You may have vaginal bleeding during pregnancy for many reasons. In some cases, you may be told it's not something to worry about. But bleeding can be a symptom of something serious, especially if it occurs later in your pregnancy. Here is a look at common causes of vaginal bleeding during pregnancy. Always call your doctor if you have bleeding at any stage of pregnancy.
Bleeding in early pregnancy
Common problems
Common causes of vaginal bleeding during early pregnancy include:
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An infection. An infection in your pelvis or urinary tract can cause bleeding and some abnormal discharge.
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Cervical changes. Pregnancy hormones can make the cervix softer and more likely to bleed. A noncancer growth (polyp) may also form and may cause bleeding.
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Having sex. You may have some bleeding after sex. See your doctor before having sex again.
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Implantation bleeding. Implantation is the fertilized egg attaching to the uterine lining, about 6 to 12 days after conception. You may have some light spotting or bleeding just before you would expect your next period. This is often mistaken for a light period. But the bleeding is often a lighter color and not heavy.
Serious problems
These are some serious problems that can cause vaginal bleeding in early pregnancy.
Early pregnancy loss (miscarriage)
This is a pregnancy loss that occurs before 20 weeks of pregnancy. Symptoms can include bleeding and cramping. Some pregnancy tissue may still be in your uterus. It may pass naturally from your vagina, or you may need to have it removed with medicine or surgery.
Ectopic pregnancy
This happens when the fertilized egg implants outside of the uterus. In most cases, it implants in one of the fallopian tubes. This is very serious and must be treated. If the fallopian tube bursts (ruptures), there may be internal bleeding. This may lead to fainting, shock, or even death. Symptoms of ectopic pregnancy include:
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Vaginal bleeding (sometimes this is the only symptom).
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Belly, pelvic, or shoulder pain.
Molar pregnancy
In rare cases, early bleeding is caused by a molar pregnancy. This occurs when you have an abnormal tissue growth, not an embryo. Symptoms include:
Subchorionic bleeding
This is caused by a blood clot (subchorionic hematoma) that forms when blood collects between the uterine lining and the placenta. In most cases, this goes away on its own with no problems. But in some cases, it may cause the placenta to separate from the uterine wall. And it may be linked to a higher risk of preterm labor and miscarriage. There is no treatment for these blood clots. But your doctor may want you to have regular follow-up exams. You may also be advised not to do any strenuous activity or heavy lifting.
Bleeding later in pregnancy
Vaginal bleeding in the second and third trimesters is often a sign of a more serious problem. If you have any bleeding later in your pregnancy, call your doctor right away.
Common problems that can cause light bleeding later in pregnancy are cervical growths, inflammation, sex, and infection.
Heavy bleeding later in pregnancy is serious. It may mean there is a problem with the placenta.
Placental abruption
This occurs when the placenta separates from the uterine wall too soon Placental abruption is a medical emergency. Sometimes there may be heavy bleeding, but it can also happen with only sudden, constant belly pain or a firm, rigid abdomen. If you have severe pain, pass a large clot, or soak a pad in an hour or less, call 911 or go to the nearest emergency department right away to protect both you and your baby.
Placenta previa
This condition is most common in the third trimester. It occurs when the placenta is attached to the lower part of the uterus, instead of the upper part. This can partly or fully block the cervix. Bleeding may happen suddenly without any pain, but you may have cramping. In some cases, the placenta moves to the top of the uterus as pregnancy advances. But if that doesn’t happen, you will need to have an early C-section.
Placenta accreta
In this condition, part or all of the placenta is too deeply attached to the uterine wall. It can cause vaginal bleeding in the third trimester and life-threatening blood loss during delivery. In some cases, placenta accreta is found during a routine ultrasound. But it may not be found until delivery. If this condition is found before you deliver, you will likely have an early C-section. In many cases, the uterus is also removed (hysterectomy) right after delivery. This is done to prevent severe blood loss.
Preterm labor
Vaginal bleeding that occurs later in pregnancy may also mean you are going into labor.
Bleeding that occurs before 37 weeks may be a sign of preterm labor. You may be given medicine to delay contractions. But if labor can’t be stopped, or there are other specific concerns, you may have to deliver your baby. Symptoms of preterm labor also include:
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Vaginal discharge (may be bloody, watery, or mucus-like).
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Feeling of pressure in the pelvis or lower belly.
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Low back pain.
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Cramps (may occur with diarrhea).
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Contractions.
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Your water breaks (ruptured membranes).