Bleeding During Pregnancy
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Vaginal bleeding during pregnancy has many causes. Some are serious and others are not. Bleeding can occur early or later in pregnancy. Bleeding in early pregnancy is common. In many cases, it does not signal a major problem. Bleeding later in pregnancy can be more serious. Contact your obstetrician–gynecologist (ob-gyn) if you have any bleeding at any time during pregnancy.
Bleeding in the first trimester happens in 15 to 25 in 100 pregnancies. Light bleeding or spotting can occur 1 to 2 weeks after fertilization when the fertilized egg implants in the lining of the uterus. The cervix may bleed more easily during pregnancy because more blood vessels are developing in this area. It is not uncommon to have spotting or light bleeding after sexual intercourse or after a Pap test or pelvic exam.
Problems that can cause bleeding in early pregnancy include infection, early pregnancy loss, and ectopic pregnancy.
Loss of a pregnancy during the first 13 weeks of pregnancy is called early pregnancy loss or miscarriage. It happens in about 10 in 100 known pregnancies. Bleeding and cramping are signs of early pregnancy loss. But about half of women who have a miscarriage do not have any bleeding beforehand.
If you have had an early pregnancy loss, some of the pregnancy tissue may be left in the uterus. This tissue needs to be removed. You can allow the tissue to pass naturally, or it can be removed with medication or surgery. (See Early Pregnancy Loss.)
An ectopic pregnancy occurs when the fertilized egg does not implant in the uterus but instead implants somewhere else, usually in one of the fallopian tubes. If the fallopian tube ruptures, internal bleeding can occur. Blood loss may cause weakness, fainting, pain, shock, or even death.
Sometimes vaginal bleeding is the only sign of an ectopic pregnancy. Other symptoms may include abdominal, pelvic, or shoulder pain. These symptoms can occur before you even know you are pregnant. If you have these symptoms, call your ob-gyn right away. The pregnancy will not survive, and it must be removed with medication or surgery. (See Ectopic Pregnancy.)
Common problems that may cause light bleeding later in pregnancy include inflammation of or growths on the cervix. Heavy bleeding is a more serious sign. Heavy bleeding may be caused by a problem with the placenta. Any amount of bleeding also may signal preterm labor. If you have any bleeding late in pregnancy, contact your ob-gyn right away or go to the hospital.
Several problems with the placenta later in pregnancy can cause bleeding:
Placental abruption—In placental abruption, the placenta detaches from the wall of the uterus before or during birth. The most common signs and symptoms are vaginal bleeding and abdominal or back pain. Placental abruption can cause serious complications if it is not found early. The fetus may not get enough oxygen, and the pregnant woman can lose a large amount of blood.
Placenta previa—When the placenta lies low in the uterus, it may partly or completely cover the cervix. This is called placenta previa. It may cause vaginal bleeding. This type of bleeding often occurs without pain. Some types of placenta previa resolve on their own by 32 to 35 weeks of pregnancy as the lower part of the uterus stretches and thins out. Labor and delivery then can happen normally. If placenta previa does not resolve, you may need to have a cesarean birth.
Placenta accreta—When the placenta (or part of the placenta) invades and is inseparable from the uterine wall, it is called placenta accreta. Placenta accreta can cause bleeding during the third trimester and severe blood loss during delivery. Most cases can be found during pregnancy with a routine ultrasound exam. Sometimes, though, it is not discovered until after the baby is born. If you have placenta accreta, you are at risk of life-threatening blood loss during delivery. Your ob-gyn will plan your delivery carefully and make sure that all needed resources are available. You may need to have your baby at a hospital that specializes in this complication. Hysterectomy often needs to be done right after delivery to prevent life-threatening blood loss.
Late in pregnancy, vaginal bleeding may be a sign of labor. If labor starts before 37 weeks of pregnancy, it is called preterm labor. Other signs of preterm labor include the following:
Change in vaginal discharge (it becomes watery, mucus-like, or bloody) or increase in amount of vaginal discharge
Pelvic or lower abdominal pressure
Constant, low, dull backache
Mild abdominal cramps, with or without diarrhea
Regular or frequent contractions or uterine tightening, often painless (four times every 20 minutes or eight times an hour for more than 1 hour)
Ruptured membranes (your water breaks—either a gush or a trickle)
How preterm labor is managed is based on what is thought to be best for your health and your fetus’s health. In some cases, medications may be given. When preterm labor is too far along to be stopped or there are reasons that the baby should be born early, it may be necessary to deliver the baby. (See Preterm Labor and Birth.)
Cervix: The lower, narrow end of the uterus at the top of the vagina.
Cesarean Birth: Birth of a fetus from the uterus through an incision (cut) made in the woman’s abdomen.
Complications: Diseases or conditions that happen as a result of another disease or condition. An example is pneumonia that occurs as a result of the flu. A complication also can occur as a result of a condition, such as pregnancy. An example of a pregnancy complication is preterm labor.
Ectopic Pregnancy: A pregnancy in a place other than the uterus, usually in one of the fallopian tubes.
Egg: The female reproductive cell made in and released from the ovaries. Also called the ovum.
Fallopian Tubes: Tubes through which an egg travels from the ovary to the uterus.
Fertilization: A multistep process that joins the egg and the sperm.
Hysterectomy: Surgery to remove the uterus.
Inflammation: Pain, swelling, redness, and irritation of tissues in the body.
Miscarriage: Loss of a pregnancy that is in the uterus.
Obstetrician–Gynecologist (Ob-Gyn): A doctor with special training and education in women’s health.
Oxygen: An element that we breathe in to sustain life.
Pap Test: A test in which cells are taken from the cervix (or vagina) to look for signs of cancer.
Pelvic Exam: A physical examination of a woman’s pelvic organs.
Placenta: An organ that provides nutrients to and takes waste away from the fetus.
Placenta Accreta: A condition in which part or all of the placenta attaches abnormally to the uterus.
Placental Abruption: A condition in which the placenta has begun to separate from the uterus before the fetus is born.
Placenta Previa: A condition in which the placenta covers the opening of the uterus.
Preterm: Less than 37 weeks of pregnancy.
Sexual Intercourse: The act of the penis of the male entering the vagina of the female. Also called “having sex” or “making love.”
Trimester: A 3-month time in pregnancy. It can be first, second, or third.
Ultrasound Exam: A test in which sound waves are used to examine inner parts of the body. During pregnancy, ultrasound can be used to check the fetus.
Uterus: A muscular organ in the female pelvis. During pregnancy, this organ holds and nourishes the fetus. Also called the womb.
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Last updated: May 2021
Last reviewed: November 2020
Copyright 2021 by the American College of Obstetricians and Gynecologists. All rights reserved. Read copyright and permissions information.
This information is designed as an educational aid for the public. It offers current information and opinions related to women's health. It is not intended as a statement of the standard of care. It does not explain all of the proper treatments or methods of care. It is not a substitute for the advice of a physician. Read ACOG’s complete disclaimer.
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