Miscarriage or spontaneous abortion is the natural or accidental termination of a pregnancy at a stage where the embryo or the fetus is incapable of surviving, generally defined at a gestation of prior to 20 weeks. Miscarriages are the most common complication of pregnancy. The term "abortion" refers to any terminated pregnancy, deliberately induced or spontaneous, although in common parlance it refers specifically to active termination of pregnancy.
The most common symptoms of a miscarriage are bleeding and cramping. Bleeding alone is not necessarily a sign of impending miscarriage, and may be the result of a small area of bleeding behind the placenta. Indeed, between 20-25% of women who go on to have a healthy baby will have some bleeding in the first trimester.
In the event that miscarriage is suspected, two tests can be used to determine whether a woman is indeed having a miscarriage. The first test is pelvic ultrasound. A gestational sac will be present on ultrasound approximately 5 weeks after the last menstrual period, and an embryo can usually be seen after approximately 6 weeks. By 7 weeks a fetal heartbeat can be seen. Ultrasound may show an embryo that has died, or an empty gestational sac. Alternatively, the presence of a viable embryo with an appropriate heart rate raises the possibility that the pregnancy will survive.
The second test is a quanitative HCG test. In a healthy pregnancy, the HCG level should double approximately every 48 hours. If the level is not doubling appropriately, it can be a sign of impending miscarriage. Measuring the HCG level has the added advantage of providing information about pregnancies before they can be seen on ultrasound. Additionally, it provides information about the possibility of an ectopic pregnancy. This can be difficult to distinguish from an impending miscarriage.
In some cases a miscarriage will proceed spontaneously, resulting in the expulsion of all pregnancy tissue from the uterus. Often, though, the uterus is unable to expel all the tissue and the amount of bleeding and cramping can increase significantly. In these cases, a dilation and curretage is necessary.
Miscarriages occur more often than most people think. About 25% of women will experience one in their lives. Up to 78% of all conceptions may fail, in most cases before the woman even knows she is pregnant. A fifth of confirmed pregnancies have some bleeding occurring in the first 20 weeks and in all 15% proceed to miscarriage. After the age of 35, the risk of miscarriage increases considerably: 1 in 5 or 6. After 40, the risk increases to 1 in 3, and after 45 it is 1 in 2.
Forms and types
A threatened abortion is the development of symptoms (bleeding with or without cramps or low back pain) that often suggest impending miscarriage. With such a presentation of bleeding, 50% proceed to miscarriage of the pregnancy.
Management of these patients involves an examination to assess for cervical dilatation, an ultrasound to assess fetal viability, and bedrest for the mother, though there is no scientifically-proven benefit for the latter. When a threatened abortion occurs, no hormones or medications have been shown to prevent it.
The miscarriage of a pregnancy is inevitable when any of the following symptoms are present:
- There is an obvious rupture of membranes
- An open cervix
- There is tissue in the cervix
- There is an absence of fetal heart at a βHCG level consistent with fetal heart activity
When any of these symptoms are detected, management involves conservative observation, monitoring for heavy bleeding and sepsis, and a dilatation and curettage (D&C).
The infection of the womb carries risk of spreading infection (septicaemia) and is a grave risk to the life of the mother. It may follow an incomplete miscarriage and previously was a problem for pregnancies that occurred if a Dalkon Shield IUD had failed in its contraception. This has been particularly associated with abortions performed in non-sterile circumstances, common where abortions are carried out illegally and/or by poorly skilled and equipped operators.
A missed abortion is the miscarriage of a fetus in a pregnancy when the fetus has died, but remains in the uterus. Many cases of missed abortion will lead to a spontaneous abortion with days. Occasionally, a dilatation and currettage is necessary to remove the pregnancy tissue. That's because there is a risk of maternal coagulation abnormality if the tissue remains in the uterus for several weeks.
Habitual abortion (recurrent pregnancy loss or recurrent miscarriage) is the occurrence of 3 consecutive miscarriages. The majority (85%) of women who have had two miscarriages will conceive and carry normally afterwards, so statistically the occurrence of three abortions at 0.34%) is regarded as "habitual".
There are various medical conditions associated with this problem, some of which may be corrected with medication.
This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License
View live article