What Is A Threatened Miscarriage? Causes, Symptoms And Risk Factors

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Vaginal bleeding in the first 20 weeks or first three months of pregnancy is known as a threatened miscarriage or threatened abortion. Some women may undergo a healthy pregnancy after a threatened abortion, whereas others may have a miscarriage.

You may require a healthcare provider’s attention during threatened miscarriage to identify the cause and to establish a management plan.

Read this post to know more about the causes, signs, symptoms, complications, risk factors, and management of a threatened abortion.

Causes Of Threatened Abortion

The common causes of a threatened miscarriage,which is vaginal bleeding, may include (1) (2):

  • Infections
  • Miscarriage
  • Molar pregnancy
  • Chronic illnesses, such as diabetes, high blood pressure,and thyroid problems
  • Alcohol use
  • Recreational drug use
  • Uterine factors – septum, fibroids, polyps
  • Cervix is incompetent and cannot hold the pregnancy
  • Genetic causes like abnormal embryo
  • Immunological cause

Early pregnancy bleeding can be due to minor issues in the uterus, cervix, vagina, or the external genitalia. It can often be due to implantation or irritation that may occur after sexual intercourse.

Fetal problems such as chromosomal abnormalities may cause threatened miscarriage or miscarriage in the first trimester (first three months) of pregnancy. In contrast, second-trimester miscarriages can be due to maternal factors such as diabetes, hypertension, ibroids malformation of uterus, etc.

Symptoms And Signs Of Threatened Abortion

Vaginal bleeding is the main symptom of threatened miscarriage, and it can be light or heavy bleeding. Some women may experience cramping or abdominal pain, along with bleeding (2).

You may have light spotting or heavy blood loss, blood clots, and may feel pain in the pelvis or lower back.

Duration of vaginal bleeding during threatened miscarriage may vary in each pregnant woman,depending on the causing factor.You may contact your doctor if you are experiencing vaginal bleeding during pregnancy, even if light or without belly pain.

Risk Factors Of Threatened Miscarriage

The risk factors for threatened miscarriage can be high in the following situations (2).

  • Presence of infections
  • History of trauma
  • Usage of certain medications
  • Advanced maternal age
  • Previous history of abortions

In case of high fever or other illnesses, you may seek medical care during pregnancy. Always take medications and supplements that are safe during pregnancy.

Complications Of Threatened Abortion

Possible complications of threatened abortion may include the following (3).

  • Moderate and heavy bleeding may result in anemia
  • Increased risk for infections
  • May result in miscarriage

The complications may vary depending on the causes.

When To Call A Doctor For A Threatened Miscarriage?

You may seek medical care if you are having any symptoms of threatened miscarriage. Early diagnosis and treatment may give better outcomes.

It is recommended to seek your doctor’s advice and have prescription medication for any health concerns or illnesses during pregnancy.

How Is A Threatened Miscarriage Diagnosed?

Your doctor may diagnose threatened abortion based on your symptoms and medical history, along with physical examination (pelvic exam) to confirm vaginal bleeding. The following tests can be ordered for a detailed analysis of fetus and maternal status (4).

  • Blood tests: These may help identify the levels of pregnancy hormone, human choriogonadotropin (hCG), and any anemia or B sugar . It may also help determine the blood type and administer RhoGAM medicine to prevent blood interaction with the fetus if you are RH negative with a partner who is RH positive blood type.
  • Urine tests: Urinalysis is often helpful in identifying urinary tract infections (UTIs) or asymptomatic bacteriuria (bacteria in the urine).
  • Ultrasound: Ultrasound of pelvis can be done to look at the fetus and placenta. It may help assess the presence of fetus, location of pregnancy (ectopic pregnancy), and any other abnormalities.
  • Fetal heart monitoring: Fetal heart rate is seen.

Your doctor may also order a few other tests based on your health status and cause of threatened miscarriage.

Threatened Miscarriage Treatment

Many pregnant women can get well without any treatment if they have light spotting or not lasting bleeding. However, a few pregnant women may require some interventions to continue the pregnancy. This may include (4):

  • Medications, such as progesterone hormones given to continue the pregnancy. This female hormone supports a pregnancy.
  • Rho immune globulin, which is given if the mother has Rh-negative blood type and prevents interaction with fetal blood through the formation of antibodies against fetal blood.
  • Bed rest and minimal activity, along with medications, in case of heavy bleeding.
  • Fluid and electrolyte replacement by intravenous fluids or blood transfusion, sometimes required in severe blood loss and dehydration.
  • Antibiotics prescribed to treat bacterial infection.
  • Control of Maternal diabetes, hypertension, and hypothyroidism
  • Pain medications, if required.

It is essential to seek medical care to safeguard your pregnancy in a threatened miscarriage. Your doctor can identify the cause and give relevant treatment to manage the condition.

Is A Surgery Required For Threatened Miscarriage?

Not all women who undergo threatened abortion require surgical procedures. If there is cervical incompetence (weakness of cervix), then cervical cerclage (cervical stitch) is done. This is usually done in the second trimester of pregnancy.

Note: Dilation and curettage (D & C) procedures are done after the miscarriage to clear any remaining products of conception in the uterus (5). This may often be delayed in the presence of pelvic infection and contraindicated in clotting disorders and other medical problems.

What Is The Long-term Outlook?

The prognosis of threatened abortion may vary based on maternal and fetal health status and etiologic factors (causes).

More than 50% of threatened abortion or vaginal bleeding occurs in the first 12 weeks of gestation, but most women continue to have a healthy pregnancy (4). However, others can have continued bleeding that may often end in a miscarriage.

Pregnant women with threatened miscarriage have an increased risk of miscarriage than others. Seek medical care if you have any vaginal bleeding or discomfort during pregnancy.

Prevention Of Threatened Miscarriage

Prevention of threatened miscarriage may not be possible in all cases. However, proper prenatal care could reduce the risk (3).

Proper management of diabetes and hypertension (high blood pressure) during pregnancy and early treatment of infections can be helpful. You should also avoid recreational drugs, over-the-counter medications, smoking, and alcohol during pregnancy since these may lead to bleeding and other complications.

You may also take recommended vitamin and mineral supplements, such as iron supplement or folic acid supplement, as per the gynecologist’s prescription to reduce the risk of miscarriage and to promote a baby’s health.

What Should You Do After A Threatened Miscarriage?

If you experience threatened miscarriage or miscarriage, then the first thing to do is to seek medical care. The below-listed suggestions can be followed after a miscarriage (6).

  • Take rest to feel better
  • Do not insert tampons into the vagina
  • Do not douche vagina with chemicals or any other products
  • Avoid sexual intercourse until you are well
  • Visit the emergency room if you have a high fever, cramping, heavy bleeding, or miscarriage.

Always seek medical help if you have any alarming signs or symptoms while pregnant. You may also do follow-up visits and tests to ensure your and your baby’s health status after threatened abortion.The chances of continuation of a healthy pregnancy may vary in each woman, depending on the causative factors and prenatal care.


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1. Spontaneous abortion; MSD manual
2. Threatened Miscarriage;  Beth Israel Lahey Health; Winchester Hospital
3. Miscarriage – threatened; MedlinePlus; The United States National Library of Medicine
4. Michelle Mouri and Timothy J. Rupp.; Threatened Abortion; The United States National Library of Medicine
Dialatation & Curettage (D&C); St. Clair Health
6. I Szabo and A Szilagyil; Management of Threatened Abortion; The United States National Library of Medicine