Utility of ultrasound for evaluating the appendix during the second and third trimester of pregnancy

This study aims to retrospectively evaluate the right lower quadrant ultrasounds in women presenting during the second or third trimester of pregnancy for the frequency of appendix visualization and accuracy in diagnosing appendicitis. Institutional Review Board approval was obtained for this Health Insurance Portability and Accountability Act-compliant study. We reviewed imaging records from 99 consecutive pregnant women from 2001 to 2011 who presented during the second (≥14 weeks gestation) or third trimester for right lower quadrant ultrasound to evaluate the appendix. Visualization of the appendix as well as the size and compressibility, if identified, were recorded. The medical records and labs related to the initial patient presentation, subsequent management, and follow-up were reviewed for surgical and clinical outcomes. Pathology records were reviewed to determine if appendicitis was present when appendectomy was performed. Patients who underwent appendectomy were considered to have appendicitis based on pathology results, and patients managed non-operatively with symptom improvement and those with a normal appendix at pathology were considered to not have appendicitis. During the study period, 99 women meeting inclusion criteria presented to our institution for right lower quadrant ultrasound to evaluate the appendix during the second or third trimester of pregnancy. The mean gestational age at presentation was 23 weeks (±7 weeks). The mean maternal age was 28 years (±6.6 years). The appendix was not visualized in 97% (96/99) of right lower quadrant ultrasound examinations. Of the three studies in which the appendix was visualized, two were considered positive for appendicitis and one was considered negative. Eight patients in this group ultimately underwent appendectomy, including the two patients with positive right lower quadrant ultrasounds, and appendicitis confirmed at pathology in seven of these cases (87.5%). Right lower quadrant ultrasound successfully demonstrated an abnormal appendix in 28.7% (two of seven) of surgically confirmed cases; however, this technique did not detect appendicitis in 71% (five of seven) of patients with surgically proven disease due to nonvisualization of the appendix. Retrospective review of right lower quadrant ultrasounds performed during the second and third trimester of pregnancy suggests that this modality has limited utility for diagnosing appendicitis due to infrequent visualization of the appendix.