Understanding Miscarriage

Loss of pregnancy in the first 20 weeks of pregnancy occurs in about 10% to 20% of pregnancies, most often in the first trimester (first 13 weeks of pregnancy). At Hoag, we understand that a miscarriage is a significant loss to you and your family. We are here to help you to grieve – and to better understand – your loss. Visit our pregnancy and infant loss program page for resources.


About half of early pregnancy losses are from chromosome defects in the embryo or fetus. Other causes may include:

  • abnormal embryo development
  • hormone problems in the pregnant person
  • diabetes in the pregnant person, especially poorly controlled blood sugar
  • uterine issues, including scar tissue or fibroids.
  • incompetent cervix, or the inability of the cervix to stay closed during pregnancy.
  • infection or autoimmune diseases
  • injury or trauma
  • exposure to toxic substances (i.e., chemotherapy)

Genetic testing on the miscarried fetus can sometimes offer clues about the cause of miscarriage, but more often the cause cannot be found.


Vaginal bleeding is the most common symptom of miscarriage. While spotting or small amounts of bleeding during the first trimester are common, you will want to work with your obstetrician if you notice any bleeding, particularly if it is accompanied by back pain or abdominal cramping.

Your doctor will likely use ultrasound to diagnose miscarriage. Other tests include blood tests for the hormone human chorionic gonadotropin (hCG). Lower than normal levels of this hormone or levels may mean the pregnancy is not progressing properly.


If lab tests and ultrasound show that the pregnancy is progressing well, your doctor may prescribe bed rest and continue to monitor you and your baby.

However, if tests show that you have had a miscarriage in the first trimester, you can talk with your doctor about your options, including:

  • Expectant management, or waiting for the miscarriage to happen on its own. Your doctor will monitor you often during this time.
  • Medical management, or the use of misoprostol to make the uterus contract and push out the pregnancy tissues.
  • Surgical management to remove the fetus and other tissues if they haven’t all been naturally passed. The procedure is called a surgical evacuation of the uterus, or a dilation and curettage (D&C). You will be given anesthesia before the cervical opening is stretched open (dilated). Your doctor will then use either suction or a tool called a curette to remove all the pregnancy tissues inside the uterus.

Pregnancy loss after 20 weeks may require medicines such as misoprostol or prostaglandin to help open the cervix and cause the uterus to contract and push out the fetus and tissues.

Miscarriage doesn’t often cause other serious health problems, but infection is possible if tissues aren’t passed. Blood clotting issues could also arise if it takes a month or longer for the tissue to pass.

People with Rh negative blood may need treatment with a medicine called Rh immunoglobulin after a miscarriage to prevent problems with blood incompatibility in a future pregnancy.

Risk factors

While many women experience miscarriage, some factors can increase your risk, including:

  • pregnancy at an older age
  • past early pregnancy loss
  • smoking
  • excessive alcohol consumption
  • drinking more caffeine
  • cocaine use
  • low folate levels.
  • the use of NSAIDs (nonsteroidal anti-inflammatory drugs) around the time of conception
  • uterine issues, including fibroids.
  • certain conditions such as celiac disease, high blood pressure, thyroid disease, or diabetes
  • serious infection or major injury

Call your doctor immediately if you have any bleeding, cramping or other symptoms during pregnancy. You will be connected to the resources you need. At Hoag, we are here with you every step of the way.