An estimated 15 to 20 percent of known pregnancies end in miscarriage, the loss of a pregnancy before the twentieth week. (The actual number is likely higher, because many miscarriages occur very early on, before a woman knows she is pregnant, and may simply seem to be a heavy period on or near schedule.)
Most clinically recognized miscarriages occur between the seventh and twelfth week after a woman’s last menstrual period. The chances of miscarriage decrease significantly once a heartbeat has been detected on ultrasound or by Doppler stethoscope.
The vast majority of miscarriages (also called spontaneous abortions) cannot be prevented; they are random events that are not likely to recur. Up to 70 percent of first-trimester miscarriages, and 20 percent of second-trimester miscarriages, are caused by chromosomal anomalies. Other known causes include infection, abnormalities of the uterus or cervix, smoking, substance abuse, exposure to environmental or industrial toxins, diabetes, thyroid disease, and autoimmune disease.
Older women are more likely to miscarry than younger women are. Serious physical trauma can also cause a miscarriage. In rare cases, women miscarry after diagnostic tests, such as chorionic villus sampling (CVS) or amniocentesis. Most of the time, a specific cause for miscarriage is not identified.
Many women learn about a miscarriage at a routine prenatal visit before experiencing any physical symptoms. Sometimes no embryo is seen on ultrasound, or the embryo may be much smaller than expected, or without a heartbeat. The first symptoms of miscarriage are usually spotting or bleeding, followed by cramps in your lower back or abdomen. Other signs include fluid or tissue passing from the vagina.
About one in four women experience some vaginal bleeding or spotting during their first trimester. If the bleeding is light and lasts only 1 to 2 days, it isn’t associated with a greater risk of miscarriage. However, heavy bleeding is associated with miscarriage; about one in four women who experience heavy bleeding will go on to miscarry. If you have any vaginal bleeding during pregnancy, your health care provider can help determine if the bleeding is likely to result in miscarriage.
If you are miscarrying, bleeding will become heavier and cramping can be painful as the cervix dilates. Ectopic (tubal) pregnancy can cause bleeding and pain, so if you have severe pain or risk factors for ectopic like a previous ectopic, current IUD use, prior pelvic infection or infertility, be sure to seek medical care right away. Ectopic pregnancy is a medical emergency because of the risk of internal bleeding.
If a blood test or sonogram indicates that you are having a miscarriage, you may have a few options. Some women choose to allow the miscarriage to occur and complete itself naturally. Others find that scheduling a procedure to empty the uterus provides a sense of control and closure; it also decreases the risk of infection and excessive bleeding.
There are several different treatments to complete the miscarriage. In early pregnancy you can take a drug, such as misoprostol, that causes uterine contractions and miscarriage. Or a minor surgical procedure (suction curettage, also known as dilation and curettage, or D&C) uses an aspiration technique to remove any remaining tissue. Both of these are outpatient procedures. Aspiration may be performed on an outpatient basis in a clinic, obstetrical office, hospital, or emergency room, with or without anesthesia.
If you do not know your blood type, you should have a blood test. If your blood type is Rh-negative, you will need a shot within seventy-two hours of the miscarriage. (If you are Rh-negative and you were carrying an Rh-positive fetus, there is a small chance that you have been exposed to Rh-positive blood cells from the fetal tissue during the miscarriage. A shot of RhoGAM prevents your body from producing antibodies to Rh-positive blood that could harm a fetus during a future pregnancy.)
If you miscarry naturally or with medication, you will probably complete the miscarriage at home. The process may be over quickly or may take several days. If you are less than 8 weeks pregnant when the miscarriage occurs, the expelled tissue will look no different from heavy menstrual bleeding. The further along you are in pregnancy, the heavier the bleeding and more severe the cramps. You may see the fetus and placenta.
Try to arrange for a trusted, knowledgeable person to be with you through the process, throughout the night if needed. Think about where you will be most comfortable and what you will need, such as bed liners and sanitary pads, or hot water bottles and massage to comfort you and help with cramping. Your care provider may offer you pain medication to help you get through.
You may want to think and talk about what you would like to do with the remains. There will be some blood clots, and you may notice tissue that is firmer or lumpy-looking, which is placental or afterbirth tissue. You may or may not see tissue that looks like an embryo or fetus. If this is a recurrent (not first) miscarriage, you may want to save the tissue for testing.
Once everything in your uterus has been expelled, bleeding will continue, lessening over several days. If bleeding increases or stays bright red, or if you have foul-smelling discharge or a fever or persistent cramping, contact your health care provider. If pregnancy tissue remains in your uterus, your provider can perform a D&C to remove it and thereby prevent infection. A D&C involves dilating the cervix and using suction (aspiration) and/or a medical instrument called a curette to remove remaining pregnancy tissue.
Once bleeding has ceased and the cervix is closed, you can have sex (including penetration) without excess risk of infection. Since it is difficult to know when the cervix has completely closed, most providers recommend waiting two weeks. A repeat pregnancy test after a few weeks is important to make sure your pregnancy hormone levels have returned to normal. If you feel dizzy or tired, tell you healthcare provider so you can be checked for anemia.
First trimester miscarriage is most likely a random event, unlikely to recur. If you have had two or more earlier miscarriages, medical tests to help identify the cause are recommended. If you are at home when you miscarry, you may be able to collect fetal or afterbirth tissue in a clean container for examination at a hospital-based laboratory. Put the tissue in a clean glass jar and refrigerate until you can bring it to your care provider for testing. Ask to see the pathology report, and ask for a full explanation of all terminology.
Blood tests on the parents may identify or rule out hormonal, immunological, or chromosomal abnormalities. Examinations of the uterus by ultrasound, hysteroscopy, hysterosalpingography, and/or an endometrial biopsy may also provide important information. Even if the cause cannot be determined after testing — which is often the case — you will gain knowledge. You may be able to rule out likely causes of a repeat miscarriage and at least know that you have done all you can to get an answer.
Physical recovery from a miscarriage ranges from a few days to a couple of weeks. Your period will return within four to eight weeks. Emotional recovery is likely to take longer. Give yourself time to grieve, search for medical explanations if there are any, and seek out other women who have miscarried.