First trimester
Light bleeding in the first trimester is common. There are many different reasons you could be spotting.
Implantation bleeding
You may bleed a little when the embryo attaches to the lining of your uterus. This may occur 10-14 days after fertilization. Although this spotting is usually earlier and lighter than a menstrual period, some women don't notice the difference, and don't even realize they're pregnant.
Changes in the cervix
Your cervix changes during pregnancy to prepare for delivery. More blood flows to your cervix while you're pregnant, so the area is sensitive. You may have some light bleeding after sex or after a pelvic exam.
Miscarriage
Miscarriage usually happens during the first 12 weeks of pregnancy. Bleeding doesn't always mean miscarriage. At least half of women who have spotting or light bleeding early in pregnancy don't miscarry. Other signs of miscarriage include cramps (stronger than menstrual cramps) and tissue coming out of the vagina. If you think you may have had a miscarriage, call your health care provider. For more information, read Miscarriage.
Molar pregnancy
This is a rare condition in which tissue grows in the uterus, but the embryo is abnormal or missing. With molar pregnancy, bleeding may be dark brown in color. Other symptoms include severe nausea and vomiting and cramping in the belly. If you have any of these symptoms, call your health care provider right away. For more information, read Molar Pregnancy.
Later in pregnancy
Bleeding later in pregnancy can be caused by many things. Tell your health care provider immediately if you have bleeding in the second half of pregnancy.
Bleeding later in pregnancy may be caused by a number of health conditions.
Cervical problems
An infection, inflammation, or growths on the cervix can cause vaginal bleeding. For a few women, light bleeding is a sign of cervical insufficiency (CI), also known as cervical incompetence, in which the cervix opens without warning. This can result in preterm labor and delivery. Cervical insufficiency or incompetence is most common between 18-23 weeks. It requires immediate medical attention.
Preterm labor
Light bleeding may be a sign of preterm labor. If you have any of the following signs or symptoms, call your health care provider right away:
Miscarriage
Miscarriage usually happens in the first trimester, but it can occur at any time before 20 weeks of pregnancy.
Placenta previa
Heavy bleeding late in pregnancy may be a sign of placenta previa. If you have heavy bleeding, go to the hospital right away. With placenta previa, the placenta is attached too low in the uterus. It partly or completely covers the birth canal. This is a serious condition. The main sign is painless, bright red vaginal bleeding. The bleeding may stop on its own, but then come back a few days or weeks later.
Placental abruption
A few pregnant women have placental abruption, in which the placenta separates from the wall of the uterus before birth. This leads to bleeding within the uterus. The woman often also has pain in her belly. Placental abruption usually occurs in the last 12 weeks of pregnancy. If you have heavy bleeding, go to the hospital right away.
Uterine rupture
For women who've had a previous c-section, a tear in the scar in the uterus may cause bleeding. This opening is very dangerous. The woman will feel intense pain and tenderness in her belly.
A sign of normal labor
"Bloody show" is normal at the very end of pregnancy. If you have thick discharge that is pink or slightly bloody 1-2 weeks before your due date, your body is probably taking the first step to prepare for labor.
Other causes of bleeding may be unrelated to the pregnancy itself.
When to call your health provider
Contact your health care provider if you have:
May 2007