During the first 20 weeks of pregnancy, 20 to 30% of women have vaginal bleeding. In about half of these women, the pregnancy ends in a miscarriage. If miscarriage does not occur immediately, problems later in the pregnancy are more likely. For example, the baby's birth weight may be low, or the baby may be born early (preterm birth), be born dead (stillbirth), or die during or shortly after birth. If bleeding is profuse, blood pressure may become dangerously low, resulting in shock.

The amount of bleeding can range from spots of blood to a massive amount. Passing large amounts of blood is always a concern, but spotting or mild bleeding may also indicate a serious disorder.

Causes

Vaginal bleeding during early pregnancy may result from disorders related to the pregnancy (obstetric) or not (see Symptoms During Pregnancy: Some Causes and Features of Vaginal Bleeding During Early Pregnancy).

The most common cause is

• A miscarriage

There are different degrees of miscarriage (also called spontaneous abortion—see Complications of Pregnancy: Miscarriage). A miscarriage may be possible (threatened abortion) or certain to occur (inevitable abortion). All of the contents of the uterus (fetus and placenta) may be expelled (complete abortion) or not (incomplete abortion). The contents of the uterus may be infected before, during, or after the miscarriage (septic abortion). The fetus may die in the uterus and remain there (missed abortion). Any type of miscarriage can cause vaginal bleeding during early pregnancy.

The most dangerous cause of vaginal bleeding is

• Rupture of an abnormally located (ectopic) pregnancy―one that is not in its usual place in the uterus

Another possibly dangerous but less common cause is rupture of a corpus luteum cyst. After an egg is released, the structure that released it (the corpus luteum) may fill with fluid or blood instead of breaking down and disappearing as it usually does. If an ectopic pregnancy or a corpus luteum cyst ruptures, bleeding may be profuse, leading to shock.

Evaluation

Doctors first determine whether the cause is an ectopic pregnancy.

Warning signs: In pregnant women with vaginal bleeding during early pregnancy, the following symptoms are cause for concern:

• Fainting, light-headedness, or a racing heart—symptoms that suggest very low blood pressure
• Loss of large amounts of blood or blood that contains tissue or large clots
• Severe abdominal pain that worsens when the woman moves or changes positions
• Fever, chills, and a vaginal discharge that contains pus mixed with the blood

When to see a doctor: Women with warning signs should see a doctor immediately. Women without warning signs should see a doctor within 48 to 72 hours.

What the doctor does: Doctors ask about the symptoms and medical history (including past pregnancies, miscarriages, and abortions). Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause and the tests that may need to be done (see Symptoms During Pregnancy: Some Causes and Features of Vaginal Bleeding During Early Pregnancy ).

Doctors ask about the bleeding:

• How severe it is (for example, how many pads are used or soaked in an hour)
• Whether clots or tissue were passed
• Whether pain accompanies the bleeding

If pain is present, doctors ask when and how it started, where it occurs, how long it lasts, whether it is sharp or dull, and whether it is constant or comes and goes.

During the physical examination, doctors first check for fever and signs of substantial blood loss, such as a racing heart and low blood pressure. They then do a pelvic examination, checking to see whether the cervix (the lower part of the uterus) has started to open (dilate) to enable the baby to pass through. If any tissue (possibly from a miscarriage) is detected, it is removed and sent to a laboratory to be analyzed.

Doctors also gently press on the abdomen to see whether it is tender when touched.

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Some Causes and Features of Vaginal Bleeding During Early Pregnancy Cause Common Features* Tests† Pregnancy-related (obstetric) disorders An ectopic pregnancy (an abnormally located pregnancy—not in its usual place in the uterus) Sometimes only slight vaginal bleeding Abdominal or pelvic pain that Is often sudden and constant (not crampy) Begins in a specific spot Is sometimes slight Usually tenderness when the pelvic examination is done If the ectopic pregnancy has ruptured, fainting, light-headedness, or a racing heart Usually blood tests to measure a hormone produced by the placenta (human chorionic gonadotropin, or hCG) Ultrasonography of the pelvis Sometimes laparoscopy (insertion of a viewing tube through an incision in the abdomen) or laparotomy (surgery involving an incision into the abdomen) A miscarriage that Has occurred or is occurring May occur (threatened abortion) Crampy pain in the pelvis and often throughout the abdomen Often vaginal bleeding, sometimes with passage of tissue from the fetus Tests as for ectopic pregnancy Septic abortion (infection of the contents of the uterus) Fever and chills, constant abdominal pain, vaginal discharge that contains pus Usually in women who have had an intentional abortion (often done by untrained practitioners or by the women themselves) Cultures of samples taken from the cervix A hydatidiform mole (overgrowth of tissue from the placenta) or another form of gestational trophoblastic disease A uterus that is larger than expected No heartbeat or movement detected in the fetus Sometimes high blood pressure, swelling of the feet or hands, severe vomiting, or passage of tissue that resembles a bunch of grapes Tests as for ectopic pregnancy A biopsy Rupture of a corpus luteum cyst (which develops in the structure that releases the egg after the egg is released) Abdominal or pelvic pain that Begins in a specific spot Sometimes causes nausea and vomiting Usually begins suddenly Most common during the first 12 weeks of pregnancy Ultrasonography of the pelvis Disorders unrelated to the pregnancy Vaginitis (inflammation of the vagina, often due to infection) Only spotting or slight bleeding A vaginal discharge Sometimes pain during sexual intercourse, pelvic pain, or both A doctor's examination to rule out other causes Cultures of samples taken from the cervix Cervicitis (infection of the cervix) Only spotting or slight bleeding Sometimes tenderness when the pelvic examination is done, abdominal pain, or both A doctor's examination to rule out other causes Cultures of samples taken from the cervix Polyps (fingerlike growths) in the cervix, which are usually benign Slight bleeding No pain Polyps sometimes seen protruding from cervix A doctor's examination Follow-up visits to further evaluate the polyps *Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present. †A urine pregnancy test is typically done if women have had only a home pregnancy test. Because an ectopic pregnancy can be very dangerous, tests are done to look for ectopic pregnancy in most pregnant women with vaginal bleeding unless symptoms clearly point to another disorder.

