The diagnostic performance of ultrasound for acute appendicitis in pregnant and young nonpregnant women: A case-control study.

BACKGROUND

Ultrasonography is frequently used to diagnose acute appendicitis in women of reproductive age, but its diagnostic value in pregnant patients remains unclear. This study sought to compare the diagnostic performance of ultrasound in pregnant and young nonpregnant women with suspected acute appendicitis.

METHODS

The database of a single tertiary medical center was reviewed for all women of reproductive age who underwent appendectomy either during pregnancy (2000-2014) or in the nonpregnant state (2004-2007) following ultrasound evaluation. The performance of ultrasound in terms of predicting the final pathologic diagnosis was compared between the pregnant and non pregnant groups using receiver operating characteristic curve analysis.

RESULTS

Of 586 young women treated for appendicitis during the study periods (92 pregnant, 494 non-pregnant), 200 underwent preoperative ultrasound [67 pregnant, and 133 nonpregnant young women]. The pregnant and nonpregnant groups were comparable in age and presenting symptoms. There was no significant difference in the predictive performance of ultrasound between the two groups (AUC 0.76 and 0.73 respectively, p = 0.78) or within the pregnant group, by trimester [first (n = 23), AUC 0.73; second (n = 32), AUC 0.67; third (n = 12), AUC 0.86; p = 0.4]. Ultrasound had a positive predictive value of 0.94 in the pregnant group and 0.91 in the nonpregnant group; corresponding negative predictive values were 0.40 and 0.43.

CONCLUSIONS

There appears to be no difference in the ability of ultrasound to predict the diagnosis of acute appendicitis between pregnant women and nonpregnant women of reproductive age. Therefore, similar preoperative imaging algorithms may be used in both patient populations.