Every third woman will, on average, experience a miscarriage during her lifetime. Miscarriage means that the pregnancy is interrupted before the end of the 22nd pregnancy week. Most miscarriages occur, however, during early pregnancy.
About 10–5% of all pregnancies end with miscarriage before the 12th pregnancy week is full. Early miscarriages are apparently much more common than that. The embryo becomes implanted in the endometrium and forms placental tissue, which turns the pregnancy test from negative to positive, but after a few days there is a vaginal bleeding. The first stage of a miscarriage is marked by vaginal bleeding and abdominal pain. Many women, however, have not had any symptoms and hear for the first time about a miscarriage when attending for the screening ultrasound.
The reason for miscarriages remains usually unknown. Research has shown that more than half of the miscarriages are due to a chromosomal aberration of the fetus. The risk for such chromosomal aberrations tends to increase with the woman’s age. Miscarriages later in pregnancy may be due to structural aberrations of the uterus. Hormonal causes (like thyroid dysfunction) or asymptomatic celiac disease may lead to miscarriage. If miscarriages recur, the reason may be a familial disturbance in the coagulation system. This disturbance leads to functional disturbances of the placenta and late miscarriages.
It is not possible with medication or other means to halt the events leading to miscarriage once they have started. The miscarriage may be complete, but bleeding may continue for several days, even weeks. This needs often to be treated. Missed miscarriages are treated mainly with medication, usually at home. Such medication increases the uterine contractions which will expel the pregnancy tissue from the uterus together with some bleeding. Occasionally, medical treatment needs to be repeated. If medical evacuation is not successful, suction evacuation of then uterine cavity is performed as a hospital procedure. In late miscarriages, a dead fetus is born.
The purpose of examining miscarriages is to identify any risk factors and to get an impression of the likelihood of successful pregnancies after the miscarriage. Currently, the examinations cannot identify any reason in 50–75 % of cases. Of the hormonal reasons and risks, thyroid function and prolactin secretion should be assessed. Aberrant uterine structure can be assessed by ultrasound, complemented with hysterosonography, i.e., saline injection into the uterine cavity for studying the lining of the uterine cavity. If there is a suspicion of structural changes inside the uterus (e.g., polyp or a septum which partitions the uterus), hysteroscopy (taking a look into the uterine cavity) is performed which also allows the physician to treat abnormal findings. Of the familial blood coagulation disturbances, the most important examination is a blood test for phospholipid antibodies. Other tests that may be needed, depending on the individual situation, are celiac antibodies, antinuclear antibodies, chromosomal aberrations, vitamin D and homocysteine concentrations in the blood.
Causes for miscarriage related to the male partner are largely unknown. Excessive use of alcohol and smoking increase the risk for miscarriage. Especially if the couple experiences recurrent miscarriages, the DNA fragmentation test might help to identify the reason.
Since examinations only rarely identify the reason for miscarriage, it is not possible to prevent recurrences. If blood coagulation is disturbed, acetylsalicylic acid may be used, and from the beginning of pregnancy subcutaneous low-molecular weight heparin injections are often indicated. If the uterus has structural aberrations, uterine septums (partitions) an polyps may be corrected. It is always important to maintain good general health and to eat a healthy diet. No studies have shown that exercise, intercourse or lifting heavy burdens are associated with miscarriages.
A miscarriage is a heavy physical strain for the woman, but the mental suffering concerns both parts. When a crisis like miscarriage is encountered, it is essential that the woman is not abandoned; in this situation it would be overwhelming for the woman to take initiatives: the physical and mental resources are lacking. The treatment after miscarriage must focus on supporting empathically the couple in the midst of their grief and sorrow. The support provided by the family, the partner or a friend is extremely important and may suffice, but occasionally professional psychological support is needed and a psychologist can help the couple to overcome what has happened. This will provide relief and motivates continued efforts for the next pregnancy.
The prognosis for becoming pregnant is good. Even after three consecutive miscarriages, the next pregnancy will succeed for 60–80% of the women. Even now, psychological support is important. If the early pregnancy ultrasound shows that all is well, there will be much less concern and stress.