Ectopic Pregnancy 

What are the risk factors for developing ectopic pregnancy?

• > 50% of women with ectopic pregnancies will give no history of any risk factors.
• High risk  
  • fallopian tube surgery
  • tubal sterilization
  • previous ectopic pregnancy
  • DES (diethylstilbestrol) exposure in utero
  • IUD
  • documented tubal abnormality
• Moderate risk  
  • technology assisted pregnancies
  • previous genital infections
  • prior abdominal or pelvic surgery

What is the clinical setting when you will consider ectopic pregnancy?

• Symptoms:
  • nonspecific, 50% misdiagnosed at initial visit
  • 40-50% vaginal bleeding, often mistaken for menstrual period  
  • N/V, breast tenderness, fatigue  
  • Abdominal pain radiating to shoulder is associated with ectopic rupture
• Physical findings  
  • 75% abdominal tenderness, +/- rebound tenderness  
  • 66% cervical motion tenderness  
  • 50% palpable adnexal mass  
  • 20% hemodynamic compromise (orthostasis, hypotension, shock)   

In a patient who is in the high-risk group for developing an ectopic pregnancy, screening with quantitative beta-HCG, progesterone, and sonography should be done as soon as pregnancy is confirmed. 

What are the useful modalities in evaluating ectopic pregnancy? What is the utility of each procedure?

• Vaginal sonography: This can be used to detect uterine gestation as early as 1 week after missed menses with a serum beta-hCG is higher than 1500 mIU/mL.  An empty uterus with a serum beta-hCG of 1500 mIU/mL or higher was 100 percent accurate in identifying an ectopic pregnancy.  Ectopic pregnancies can be missed, though, when a tubal mass is small or obscured by bowel.  For identifying an ectopic pregnancy, the sensitivity is 96% and specificity is 99% when free peritoneal fluid is identified.  However, when there is a tubal mass, the sensitivity is 81% and the specificity if 99%. 

•  Vaginal Color and Pulsed Doppler Ultrasound: This consists of identifying a uterine or extra uterine site of vascular color in a “ring of fire” pattern (characteristic placental shape) and a high-velocity low-impedence flow pattern that is compatible with placental perfusion.  If this pattern is seen outside the uterine cavity and also appears “cold” with respect to blood flow, the diagnosis of ectopic pregnancy is apparent. 

• Abdominal sonography:  Identification of pregnancy products in the fallopian tube is difficult using abdominal ultrasonography.  A uterine pregnancy is usually not recognized using abdominal ultrasound until 5 to 6 menstrual weeks or 28 days after timed ovulation.  Demonstration of an adnexal or cul-de-sac mass by sonography is not necessarily helpful (could be corpus luteum cyst or matted bowel).  Identification of fetal heart action outside the uterine cavity is firm evidence of an ectopic pregnancy.

What are the imaging findings of ectopic pregnancy?

An empty uterus and an ectopic pregnancy are seen with visualization of an adnexal mass separate from two clearly identified ovaries  Mass must be complex, or contain a gestational saclike adnexal ring; fetal pole can be present or absent 

Right ectopic. Short arrow points to amorphous material within the yolk sac in the featal pole.
Gestational sac in adnexa
No intrauterine pregnancy. Increased serum HCG.
No intrauterine pregnancy. Free fuid may be from follicualr rupture. Serum HCG is not increased.
Normal