Table: Some Causes and Features of Vaginal Bleeding During Late Pregnancy-Merck Manual Consumer Version

Some Causes and Features of Vaginal Bleeding During Late Pregnancy

Cause	Common Features*	Diagnostic Approach†,‡
Labor	Begins with passage of a small amount of blood, sometimes mixed with mucus (mucus plug or bloody show) Uterine contractions at regular intervals plus opening (dilation) and thinning and pulling back (effacement) of the cervix	Pelvic examination and monitoring of woman's vital signs Fetal heart rate monitoring
Placental abruption (premature detachment of the placenta from the uterus)	Pain or tenderness when the uterus is touched Passage of dark, clotted, or bright red blood that can be light or heavy bleeding Sometimes low blood pressure in the woman, with fainting, light-headedness, or a rapid heart rate Sometimes an abnormal heart rate in the fetus	Pelvic examination and monitoring of woman's vital signs Fetal heart rate monitoring Complete blood cell count and blood tests to determine whether blood is clotting normally Often ultrasonography
Placenta previa (an abnormally located placenta)	Painless vaginal bleeding Little or no tenderness when the uterus is touched Often, a low-lying placenta detected earlier in pregnancy on ultrasonography	Complete blood count Ultrasonography
Vasa previa (growth of the fetus’s blood vessels across the cervix, blocking the fetus's passageway)	Painless vaginal bleeding Often signs of labor, such as contractions at regular intervals An abnormal heart rate in the fetus Sometimes, suspected based on findings during routine screening ultrasonography	Transvaginal ultrasonography using techniques to show blood flow (color Doppler ultrasonography)
Uterine rupture	Severe abdominal pain and tenderness when the abdomen is touched Stopping of contractions and often loss of muscle tone in the uterus Baby moves back up into the birth canal Slight to moderate vaginal bleeding A slow heart rate in the fetus or no heartbeat A rapid heart rate in the woman Usually, a history of prior cesarean delivery or other uterine surgery	The doctor's suspicion, based on characteristic symptoms Emergency cesarean delivery
* Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present.
† In pregnant women with concerning symptoms, the doctor assesses maternal vital signs, does a physical examination, and evaluates the fetus with a fetal heart rate monitor or ultrasonography.
‡ Ultrasonography is typically done in women with bleeding late in pregnancy, and a complete blood cell count, blood type, and Rh status (positive or negative) are usually determined.

Cause

Common Features*

Diagnostic Approach†,‡

Begins with passage of a small amount of blood, sometimes mixed with mucus (mucus plug or bloody show)

Uterine contractions at regular intervals plus opening (dilation) and thinning and pulling back (effacement) of the cervix

Pelvic examination and monitoring of woman's vital signs

Fetal heart rate monitoring

Placental abruption (premature detachment of the placenta from the uterus)

Pain or tenderness when the uterus is touched

Passage of dark, clotted, or bright red blood that can be light or heavy bleeding

Sometimes low blood pressure in the woman, with fainting, light-headedness, or a rapid heart rate

Sometimes an abnormal heart rate in the fetus

Pelvic examination and monitoring of woman's vital signs

Fetal heart rate monitoring

Complete blood cell count and blood tests to determine whether blood is clotting normally

Often ultrasonography

Placenta previa (an abnormally located placenta)

Painless vaginal bleeding

Little or no tenderness when the uterus is touched

Often, a low-lying placenta detected earlier in pregnancy on ultrasonography

Complete blood count

Ultrasonography

Vasa previa (growth of the fetus’s blood vessels across the cervix, blocking the fetus's passageway)

Painless vaginal bleeding

Often signs of labor, such as contractions at regular intervals

An abnormal heart rate in the fetus

Sometimes, suspected based on findings during routine screening ultrasonography

Transvaginal ultrasonography using techniques to show blood flow (color Doppler ultrasonography)

Uterine rupture

Severe abdominal pain and tenderness when the abdomen is touched

Stopping of contractions and often loss of muscle tone in the uterus

Baby moves back up into the birth canal

Slight to moderate vaginal bleeding

A slow heart rate in the fetus or no heartbeat

A rapid heart rate in the woman

Usually, a history of prior cesarean delivery or other uterine surgery

The doctor's suspicion, based on characteristic symptoms

Emergency cesarean delivery

* Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present.

† In pregnant women with concerning symptoms, the doctor assesses maternal vital signs, does a physical examination, and evaluates the fetus with a fetal heart rate monitor or ultrasonography.

‡ Ultrasonography is typically done in women with bleeding late in pregnancy, and a complete blood cell count, blood type, and Rh status (positive or negative) are usually determined.