Miscarriage is the most common complication of early pregnancy. Sometimes called “spontaneous abortion,” miscarriages occur in 15 to 20 percent of all pregnancies. An estimated 80 percent of all miscarriages occur within the first 12 weeks of pregnancy.
Bleeding and strong cramping pain in the lower abdomen are common signs that a miscarriage may occur. You will want to contact your doctor immediately if you have a feeling that anything could be wrong.
In a majority of cases, the cause of miscarriage is not known. When it is known, it is caused by:
Chromosomes - In over 75 percent of early pregnancy miscarriages, the miscarriage is caused by a problem with the baby’s chromosomes—tiny structures inside each of your cells that carry genes, which will determine your baby’s physical traits. Problems with the structure of chromosomes and the number of genes they carry can result in the baby not being able to grow properly. Most of the time, these chromosomal problems are not inherited and occur by chance. Sometimes they are related to the mom’s advanced age. Healthy women over age 35 have an increased risk for miscarriage.
Pre-existing Illnesses - If you suffer from pre-existing illnesses—such as heart disease, uncontrolled diabetes, lupus and other autoimmune disorders, severe kidney disease linked with high blood pressure, thyroid disease, and polycystic ovary syndrome, you are at higher risk for miscarrying. Treating these illnesses before you get pregnancy can decrease your risk. Some illnesses may require special care, and you may have to be closely monitored during your pregnancy.
Hormonal Imbalance - Early in pregnancy, you can miscarry if you have low levels of progesterone in your body—the hormone that helps support the pregnancy to continue. Your obstetrician can administer vaginal suppositories of progesterone, but the benefits of this have not been established.
Uterine Problems - Problems with the shape of your uterus (an abnormally shaped uterus such as a heart-shaped uterus instead of a regular pear-shaped one) or cervix (an incompetent cervix) can lead to miscarriage. An incompetent cervix opens without contractions or any other sign of labor.
Substance Use - Smoking, heavy alcohol use, and illegal drug use during pregnancy can increase your risk of miscarriage. High levels of caffeine consumption have also been linked to an increased risk of miscarriage.
History of Miscarriages - Having a miscarriage in the past can increase your risk for future miscarriages.
Intrauterine Device - If you accidentally became pregnant using the intrauterine device (IUD), you have a very high risk of miscarriage (50 percent).
Antiphospholipid antibody syndrome - Women with autoimmune disorders, such as antiphospholipid antibody syndrome, are at increased risk of suffering a miscarriage. This is due to their immune system mistaking their unborn baby for a threat and attacking him or her.
Warning signs that a miscarriage may occur include spotting or bleeding that can be accompanied with pain; heavy or constant bleeding with abdominal pain or cramping; and vaginal discharge without pain or bleeding.
Having a miscarriage can be very distressing, but in most cases, you did not do anything to cause your miscarriage. There has been no evidence that working, exercising, continuing to have sex, or using birth control pills before getting pregnant increases your risk.
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