=Gestational exposure to antidepressants and the risk of spontaneous abortion: A review |volume=7 |issue=1 |pages=76–92 |journal=Current drug delivery |doi=10.2174/156720110790396508}}</ref><ref>{{cite journal |doi=10.1503/cmaj.091208 |title=Use of antidepressants during pregnancy and the risk of spontaneous abortion |year=2010 |last1=Nakhai-Pour |first1=H. R. |last2=Broy |first2=P. |last3=Berard |first3=A. |journal=Canadian Medical Association Journal |volume=182 |issue=10 |pages=1031–7 |pmid=20513781 |pmc=2900326}}</ref> | |||
| {{Further|Advanced maternal age}} | |||
| The age of the mother is a significant risk factor. Miscarriage rates increase steadily with age, with more substantial increases after age 35.<ref>{{cite journal |doi=10.1136/jech.2005.045179 |title=Advanced paternal age: How old is too old? |year=2006 |last1=Bray |first1=I. |journal=Journal of Epidemiology & Community Health |volume=60 |issue=10 |pages=851–3 |pmid=16973530 |last2=Gunnell |first2=D |last3=Davey Smith |first3=G |pmc=2566050}}</ref> | |||
| Several other factors have been correlated with higher rates in some research, but whether they cause the miscarriages is debated. No causal mechanism may be known, the studies showing a correlation may have been retrospective (beginning the study after the miscarriages occurred, which may introduce bias) rather than prospective (beginning the study before the women became pregnant), or both. A greater correlation has been shown in the following categories, however. | Several other factors have been correlated with higher rates in some research, but whether they cause the miscarriages is debated. No causal mechanism may be known, the studies showing a correlation may have been retrospective (beginning the study after the miscarriages occurred, which may introduce bias) rather than prospective (beginning the study before the women became pregnant), or both. A greater correlation has been shown in the following categories, however. | ||
Revision as of 01:22, 7 June 2013
{iology & Community Health |volume=60 |issue=10 |pages=851–3 |pmid=16973530 |last2=Gunnell |first2=D |last3=Davey Smith |first3=G |pmc=2566050}}</ref>
Several other factors have been correlated with higher rates in some research, but whether they cause the miscarriages is debated. No causal mechanism may be known, the studies showing a correlation may have been retrospective (beginning the study after the miscarriages occurred, which may introduce bias) rather than prospective (beginning the study before the women became pregnant), or both. A greater correlation has been shown in the following categories, however.
Autoimmune disease
Some research suggests autoimmunity as a possible cause of recurrent or late-term miscarriages. Autoimmune disease occurs when the body's own immune system acts against itself. Therefore, in the case of an autoimmune-induced miscarriages the woman's body attacks the growing fetus or prevents normal pregnancy progression. Further research also has suggested that autoimmune disease may cause genetic abnormalities in embryos which in turn may lead to miscarriage.
Morning sickness
Nausea and vomiting of pregnancy (NVP, or morning sickness) are associated with a decreased risk. Several mechanisms have been proposed for this relationship, but none are widely agreed upon. Because NVP may alter a woman's food intake and other activities during pregnancy, it may be a confounding factor when investigating possible causes of miscarriage.
Exercise
Another factor is exercise. A study of more than 92,000 pregnant women found that most types of exercise (with the exception of swimming) correlated with a higher risk of miscarrying prior to 18 weeks. Increasing time spent on exercise was associated with a greater risk: an approximately 10% increased risk was seen with up to 1.5 hours per week of exercise, and a 200% increased risk was seen with more than 7 hours per week of exercise. High-impact exercise was especially associated with the increased risk. No relationship was found between exercise rates after the 18th week of pregnancy. The majority of miscarriages had already occurred at the time women were recruited for the study, and no information on nausea during pregnancy or exercise habits prior to pregnancy was collected.
Caffeine
Caffeine consumption also has been correlated to miscarriage rates, at least at higher levels of intake. A 2007 study of more than 1,000 pregnant women found that those who reported consuming 200 mg or more of caffeine per day experienced a 25% rate, compared to 13% among women who reported no caffeine consumption. 200 mg of caffeine is present in 10 oz (300 mL) of coffee or 25 oz (740 mL) of tea. This study controlled for pregnancy-associated nausea and vomiting (NVP or morning sickness): the increased rate for heavy caffeine users was seen regardless of how NVP affected the women. About half of the miscarriages had already occurred at the time women were recruited for the study. A second 2007 study of approximately 2,400 pregnant women found that caffeine intake up to 200 mg per day was not associated with increased rates (the study did not include women who drank more than 200 mg per day past early pregnancy). A prospective cohort study in 2009 found that light or moderate caffeine consumption (up to 300 mg per day) had no effect on pregnancy or miscarriage rates.
Diagnosis
A miscarriage may be confirmed via ultrasound and by the examination of the passed tissue. When looking for microscopic pathologic symptoms, one looks for the products of conception. Microscopically, these include villi, trophoblast, fetal parts, and background gestational changes in the endometrium. Genetic tests also may be performed to look for abnormal chromosome arrangements.
