Pregnancy of unknown location

Dr Thomas M. Anderson and Radswiki et al.

The term pregnancy of unknown location is assigned when neither an intrauterine pregnancy (IUP) or an ectopic pregnancy is identified on transvaginal ultrasound in the context of a positive pregnancy test.

  • pelvic pain, vaginal bleeding
  • positive pregnancy test
  • serial beta-hCG: has an adjunct role in the diagnosis of ectopic pregnancy, and is useful in the follow-up of clinically stable patients 
  • serum progesterone: lack of progesterone has been considered an indication of nonviability 3
    • <5 ng/mL is a good indication of nonviability, however, larger values cannot exclude an ectopic pregnancy 4

Essentially these patients will present with a "normal" pelvic ultrasound, with no signs of an IUP and normal adnexa 5

Since the most likely underlying diagnosis is nonviable intrauterine pregnancy,6 methotrexate and/or surgical intervention are not recommended in a hemodynamically stable patient.6 Thus, for the hemodynamically stable patient, a short interval repeat ultrasound examination and quantitative beta-hCG level are generally appropriate.5,6

A pregnancy of unknown location basically reflects 4 possibilities:

Share article

Article information

rID: 15322
System: Obstetrics
Synonyms or Alternate Spellings:
  • Pregnancy of unknown location (PUL)
  • Pregnancy of uncertain location (PUL)
  • PUL
  • Gestation of unknown location

Support Radiopaedia and see fewer ads

Cases and figures

  • Case 1
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.