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Ultrasound scanning in the diagnosis of acute appendicitis in pregnancy

Three Part Question

In [women with possible appendicitis in pregnancy] is [abdominal ultrasonography] good at [ruling in or ruling out appendicular disease]

Clinical Scenario

A 28 year old woman presents to the emergency department with a 4 hour history of right iliac fossa pain, and an examination suggestive of acute appendicitis. You are aware that an isolated blood count is neither specific nor sensitive in the diagnosis of appendicitis, and the on-call surgeon suggests that an ultrasound scan may be helpful.

Search Strategy

Medline 1950 to February Week 2 2007
Embase 1980 to 2007 Week 08. Using the OVID interface
The Cochrane Library Issue 1 2007
[ or exp Appendicitis/] OR [exp Ultrasonography/ or OR OR] AND [exp Pregnancy/ OR exp Pregnancy Complications/ OR exp Pregnancy, Abdominal/ OR] Limit to English language and Human.
Diagnosis Clinical Query filter (specificity)
Cochrane:Appendicitis[MeSH explode all trees] AND Pregnancy [MeSH explode all trees] 0 results

Search Outcome

10 papers were found, of which 7 were irrelevant or of insufficient quality for inclusion. The 3 remaining papers are shown below

Relevant Paper(s)

Author, date and country Patient group Study type (level of evidence) Outcomes Key results Study Weaknesses
Lim et al,
42 pregnant women with clinically suspected appendicitis. Gold standard operative finding (22) or observation for a median of 3 weeks (23)Diagnostic test studySensitivity of USS100%Small numbers Unclear selection Varying trimesters 3 women in third trimester excluded as uterus too large
Specificity of USS96%
Likelihood ratiosPositive 27.0

Negative 0.060
Barloon et al,
22 pregnant women with clinically suspected acute appendicitis. Gold standard operative finding or clinical follow up for a mean period of 19 months (6 to 36 months)Diagnostic test studySensitivity of USS67%Those not presenting with 'classical acute appendicitis' were not scanned Small numbers Varying trimesters scanned
Specificity of USS95%
Likelihood ratiosPositive 12.6%

Negative 0.35
Mullins et al,
29 women with suspected appendicitis who had ultrasound scans performed over a 12 year period Gold standard operative findings or record reviewRetrospective cohortSensitivity of USS100%22 indeterminate scans not included in analysis thus reported clinical utility is for 7 scans
Specificity of USS83.3%


The results of these studies need to be viewed with caution. All suffer from the handicap of small numbers, likely selection biases and the absence of a gold standard. The analysis of the third study is seriously flawed in that indeterminate scans are not included.

Clinical Bottom Line

A positive USS may be useful in the diagnosis of acute appendicitis during pregnancy. Those patients with a negative scan should be further investigated and observed until the symptoms resolve or an alternative diagnosis is reached.


  1. Lim HK, Bae SH, Seo GS. Diagnosis of acute appendicitis in pregnant women: value of sonography. American Journal of Roetgenology 1992;159(3):539-542.
  2. Barloon TJ, Brown BP, Abu-Yousef MM et al. Sonography of acute appendicitis in pregnancy. Abdominal Imaging 1995;20(2):149-151.
  3. Mullins ME. Rhea JT. Greene MF. Novelline RA. Diagnostic imaging of suspected appendicitis in pregnant women: Comparison of CT to ultrasonography. Emergency Radiology. Vol. 8(5)(pp 262-266), 2001.