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Bleeding in the First Trimester of Pregnancy

Pregnancy is such an exciting time for most of us. But sometimes bleeding can complicate a pregnancy, particularly in the first trimester, or first 12 weeks of pregnancy. Bleeding in the first trimester is usually no cause for alarm and occurs in about 20% of women. But it is important to know the possible causes and get checked out to make sure you and your baby are healthy.

Implantation bleeding. You may experience some normal spotting within the first six to 12 days after you conceive as the fertilized egg implants itself in the lining of the uterus. Some women don’t realize they are pregnant because they mistake this bleeding for a light period. Usually the bleeding is very light and lasts from a few hours to a few days.

Miscarriage. Because miscarriage is most common during the first 12 weeks of pregnancy, it tends to be one of the biggest concerns with first trimester bleeding. About 15% of recognized pregnancies will end in a miscarriage and more than 80% of miscarriages occur within the first three months of pregnancy.. About half of women who bleed in pregnancy eventually miscarry, but that doesn’t necessarily mean that if you’re bleeding you’ve lost the baby, especially if you don’t have any other symptoms.
Other symptoms of miscarriage are strong cramps in the lower abdomen and tissue passing through the vagina.

Ectopic pregnancy. In an ectopic pregnancy, the fertilized embryo implants outside of the uterus, usually in the fallopian tube. If the embryo keeps growing, it can cause the fallopian tube to burst, which can be life-threatening to the mother. Although ectopic pregnancy is potentially dangerous, it only occurs in about 2% of pregnancies.
Other symptoms of ectopic pregnancy are strong cramps or pain in the lower abdomen, and lightheadedness.

Molar pregnancy (also called gestational trophoblastic disease). This is a very rare condition in which abnormal tissue grows inside the uterus instead of a baby. In rare cases, the tissue is cancerous and can spread to other parts of the body. Other symptoms of molar pregnancy are severe nausea and vomiting, and rapid enlargement of the uterus.

Subchorionic hemorrage. This is a fancy way of saying there is bleeding inside the uterus next to the pregnancy. This is diagnosed by ultrasound and does not mean you will miscarry. The blood from this area will start out bright red but become brown as time goes on, and eventually stop.
Additional causes of bleeding in early pregnancy include:

Cervical changes. During pregnancy, extra blood flows to the cervix. Intercourse or a Pap test, which cause contact with the cervix, can trigger bleeding. This type of bleeding isn’t cause for concern.

Infection. Any infection of the cervix, vagina, or a sexually transmitted infection (such as chlamydia, gonorrhea, or herpes) can cause bleeding in the first trimester.

Adapted from Web MD Medical Reference