Management
Bleeding during early pregnancy is the most common symptom of both impending miscarriage and of ectopic pregnancy. Pain does not strongly correlate with the former, but is a common symptom of ectopic pregnancy. Typically, in the case of blood loss, pain, or both, transvaginal ultrasound is performed. If a viable intrauterine pregnancy is not found with ultrasound, serial βHCG tests should be performed to rule out ectopic pregnancy, which is a life-threatening situation.
If the bleeding is light, making an appointment to see one's doctor is recommended. If bleeding is heavy, there is considerable pain, or there is a fever, then seeking emergency medical attention is recommended.
Whilst bed rest has been advocated in the past to help ensure that a threatened pregnancy might continue, and in one study possibly helped when small subchorionic hematoma had been found on ultrasound scans, the prevailing opinion is that this is of no proven benefit.
No treatment is necessary for a diagnosis of complete miscarriage (so long as ectopic pregnancy is ruled out). In cases of an incomplete miscarriage, empty sac, or missed abortion there are three treatment options:
- With no treatment (watchful waiting), most of these cases (65–80%) will pass naturally within two to six weeks. This path avoids the side effects and complications possible from medications and surgery, but increases the risk of mild bleeding, need for unplanned surgical treatment, and incomplete miscarriage.
- Medical management usually consists of using misoprostol (a prostaglandin, brand name Cytotec) to encourage completion of the natural process. About 95% of cases treated with misoprostol will complete within a few days.
- Surgical treatment (most commonly vacuum aspiration, sometimes referred to as a D&C or D&E) is the fastest way to complete the process. It also shortens the duration and heaviness of bleeding, and avoids the physical pain associated with the miscarriage. In cases of repeated spontaneous abortions, D&C is also the most convenient way to obtain tissue samples for karyotype analysis (cytogenetic or molecular), although it is also possible to do with expectant and medical management. D&C, however, has a higher risk of complications, including risk of injury to the cervix (e.g. cervical incompetence) and uterus, perforation of the uterus, and potential scarring of the intrauterine lining (Asherman's syndrome). This is an important consideration for women who would like to have children in the future and want to preserve their fertility and reduce the chance of future obstetric complications.
Prevention
Currently there is no known way to prevent an impending miscarriage, however, fertility experts believe that identifying the cause of the miscarriage may help prevent it from happening again in a future pregnancy.
Epidemiology
Determining the prevalence of miscarriage is difficult. Many happen very early in the pregnancy, before a woman may know she is pregnant. Treatment of women without hospitalization means medical statistics misses many cases. Prospective studies using very sensitive early pregnancy tests have found that 25% of pregnancies abort by the sixth week LMP (since the woman's last menstrual period), however, other reports suggest higher rates. One fact sheet from the University of Ottawa states, "The incidence of spontaneous abortion is estimated to be 50% of all pregnancies, based on the assumption that many pregnancies abort spontaneously with no clinical recognition." The NIH reports, "It is estimated that up to half of all fertilized eggs die and are lost (aborted) spontaneously, usually before the woman knows she is pregnant. Among those women who know they are pregnant, the miscarriage rate is about 15–20%." Clinical miscarriages (those occurring after the sixth week LMP) occur in 8% of pregnancies.
The risk of miscarrying decreases sharply after the 10th week LMP, i.e., when the fetal stage begins. The loss rate between 8.5 weeks LMP and birth is about two percent; loss is “virtually complete by the end of the embryonic period."
The prevalence increases considerably with age of the parents. One study found that pregnancies from men younger than 25 years are 40% less likely to end in miscarriage than pregnancies from men 25–29 years. The same study found that pregnancies from men older than 40 years are 60% more likely to end in miscarriage than the 25–29-year age group. Another study found that the increased risk in pregnancies from older men is mainly seen in the first trimester. Yet another study found an increased risk in women, by the age of 45, on the order of 800% (compared to the 20–24 age group in that study), 75% of pregnancies ended in miscarriage.
The estimate on the number of annual miscarriages in the United States range from as low as 500,000 to over one million.
In non-human animals
Miscarriage occurs in all animals that experience pregnancy. There are a variety of known risk factors for it in non-human animals. For example, in sheep, it may be caused by crowding through doors, or being chased by dogs. In cows, spontaneous abortion may be caused by contagious disease, such as Brucellosis or Campylobacter, but often can be controlled by vaccination. Other diseases are also known to make animals susceptible. Spontaneous abortion occurs in pregnant Prairie Voles when their mate is removed and they are exposed to a new male, an example of the Bruce effect, although this effect is seen less in wild populations than in the laboratory. Female mice who had spontaneous abortions showed a sharp rise in the amount of time spent with unfamiliar males preceding the abortion than those who did not abort.
ICD10 codes
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See also
References
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External links
- Miscarriage Association (http://www.miscarriageassociation.org.uk). Provides information and support for women experiencing miscarriage and other early pregnancy problems.
- Template:Dmoz
- UnspokenGrief ™.com | understanding & support for miscarriage survivors. support network
- The causes of recurrent miscarriages in detail
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