# Labor and Delivery Complications in Women With Renal Calculi: Increased Risk and Prolonged Hospital Stay

## TL;DR

Pregnant women with kidney stones face higher risks of labor complications and longer hospital stays compared to those without kidney stones.

## Contribution

This study is the first to analyze national data on labor and delivery complications linked to renal calculi during pregnancy in the U.S.

## Key findings

- Pregnant women with kidney stones had an 84.7% rate of labor and delivery complications compared to 28.8% without stones.
- Women with kidney stones had significantly longer hospital stays (5.12 days) than those without (2.56 days).
- Medicare and Medicaid-insured patients had higher odds of complications compared to other insurance types.

## Abstract

Background: Renal calculi, or kidney stones, are a common, non-obstetric cause of hospitalization during pregnancy, yet their impact on labor and delivery outcomes at a national level within the United States remains unclear. This study aims to explore the connection between labor and delivery complications and prolonged hospitalizations in pregnant women diagnosed with kidney stones.

Methods: We conducted a national cross-sectional analysis study by analyzing data from the 2022 Healthcare Cost and Utilization Project National Inpatient Sample (HCUP-NIS). Pregnant patients were identified using delivery-related diagnostic-related group codes. Renal calculi were defined using International Classification of Diseases-10 (ICD-10) code N20.0 and trimester-specific codes O26.831-O26.833. Variables included primary expected payer, race, patient location, socioeconomic status, gestational age, emergency department (ED) service indicator, transfer out indicator, and age at admission. Weighted multivariable logistic regression was used to evaluate associations between renal calculi and labor delivery complications (LDCs).

Results: The analysis included 698,366 cases, representing 3,491,830 cases after data were weighed. Among pregnant patients with renal calculi, 84.7% experienced labor and delivery complications compared to 28.8% of those without renal calculi (p < 0.001). Additionally, pregnant women with renal calculi had significantly longer hospital stays (5.12 ± 7.5 days vs. 2.56 ± 2.2 days, p < 0.001). Insurance status was significantly associated with both renal calculi and LDCs. Patients insured by Medicare (adjusted odds ratio (aOR) 1.58) and Medicaid (aOR 1.14) had higher odds of complications compared to other insurance types. Increased urbanicity and lower median household income quartiles were also associated with increased odds of LDCs.

Discussion: Renal calculi during pregnancy are associated with elevated risks of maternal complications, including increased morbidity, preterm delivery, and prolonged hospitalization. Enhanced surveillance and tailored interventions for high-risk or otherwise vulnerable groups may reduce these adverse outcomes.