Pregnancy of unknown location

Case contributed by Dr Matt A. Morgan


Patient presents with vaginal bleeding. B-hCG = 977. LMP 4-5 weeks ago.

Patient Data

Age: 20Y
Gender: Female
  • 9 x 7 x 1 mm intrauterine fluid collection in the lower portion of the uterine cavity
    • anechoic, oblong, and with angular margins
    • located in the lower uterine cavity
    • slightly eccentrically located
    • no evidence of a double decidual layer
  • no definite intrauterine pregnancy (IUP) is identified
  • thickened endometrium
  • prominent right ovarian cystic lesion is compatible with a corpus luteum
  • no free fluid in the cul-de-sac

Case Discussion

This case is meant to review the possible follow up scenarios of a pregnancy of unknown location (PUL).

In this situation, the patient has a positive B-hCG (977), so one can assume that gestational tissue is located somewhere... but where?

There are three main options at the moment:

  • A gestational sac is located somewhere in the uterus, we just can't see it yet, and the fluid is just some intrauterine fluid or blood products (a pseudogestational sac)
  • That fluid used to be the gestational sac, but it is miscarrying
  • An ectopic pregnancy is located somewhere in the pelvis, we just can't see it yet
  • That "pseudogestational sac" is actually the developing gestational sac

In this setting, one could make an argument for any of these possibilities... the only sure thing is that we don't see a normal IUP right now.

Given this, if the patient is asymptomatic with a PUL, she should get a close interval follow up B-hCG and ultrasound (~7 days) to see how the pregnancy is progressing. Two data points over this time frame should give you an idea of what is going on.

If the patient is symptomatic, then referral to OB/GYN is appropriate for management.

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Case information

rID: 34217
Published: 10th Feb 2015
Last edited: 14th Aug 2019
System: Obstetrics
Inclusion in quiz mode: Included

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