The differential diagnosis depends on whether the<unk>  occurs in the first trimester or in the second/third trimesters. Obstetric causes of first trimester<unk>  include the following:<unk>  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<unk>  and is associated only with heavy (versus light)<unk> . However, patients typically remain hemodynamically stable. *Threatened<unk>  pregnancy loss, often considered a type of<unk>  pregnancy loss, refers vaginal<unk>  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<unk> . Ectopic pregnancies can rupture, leading to internal<unk>  that can be fatal if untreated. *Implantation<unk>  involves a small amount of<unk>  that may occur 10 to 14 days after implantation of the fertilized egg. However, there is little evidence to support the existence of such<unk> . *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<unk> . *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<unk>  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. *Pregnancy loss refers to death of the fetus at any time during pregnancy. Pregnancy loss most commonly occurs during the first trimester, when it is referred to as<unk>  pregnancy loss. *Placenta praevia or vasa praevia refers to the placenta or fetal blood vessels, respectively, covering or being located close to the opening of the uterus. More than half of women affected by placenta praevia (51.6)% have<unk>  before delivery. Vasa praevia occurs in about 0.6 per 1000 pregnancies. *Placental abruption involves the separation of the placental lining from the uterus of the mother. It occurs most commonly around 25 weeks of pregnancy. *Uterine rupture is when the muscular wall of the uterus tears during childbirth or, less commonly, during pregnancy. *Nontubal ectopic pregnancy refers to an ectopic pregnancy that occurs in the ovary, cervix, or intra-abdominal cavity. Other causes of<unk>  include the following: *Postcoital<unk> , which is vaginal<unk>  after sexual intercourse that can be normal with pregnancy. * Iatrogenic causes, or<unk>  due to medical treatment or intervention, such as sex steroids, anticoagulants, or intrauterine contraceptive devices. *Vaginal or cervical<unk> , which may arise from many causes including fibroids, polyps, warts, tumors, vaginitis, or trauma. Importantly, these causes may co-occur with other causes of<unk> . *Lower genitourinary tract<unk> , which may result from a urinary tract infection (UTI), strenuous exercise, or bladder cancer.
Early pregnancy bleeding
Postpartum infections
Obstetrical bleeding
Postpartum bleeding
Recurrent miscarriage
Antepartum bleeding
Drugs in pregnancy
Postcoital bleeding