Antepartum nephrolithiasis and the risk of preterm delivery.

Antepartum nephrolithiasis presents a complex clinical scenario which often requires an intervention such as ureteral stent or percutaneous nephrostomy tube (PCNT) placement, especially in the setting of urinary tract infection (UTI). We assess the risk of UTI and preterm labor in the setting of antepartum nephrolithiasis. A retrospective review of an administrative dataset for California and Florida was performed, which included pregnant women admitted for a delivery between 2008 and 2011. Antepartum nephrolithiasis admissions were identified, as were urological intervention (ureteral stent/ureteroscopy) or PCNT placement. Descriptive statistics were performed, as was multivariable logistic regression to identify predictors of UTI and preterm delivery. Of the 2,750,776 deliveries included in this dataset, 3904 (0.14%) were complicated by antepartum nephrolithiasis. 71.4% of these patients were managed conservatively, while 20.6% (n = 803) underwent urological intervention and 8.0% (n = 312) underwent PCNT placement. Preterm delivery rates increased from a baseline of 7.0% for patients without a stone to 9.1% for patients with stones managed conservatively, 11.2% for those undergoing a urologic intervention, and 19.6% for patients who had PCNT placement. On multivariable analysis, conservative management (adjusted odds ratio, aOR 1.3), urologic intervention (aOR 1.5), and PCNT (aOR 2.3) placement each independently increased the risk of preterm delivery (all p < 0.001). Antepartum nephrolithiasis is a condition that affects 1 in 714 women and has been correlated with increased risk of UTI and preterm labor. Intervention with ureteral stent or PCNT placement independently increase these risks, however, receipt of a nephrostomy tube confers the greatest risk of UTI and preterm delivery to the antepartum nephrolithiasis patient.