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Revision as of 03:20, 19 April 2005 by Ekem (talk | contribs)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)"Miscarriage" is the lay term for the natural or accidental termination of a pregnancy at a stage where the fetus is incapable of surviving. The medical term for it is "abortion"; when the abortion is not deliberately induced, it is termed a "spontaneous abortion," so that is a synonym for "miscarriage." Medically, all pregnancy losses prior to 20 weeks gestation are considered miscarriages or abortions.
- Miscarriages are the most common complication of pregnancy.
Timing
Most such terminations occur very early in pregnancy, during the first trimester, and many people restrict the term "miscarriage" to early losses. Pregnancy losses in the second trimester are much less common. Miscarriages frequently occur so early that the woman is not even aware that she is pregnant; these are preclinical pregnancy losses. Some women are prone to miscarry; the term "habitual abortion" is more and more replaced by "recurrent pregnancy loss" (RPL) and describes the condition where two or three consecutive pregnancies have terminated before 20 weeks gestation.
Types
If a pregnant woman has vaginal bleeding, she is said to have a "threatened abortion", most patients with first trimester bleeding will be found to have a subchorionic hematoma and do well. In a minority such bleeding will progress to a pregnancy loss. With pain and opening of the cervix a woman is about to have an "inevitable abortion", which indicates that she has an absolute probability of miscarrying. If some of the tissue remains in the uterus after a passing some tissue, this is called an "incomplete abortion". If the tissue in the uterus gets infected, it is a "septic abortion". In some cases the fetus dies, but the uterus does not expell the pregnancy:- this is called a a "missed abortion". A "blighted ovum" pregnancy is a form of a miscarrage where the fetus either did not form, or died early, and the pregnancy consists only of trophoblastic tissue. A specific form of a miscarriage is the ectopic pregnancy.
Pathology
When looking for gross or microscopic pathologic symptoms of miscarriage, one looks for the products of conception. Microscopically, these include villi, trophoblast, fetal parts, and background gestational changes in the endometrium. Cytogenetic studies show that half or more of first trimester pregnancy losses have abnormal chromosome arrangements.
Causes
Miscarriages can occur for many reasons, not all of which can be identified. First trimester losses are in many if not most cases due to aneuploidy. Other possible causes are a uterine malformation (uterine septum), or hormonal abnormalities. Other possible but much less common causes include physical trauma, exposure to certain chemicals, infection, and immune factors. Pregnancy losses in the second trimester may be due to fetal abnormalities, uterine malformation, cervical problems, infection, trauma, immune factors, and medical disease.
Assessment
Transvaginal ultrasonography has become the primary method of assessment of the health of an early pregnancy.
Management
If a miscarriage is complete, and bleeding is contained and limited, only expectant management may be necessary. Excessive or prolonged bleeding needs medical attention. Often a D&C is indicated to remove tissue from the uterus. Tissue examination, including cytogenetic studies are helpful to determine the cause of the pregnancy loss. Febrile miscarriages need medical attention. Severe lower abdominal pain may indicate an ectopic pregnancy and needs medical attention.
External links
See also: childbirth, stillbirth, premature birth
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