Differential Diagnosis for Vaginal Spotting in a Pregnant Patient

• Single most likely diagnosis
  • Placenta previa: This condition, where the placenta partially or completely covers the cervix, is a common cause of vaginal bleeding in the second and third trimesters of pregnancy. The spotting can be triggered by sexual intercourse, digital vaginal examination, or other factors that cause mild cervical trauma.
• Other Likely diagnoses
  • Cervical polyps or cervical lesions: These can cause spotting due to the increased blood flow and sensitivity of the cervix during pregnancy.
  • Vaginal infections: Infections such as bacterial vaginosis or yeast infections can cause spotting, especially if they lead to cervical inflammation.
  • Sexual intercourse: Mild trauma from sexual activity can cause spotting in pregnant women.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Placental abruption: This is a serious condition where the placenta separates from the uterus, which can cause vaginal bleeding and deprive the baby of oxygen and nutrients. It is crucial to diagnose and manage promptly to prevent severe complications.
  • Uterine rupture: Although rare, uterine rupture can occur, especially in women with a history of uterine surgery, and can present with vaginal bleeding among other symptoms.
  • Ectopic pregnancy (in early pregnancy): While less likely in term pregnancies, an ectopic pregnancy that has not been previously diagnosed can present with vaginal bleeding.
• Rare diagnoses
  • Vasa previa: A condition where fetal blood vessels are present in the membranes covering the cervix, which can cause significant bleeding if ruptured.
  • Uterine dehiscence: A partial separation of a previous uterine scar, which can lead to bleeding and other complications.
  • Choriocarcinoma: A rare type of cancer that can cause vaginal bleeding during pregnancy, though it is exceedingly uncommon.