Early pregnancy bleeding (also called first trimester bleeding) refers to vaginal bleeding before 14 weeks of gestational age. If the bleeding is significant, hemorrhagic shock may occur. Concern for shock is increased in those who have loss of consciousness, chest pain, shortness of breath, or shoulder pain.Common causes of early pregnancy bleeding include ectopic pregnancy, threatened miscarriage, and pregnancy loss. Most miscarriages occur before 12 weeks gestation age. Other causes include implantation bleeding, gestational trophoblastic disease, polyps, and cervical cancer. Tests to determine the underlying cause usually include a speculum examination, ultrasound, and hCG.Treatment depends on the underlying cause. If tissue is seen at the cervical opening it should be removed. For those in whom the pregnancy is intrauterine and who have fetal heart sounds, watchful waiting is generally appropriate. Anti-D immune globulin is usually recommended in those who are Rh-negative. Occasionally, surgery is required.About 30% of pregnant people have bleeding in the first trimester (0 to 14 weeks gestational age). Bleeding in the second trimester (12 to 24 weeks gestational age) is less common. About 15% of those who realize they are pregnant have a miscarriage. Ectopic pregnancy occurs in under 2% of pregnancies. Differential diagnosis
The differential diagnosis depends on whether the bleeding occurs in the first trimester or in the second or third trimesters. Obstetric causes of first trimester bleeding include the following:

Early pregnancy loss is a term often used interchangeably with spontaneous abortion and miscarriage and refers to pregnancy loss during the first trimester.
It is the most common cause of early pregnancy bleeding and is associated only with heavy (versus light) bleeding. However, patients typically remain hemodynamically stable. Threatened early pregnancy loss, often considered a type of early pregnancy loss, refers vaginal bleeding in the presence of an intrauterine pregnancy and a closed cervix. The presence of fetal heart rate largely determines whether the pregnancy will progress to a viable outcome. Ectopic pregnancy refers to a pregnancy outside the uterus, commonly in the fallopian tube. It is a less common but more serious cause of early pregnancy bleeding. Ectopic pregnancies can rupture, leading to internal bleeding that can be fatal if untreated. Implantation bleeding involves a small amount of bleeding that may occur 10 to 14 days after implantation of the fertilized egg. However, there is little evidence to support the existence of such bleeding. Chorionic hematoma is the pooling of blood (hematoma) between the chorion, a membrane surrounding the embryo, and the uterine wall. It occurs in about 3.1% of all pregnancies and is the most common cause of first trimester bleeding. Gestational trophoblastic neoplasia, which refers to pregnancy-related tumors that be either cancerous or non-cancerous. This cause is extremely rare with non-cancerous gestational trophoblastic neoplasia found in 23 to 1,299 cases per 100,000 pregnancies and cancerous forms with a 10-fold lower incidence.Obstetric causes of second/third trimester bleeding include the following:

Bloody show refers to the passage of a small amount of blood or blood-tinged mucus resulting from labor or cervical weakness.