Pregnancy and abdominal pain: Value of ultrasound in diagnosis

Ultrasound is noninvasive, safe, and versatile. It seems an ideal imaging modality in the pregnant patient, in whom ionizing radiation must be kept to a minimum, yet accurate imaging is important in directing treatment. The objective of our study was to investigate the value of ultrasound as a first-line imaging modality in pregnant women with abdominal pain. We prospectively studied 41 consecutive pregnant patients with abdominal pain over a 1-year period. The setting was a busy private practice in a large teaching hospital with both a primary and tertiary care referral base. Diagnoses were categorized into urologic, biliary, bowel, and obstetric/gynecologic pathology. There were 23 positive diagnoses of the 41 patients in the series, encompassing 13 cases of urinary pathology (calculi, pyelonephritis, and overdistention syndrome), 2 cases of bowel pathology (appendicitis and Crohn's disease), 6 cases of biliary disease (gallstones and a case of choledocholithiasis), and 2 cases of obstetric/gynecologic pathology (threatened abortion and corpus luteum cyst). Ultrasound correctly diagnosed 18 of these 23 cases. The remaining 5 false-negatives were 3 cases of urinary calculi, 1 case of appendicitis, and 1 case of choledocholithiasis. There were 18 true-negative and no false-positives. The sensitivity of ultrasound in our series was 78%, specificity was 100%, and overall accuracy was 88%. Although there are limited numbers of specific diagnoses, we think that our patient population as a whole represents some of the more commonly evaluated complications in pregnancy. We conclude that sonography is a valuable first-line imaging modality in diagnosis of the pregnant patient with pain.