Testing: During the examination, doctors may use a handheld Doppler ultrasound device, placed on the woman's abdomen, to check for a heartbeat in the fetus.

If pregnancy has not been confirmed by a health care practitioner, a pregnancy test using a urine sample is done. Once pregnancy is confirmed, several tests are done:

• Blood type and Rh status (positive or negative)
• Usually ultrasonography
• Usually blood tests to measure a hormone produced by the placenta during early pregnancy (human chorionic gonadotropin, or hCG)

Rh status is determined because a pregnant woman with Rh-negative blood must be treated with Rh₀(D) immune globulin if she has any vaginal bleeding. Treatment is needed to prevent her from producing antibodies that may attack the fetus's red blood cells in subsequent pregnancies (see Complications of Pregnancy: Rh Incompatibility). If bleeding is substantial (more than about a cup), doctors also do a complete blood cell count (CBC) and tests to check for abnormal antibodies or to cross-match blood (to determine whether the woman's blood type is compatible with a donor's). If blood loss is substantial or shock develops, tests are done to determine whether blood can clot normally.

Typically, ultrasonography is done using an ultrasound device inserted into the vagina unless the examination indicated that a complete miscarriage occurred. Ultrasonography can detect a pregnancy in the uterus and can detect a heartbeat after about 6 weeks of pregnancy. If no heartbeat is detected after this time, miscarriage is inevitable. If a heartbeat is detected, miscarriage is much less likely but may still occur. Ultrasonography can also help identify a miscarriage that is incomplete, is infected, or has been missed. It can detect any parts of the placenta or other pregnancy-related tissues that remain in the uterus. Ultrasonography can help identify a ruptured corpus luteum cyst and a hydatidiform mole or other forms of gestational trophoblastic disease. Sometimes ultrasonography can detect an ectopic pregnancy, depending on where it is located and how big it is.

Measuring hCG levels helps doctors interpret ultrasonography results and distinguish a normal pregnancy from an ectopic pregnancy. If the likelihood of an ectopic pregnancy is low, hCG levels are measured periodically. If the likelihood is moderate or high, doctors may make a small incision just below the navel and insert a viewing tube (laparoscope) to directly view the uterus and surrounding structures (laparoscopy) and thus determine whether an ectopic pregnancy is present.

Treatment

If bleeding is profuse, if shock develops, or if a ruptured ectopic pregnancy is likely, one of the first things doctors do is to place a large catheter in a vein so that blood can be quickly given intravenously.

When bleeding results from a disorder, that disorder is treated if possible. For example, surgery is done when an ectopic pregnancy has ruptured.

Although doctors have typically recommended bed rest when a miscarriage seems possible, there is no evidence that bed rest helps prevent miscarriage. Refraining from sexual intercourse is advised, although intercourse has not been definitely connected with miscarriages.

Key Points

• The most common cause of bleeding during early pregnancy is a miscarriage.
• The most serious cause of vaginal bleeding is an ectopic pregnancy.
• A pregnant woman should see a doctor immediately if she has a racing heart, faints, or feels faint.
• Blood tests to determine whether blood is Rh-negative or Rh-positive are done because if a pregnant woman with Rh-negative blood has vaginal bleeding, she must be given Rh₀(D) immune globulin to prevent her from producing antibodies that may attack the fetus's red blood cells in subsequent pregnancies.

Last full review/revision May 2012 by R. Phillips Heine, MD; R. Phillips Heine, MD