Nephrolithiasis during pregnancy: Characteristics, complications, and pregnancy outcome

Purpose: To evaluate obstetric complications and birth outcome in pregnant women with nephrolithiasis. Methods: A retrospective population-based study comparing all pregnancies of women with and without nephrolithiasis between 1989 and 2010 was conducted. Clinical characteristics were compared, and the obstetric risk factors and labor complication were analyzed. Multivariable logistic regression models were constructed in order to identify independent risk factors for nephrolithiasis. Results: During the study period, there were 219,656 deliveries, of which 195 women with nephrolithiasis were identified. Nephrolithiasis in pregnant women was significantly associated with recurrent abortions, mild preeclampsia, chronic hypertension, gestational diabetes mellitus, and cesarean deliveries. Nephrolithiasis was also significantly associated with urinary tract infections, pyelonephritis, hydronephrosis, and hydroureter. Nevertheless, no higher rates of premature rupture of membranes, preterm deliveries, or adverse perinatal outcomes (birth weight, Apgar scores or perinatal mortality) were noted in patients with nephrolithisais. Using a multiple logistic regression model, obesity (odds ratio 4.4, 95% confidence interval 2.1-9.0) and hypertensive disorders (odds ratio 2.8, 95% confidence interval 1.9-4.1) were independently associated with nephrolithiasis. Conclusion: Maternal kidney stones are significantly associated with several pregnancy complications, including recurrent abortions, hypertensive disorders, gestational diabetes, and cesarean deliveries. Nevertheless, it is not associated with adverse perinatal outcomes. These findings raise the question regarding the proper management of small asymptomatic kidney stone in a pregnant woman.