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 Miscarriage A miscarriage is the loss of a fetus before 20 weeks of pregnancy. Miscarriages may occur because of a problem in the fetus (such as a genetic disorder or birth defect) or in the woman (such... read more . If miscarriage does not occur immediately, problems later in the pregnancy are possible. For example, the baby's birth weight may be low, or the baby may be born early (preterm birth Preterm Labor Labor that occurs before 37 weeks of pregnancy is considered preterm. Babies born prematurely can have serious health problems. The diagnosis of preterm labor is usually obvious. Measures such... read more ), be born dead (stillbirth Stillbirth Stillbirth is death of a fetus after 20 weeks of pregnancy. Stillbirth may result from a problem in the woman, placenta, or fetus. Doctors do blood tests to try to identify the cause of a stillbirth... read more ), or die during or shortly after birth. If bleeding is profuse, blood pressure may become dangerously low, resulting in shock Shock Shock is a life-threatening condition in which blood flow to the organs is low, decreasing delivery of oxygen and thus causing organ damage and sometimes death. Blood pressure is usually low... read more . However, many women with light bleeding in early pregnancy go on to have a healthy pregnancy and delivery.
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 table Some Causes and Features of Vaginal Bleeding During Early Pregnancy Some Causes and Features of Vaginal Bleeding During Early Pregnancy 
).
The most common cause of vaginal bleeding during early pregnancy is
There are different degrees of miscarriage Miscarriage A miscarriage is the loss of a fetus before 20 weeks of pregnancy. Miscarriages may occur because of a problem in the fetus (such as a genetic disorder or birth defect) or in the woman (such... read more (also called spontaneous abortion). 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 during early pregnancy is
Rupture of an abnormally located pregnancy (ectopic pregnancy Ectopic Pregnancy Ectopic pregnancy is attachment (implantation) of a fertilized egg in an abnormal location, such as the fallopian tubes. In an ectopic pregnancy, the fetus cannot survive. When an ectopic pregnancy... read more )—one that is not in its usual place in the uterus—for example, one that is in a fallopian tube
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.
Risk factors
For miscarriage, risk factors include the following:
Age over 35
One or more miscarriages in previous pregnancies
Use of drugs such as cocaine Cocaine during pregnancy More than 50% of pregnant women take prescription or nonprescription (over-the-counter) drugs or use social drugs (such as tobacco and alcohol) or illicit drugs at some time during pregnancy... read more , alcohol Alcohol during pregnancy More than 50% of pregnant women take prescription or nonprescription (over-the-counter) drugs or use social drugs (such as tobacco and alcohol) or illicit drugs at some time during pregnancy... read more , or consumption of a lot of caffeine Alcohol during pregnancy More than 50% of pregnant women take prescription or nonprescription (over-the-counter) drugs or use social drugs (such as tobacco and alcohol) or illicit drugs at some time during pregnancy... read more
Abnormalities in the uterus, such as fibroids Stones in the Urinary Tract Stones (calculi) are hard masses that form in the urinary tract and may cause pain, bleeding, or an infection or block of the flow of urine. Tiny stones may cause no symptoms, but larger stones... read more
, scarring, or an abnormal shape of the uterusPoorly controlled medical disorders such as diabetes, thyroid disease, or lupus
For ectopic pregnancy, risk factors include
A previous ectopic pregnancy (the most important risk factor)
Previous abdominal surgery, especially for permanent sterilization (tubal ligation)
A previous infection with a sexually transmitted infection Overview of Sexually Transmitted Infections (STIs) Sexually transmitted infection (STI) refers to an infection that is passed through blood, semen, vaginal fluids, or other body fluids during oral, anal, or genital sex with an infected partner... read more
or pelvic inflammatory disease Pelvic Inflammatory Disease (PID) Pelvic inflammatory disease is an infection of the upper female reproductive organs (the cervix, uterus, fallopian tubes, and ovaries). Pelvic inflammatory disease is often caused by a sexually... read more 
Cigarette smoking
Age over 35
A history of infertility Overview of Infertility Infertility is usually defined as the inability to achieve a pregnancy after 1 year of regular sexual intercourse without birth control. Frequent intercourse without birth control usually results... read more
, use of fertility drugs Treatment Women may have infertility if the ovaries do not release an egg each month, as usually occurs during a menstrual cycle. Ovulation problems can result from dysfunction of the part of the brain... read more , or use of assisted reproductive techniques Assisted Reproductive Technologies Assisted reproductive technologies involve working with sperm and eggs or embryos in a laboratory (in vitro) with the goal of producing a pregnancy. (See also Overview of Infertility.) If treatment... read more 
(in vitro fertilization)Several sex partners
Vaginal douching
Evaluation
Doctors first determine whether the cause of vaginal bleeding 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 Vaginal Discharge A discharge from the vagina may occur normally or may result from inflammation of the vagina (vaginitis), often due to an infection. The genital area (vulva)—the area around the opening of the... read more
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, abortions, and risk factors for ectopic pregnancy and miscarriage). 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 table Some Causes and Features of Vaginal Bleeding During Early 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 Pelvic Examination For gynecologic care, a woman should choose a health care practitioner with whom she can comfortably discuss sensitive topics, such as sex, birth control, pregnancy, and problems related to... read more , checking to see whether the cervix (the lower part of the uterus) has started to open (dilate) to enable the pregnancy 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.
Testing
During the examination, doctors may use a handheld Doppler ultrasound device Doppler ultrasonography Ultrasonography uses high-frequency sound (ultrasound) waves to produce images of internal organs and other tissues. A device called a transducer converts electrical current into sound waves... read more 
, placed on the woman's abdomen, to check for a heartbeat in the fetus.
If a home pregnancy test indicates pregnancy but pregnancy has not been confirmed by a health care practitioner, doctors do a pregnancy test using a urine sample.
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 (human chorionic gonadotropin, or hCG) produced by the placenta during early pregnancy
Rh status Hemolytic Disease of the Fetus and Newborn Rh incompatibility occurs when a pregnant woman has Rh-negative blood and the fetus has Rh-positive blood. Rh incompatibility can result in destruction of the fetus’s red blood cells, sometimes... read more is determined because a pregnant woman with Rh-negative blood must be treated with Rho(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 Rh Incompatibility Hemolytic Disease of the Fetus and Newborn Rh incompatibility occurs when a pregnant woman has Rh-negative blood and the fetus has Rh-positive blood. Rh incompatibility can result in destruction of the fetus’s red blood cells, sometimes... read more ).
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 in case blood transfusion is needed). If blood loss is substantial or shock develops, blood tests are done to determine whether blood can clot normally.
Typically, ultrasonography is done using an ultrasound device inserted into the vagina. 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, a miscarriage is diagnosed. If a heartbeat is detected, miscarriage is much less likely but may still occur.
Ultrasonography can also help identify the following:
A miscarriage that is incomplete, is infected, or has been missed
Any parts of the placenta or other pregnancy-related tissues that remain in the uterus
A ruptured corpus luteum cyst
A hydatidiform mole or other form of gestational trophoblastic disease
Sometimes 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 a ruptured ectopic pregnancy is low, hCG levels are measured frequently and ultrasonography is repeated as needed. If the likelihood of a ruptured ectopic pregnancy 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 immediately 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 Rho(D) immune globulin to prevent her from producing antibodies that may attack the fetus's red blood cells in subsequent pregnancies.
