Miscarriage is the loss of a pregnancy, or expulsion of a fetus before it is sufficiently developed to survive. The term "miscarriage" is strictly a popular or lay term. Physicians typically use "abortion," distinguishing only between spontaneous or natural abortion, which occurs through natural causes, and induced, elective or therapeutic abortion, which results from artificial intervention.
A miscarriage is the ending of a pregnancy due to the premature delivery of the fetus before the twentieth (20th) week of pregnancy. At that point, the fetus is not developed enough to survive outside the uterus on its own. After the twentieth week of pregnancy, a spontaneous abortion is considered a premature delivery or, if the fetus is dead at delivery, a stillbirth.
Types Of Miscarriage
Threatened Miscarriage. Symptoms indicating that a pregnancy may end prematurely, most often consist of slight bleeding and mild cramps.
Bleeding alone need not be a sign of threatened miscarriage. If the bleeding continues for a time, however, it is advisable to check for a cause other than threatened miscarriage, such as a cervical polyp. Ultrasound can determine if the fetus is alive, as can a blood test for HCG (human chorionic gonadotropin), whose levels should be increasing.
Bleeding and cramps together nearly always constitute a threatened miscarriage, although the cramps are usually not strong enough to dilate the cervix. When they are, miscarriage is usually inevitable.
- Inevitable Miscarriage. This is the occurrence of severe vaginal bleeding and/or cramps in a pregnant woman, indicating that no medical treatment can avert a miscarriage. At this point, the amniotic membranes have ruptured, the cervix is dilated, and the membranes, fetus and placenta are on their way to being expelled. The woman's clinician should be contacted immediately, and hospitalization may be necessary.
- Incomplete Miscarriage. A miscarriage in which not all of the products of conception - membranes, placenta, fetus, are spontaneously expelled. Most often it is the placenta that is retained. Sometime a drug such as oxytocin is administered to stimulate uterine contractions that may expel the remainder, but more often a D & C (dilatation and curettage) or vacuum aspiration is performed to make sure all of the tissue is out of the uterus to prevent infection and more blood loss.
An estimated 15 to 20 percent of all known pregnancies in North America end in miscarriage. In underdeveloped countries the rate is much higher. The majority occur during the first three months of pregnancy. More than 60 percent of spontaneous abortions result from chromosomal defects in the fetus due to maternal or paternal factors.
Apart from abnormal fetal development, a number of other factors can contribute to a miscarriage. These may include abnormalities in the father's sperm; abnormalities in the egg; disease in the mother (for example, an infection, a glandular disorder, high blood pressure, kidney or heart disease, or diabetes); uterine abnormalities; the mother's poor nutrition or use of cigarettes, alcohol, or drugs; and exposure to pollutants.
There is no evidence that video display terminals or associated electromagnetic fields are related to an increased risk of spontaneous abortion.
The mother's jumping, vigorous physical exercise, or frequent vaginal intercourse do not cause miscarriage.
In about 25 percent of cases, the cause of abortion cannot be determined.
The bleeding that occurs in abortion of a uterine pregnancy must be differentiated from the abnormal bleeding of an ectopic (outside of the uterus) pregnancy and abnormal bleeding in a non-pregnant women.
A medical history, physical exam, laboratory tests including a quantitative HCG pregnancy test, and ultrasound study are suggested.
There is no medical treatment to stop or prevent an inevitable miscarriage. The physician generally directs the woman with symptoms to rest in bed and abstain from sexual intercourse and douching. As noted above, in the case of incomplete abortion, prompt surgical removal of any products of conception is required.
It is normal for a woman to feel depressed by the loss of an expected child and counseling may be very helpful. On the advice of her physician, it is usually safe for her to attempt to conceive a soon time afterward (six to eight weeks later).