Abortion

Miscarriage or spontaneous abortion is the spontaneous end of a pregnancy at a stage where the embryo or fetus is incapable of surviving independently, generally defined in humans at prior to 20 weeks of gestation. Miscarriage is the most common complication of early pregnancy.[1][2]
Contents
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• 1 Terminology
• 2 Classification
• 3 Signs and symptoms
o 3.1 Psychological
• 4 Causeso 4.1 First trimester
o 4.2 Second trimester
o 4.3 General risk factors
o 4.4 Suspected risk factors
 4.4.1 Autoimmune disease
 4.4.2 Morning sickness
 4.4.3 Exercise
 4.4.4 Caffeine
• 5 Diagnosis
• 6 Management
• 7 Prevention
• 8 Epidemiology
• 9 In other animals
• 10 ICD10 codes
• 11 See also
• 12 References
• 13 External links

[edit] Terminology
Very earlymiscarriages—those that occur before the sixth week LMP (since the woman's Last Menstrual Period)—are medically termed early pregnancy loss[3] or chemical pregnancy.[4] Miscarriages that occur after the sixth week LMP are medically termed clinical spontaneous abortion.[3]
In medical (and veterinary) contexts, the technical term "abortion" refers to any process by which a pregnancy ends with the death and removalor expulsion of the fetus, regardless of whether it is spontaneous or intentionally induced. Many women who have had miscarriages, however, object to the term "abortion" in connection with their experience, because in everyday English the word is strongly associated with induced abortions. In recent years there has been discussion in the medical community about avoiding the use of this term infavor of the less ambiguous term "miscarriage".[5] In 2005 the European Society for Human Reproduction and Embryology (ESHRE) published a paper aiming to facilitate an update and revision of nomenclature used to describe early pregnancy events.[6]
Labour resulting in live birth before the 37th week of pregnancy is termed "premature birth", even if the infant dies shortly afterward. The limit ofviability at which 50% of fetus/infants survive longterm is around 24 weeks, with moderate or major neurological disability dropping to 50% only by 26 weeks.[7] Although long-term survival has never been reported for infants born from pregnancy shorter than 21 weeks and 5 days,[8] fetuses born as early as the 16th week of pregnancy may sometimes live for some minutes after birth.[9]
A fetus thatdies while in the uterus after about the 20–24th week of pregnancy is termed a "stillbirth"; the precise gestational age definition varies by country. Premature births or stillbirths are not generally considered miscarriages, though usage of the terms and causes of these events may overlap.

Miscarriage of a fetus is also called intrauterine fetal demise (IUFD).
[edit] Classification
Theclinical presentation of a threatened abortion 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 empty sac is a condition where thegestational 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 abortion describes a condition in which the cervix has already dilated open,[10] but the fetus has yet to be expelled. This usually will progress to a complete abortion. The fetal heart beat mayhave been shown to have stopped, but this is not part of the criteria.
• A complete abortion is when all products of conception have been expelled. Products of conception may include the trophoblast, chorionic villi, gestational sac, yolk sac, and fetal pole (embryo); or later in pregnancy the fetus, umbilical cord, placenta, amniotic fluid, and amniotic membrane.
• An incomplete abortion...