Differential Diagnosis for Vaginal Bleeding in Pregnancy

Single Most Likely Diagnosis

• Threatened abortion: This is the most common cause of vaginal bleeding in early pregnancy, often due to implantation of the embryo or hormonal changes. It is characterized by bleeding with or without cramping, but the cervix remains closed.

Other Likely Diagnoses

• Placenta previa: A condition where the placenta partially or completely covers the cervix, leading to bleeding, especially in the second or third trimester.
• Placental abruption: Premature separation of the placenta from the uterus, which can cause bleeding and is associated with abdominal pain and fetal distress.
• Miscarriage: Spontaneous loss of pregnancy before 20 weeks, often accompanied by bleeding and cramping.

Do Not Miss Diagnoses

• Ectopic pregnancy: A pregnancy that develops outside the uterus, often presenting with vaginal bleeding, abdominal pain, and can be life-threatening if not promptly diagnosed and treated.
• Uterine rupture: A rare but potentially catastrophic event, especially in women with a previous uterine scar, which can cause severe bleeding and is life-threatening to both mother and fetus.
• Molar pregnancy: A rare condition where a non-viable fertilized egg implants in the uterus, leading to bleeding and potentially serious complications if not treated.

Rare Diagnoses

• Vaginal or cervical lesions: Polyps, varices, or other vascular anomalies that can cause bleeding.
• Inherited bleeding disorders: Conditions like von Willebrand disease that can increase the risk of bleeding during pregnancy.
• Choriocarcinoma: A rare type of cancer that can occur during pregnancy, often presenting with vaginal bleeding.