Symptomatic nephrolithiasis complicating pregnancy.

OBJECTIVE To review our experiences with diagnosis and management of symptomatic nephrolithiasis complicating pregnancy and to ascertain the efficacy of renal sonography for initial diagnosis compared with plain x-rays or single-shot intravenous pyelography. METHODS Perinatal outcomes were evaluated for all pregnant women admitted to Parkland Hospital for nephrolithiasis from 1986 to 1999. Diagnostic studies and management of nephrolithiasis were also evaluated. RESULTS During the 13-year study period, 57 pregnant women had 73 admissions for symptomatic nephrolithiasis. Symptomatic nephrolithiasis complicated 1 in 3300 (0.03%) deliveries at our institution. Only 12 women (20%) had a history of renal calculi. Mean gestational age at diagnosis was 23 weeks. Imaging techniques included renal ultrasonography, plain abdominal x-ray, and single-shot intravenous pyelography. Calculi were visualized in 21 of 35 (60%) renal ultrasonographic examinations and 4 of 7 (57%) abdominal x-ray studies when these were performed as the initial test. In contrast, urolithiasis was discovered in 13 of 14 (93%) instances in which intravenous pyelography was performed as the initial diagnostic test. When sonography was negative (n = 14), renal calculi were confirmed by single-shot intravenous pyelography (n = 8). Although 43 of 57 (75%) of symptomatic episodes responded to conservative management, 10 women required ureteral stents, 3 needed percutaneous nephrostomy tubes, and 2 underwent ureteral laser lithotripsy for resolution. CONCLUSION Although the convenience and safety of ultrasonography to initially diagnose nephrolithiasis are indisputable, 40% of calculi were missed when this method alone was used. Thus, if nephrolithiasis is still suspected clinically despite ultrasonographic findings, single-shot pyelography is recommended.