USA: Ultrasound has limited value in pregnant women with acute abdominal pain and a positive physical examination (PE) and in such cases going straight to MRI may be warranted, says a recent study published in SAGE journal The American Surgeon.
Abdominal pain is quite common among pregnant women; however, surgical pathology such as acute appendicitis as a cause of such pain is not. Ultrasound (US) and magnetic resonance imaging (MRI) are diagnostic tests used in addition to history and physical examination. Alexa Marquez, Department of Gynecology and Obstetrics, Ascension Genesys Hospital, Grand Blanc Township, MI, USA, and colleagues elected to find the role of these tests in pregnant patients who presented to our emergency department with acute abdominal pain.

For this purpose, the researchers conducted a retrospective analysis of 136 pregnant women with acute abdominal pain who presented to the emergency department (ED). PE, US, MRI, comorbid conditions, gestational age, and length of stay were reviewed. Institutional review board approval was obtained. The mean age was 26 and the mean gestational age was 24 weeks. Of those patients, there were 81 patients who had a US and MRI performed.
Based on the study, the researchers reported the following:
The US was positive in 16 patients, while the MRI was positive in 25 patients. Three patients went for appendectomy.
The US sensitivity was 0% and specificity 79%. The positive predictive value for the US was 0% and the negative predictive value was 95%, which was less than 100%.
The MRI likelihood ratios were calculated for each test's clinical application and demonstrated that the US test result was indeterminate for ruling in and ruling out appendicitis while the MRI allowed for a high ability to rule out the disease.

The authors concluded, "Acute abdominal pain in pregnant women and a positive PE highly suggestive of surgical pathology, US had limited value and patients should proceed to MRI."
Reference:
Marquez A, Wasfie T, Korbitz H, Wong V, Pearson E, Holsinger H, Hella J, Barber K. Role of Abdominal Ultrasound and Magnetic Resonance Imaging in Pregnant Women Presenting With Acute Abdominal Pain. Am Surg. 2022 Apr 14:31348221087914. doi: 10.1177/00031348221087914. Epub ahead of print. PMID: 35422127.