The role of ultrasound in decision-making for the management of suspected acute appendicitis during pregnancy.

PURPOSE: To assess the reliability of ultrasound in diagnosing acute appendicitis (AA) during pregnancy and to determine which preoperative factors contribute to the high rate of negative appendectomies, exposing both mother and fetus to avoidable risk.

METHODS

This retrospective case-control study included 633 women who underwent appendectomy between 2005 and 2023: 211 pregnant patients and 422 non-pregnant controls matched 2:1 by age and BMI. Clinical, laboratory, imaging, surgical, and histopathological data were analyzed. Ultrasound findings were categorized as normal appendix, non-visualized appendix, or suspicious for appendicitis. Multivariable logistic regression was used to identify factors associated with histologically confirmed appendicitis.

RESULTS

Negative appendectomy (NA) was significantly more frequent among pregnant women compared with controls (23.7% vs. 6.6%, p = 0.001). Most NAs in pregnancy occurred after non-suspicious imaging findings (35.5% vs. 2.8%, p = 0.001). Ultrasound showed a higher false-positive rate in pregnant patients (12.2% vs. 6.2%, p = 0.001). In multivariable analysis, fever was inversely associated with histologically confirmed appendicitis during pregnancy (OR = 0.367; 95% CI 0.145-0.931; p = 0.035). MRI, when performed (12 patients), correctly identified all cases of appendicitis.

CONCLUSION

The high negative appendectomy rate during pregnancy reflects the limited reliability of ultrasound when findings are non-suspicious. Despite the urgency of suspected appendicitis in pregnancy, surgical decisions should be balanced against diagnostic certainty. When clinical suspicion persists, confirmation with additional modalities such as MRI should be considered when US is negative or inconclusive, to improve accuracy and reduce unnecessary surgery.