Differential Diagnosis for Ectopic Pregnancy vs Spontaneous Abortion

When differentiating between an ectopic pregnancy and a spontaneous abortion, it's crucial to consider various diagnoses to ensure accurate and timely management. The following categories help organize the thought process:

• Single Most Likely Diagnosis
  • Ectopic pregnancy: This is a critical diagnosis to consider early due to its high morbidity and mortality if not promptly treated. Symptoms such as abdominal pain, vaginal bleeding, and a missed period, coupled with a positive pregnancy test, can suggest an ectopic pregnancy, especially if there's an adnexal mass or free fluid in the pelvis on ultrasound.
• Other Likely Diagnoses
  • Spontaneous abortion (miscarriage): This is a common occurrence in early pregnancy and can present with vaginal bleeding and abdominal cramps. The presence of tissue passing through the vagina and confirmation of an intrauterine pregnancy on ultrasound can help differentiate it from an ectopic pregnancy.
  • Threatened abortion: This condition presents with vaginal bleeding in early pregnancy without cervical dilation or tissue passage. Ultrasound confirmation of an intrauterine pregnancy with fetal cardiac activity is key to differentiating it from ectopic pregnancy.
• Do Not Miss Diagnoses
  • Ruptured ectopic pregnancy: This is a life-threatening emergency that requires immediate surgical intervention. Symptoms include severe abdominal pain, significant vaginal bleeding, and signs of hypovolemic shock. Missing this diagnosis can be fatal.
  • Molar pregnancy: Although less common, a molar pregnancy can present with vaginal bleeding and a positive pregnancy test. Ultrasound findings of a "snowstorm" appearance in the uterus and significantly elevated beta-hCG levels are diagnostic.
  • Heterotopic pregnancy: This rare condition, where there's both an intrauterine and an ectopic pregnancy, is more common in women undergoing fertility treatments. It's crucial not to miss the ectopic component, as it can rupture and cause severe morbidity.
• Rare Diagnoses
  • Pseudosarcina (false pregnancy or phantom pregnancy): This psychological condition leads a woman to believe she is pregnant along with physical symptoms that mimic pregnancy, but without an actual pregnancy.
  • Abdominal pregnancy: A rare type of ectopic pregnancy where the embryo implants in the abdominal cavity outside the uterus, fallopian tubes, ovaries, or ligaments that support the uterus.

Each of these diagnoses requires careful consideration of clinical presentation, ultrasound findings, and laboratory results to differentiate between ectopic pregnancy and spontaneous abortion accurately.