# Pruritus in intrahepatic cholestasis of pregnancy: the role of substance p

## TL;DR

This study found that substance P levels are higher in pregnant women with intrahepatic cholestasis and correlate with the severity of itching.

## Contribution

The study identifies a novel association between elevated substance P and pruritus in intrahepatic cholestasis of pregnancy.

## Key findings

- Serum substance P concentrations were significantly higher in intrahepatic cholestasis of pregnancy patients compared to controls.
- Substance P levels correlated with both the Pruritus Severity Scale and visual analog scale scores for itching.
- Intrahepatic cholestasis of pregnancy was the only factor significantly associated with increased substance P levels.

## Abstract

The aim of this study was to evaluate the role of substance P in pruritus in patients with intrahepatic cholestasis of pregnancy.

This prospective case–control study was conducted on 50 intrahepatic cholestasis of pregnancy patients and 30 gestational age-matched healthy pregnant women. The groups were compared in terms of serum substance P concentrations, and the correlation between these concentrations and self-reported itching was evaluated in patients with intrahepatic cholestasis of pregnancy.

Serum substance P concentrations were higher in patients with intrahepatic cholestasis of pregnancy than in the control group (960 vs. 611 ng/L; p=0.001). In intrahepatic cholestasis of pregnancy patients, there was a statistically significant positive correlation between the serum substance P concentration and both the Pruritus Severity Scale score (r=605, p<0.001) and the visual analog scale score for pruritus (r=483, p<0.001). On multivariable linear regression analysis, only the presence of intrahepatic cholestasis of pregnancy (pruritus) was statistically significantly associated with an increase in the serum substance P concentration (95%CI 145.06–558.16 ng/L; p=0.001).

The concentration of substance P is increased in patients with intrahepatic cholestasis of pregnancy and is correlated with the severity of the pruritus. While the precise role of elevated substance P levels in the etiology of intrahepatic cholestasis of pregnancy remains uncertain, it may contribute to the pathogenesis of pruritus through central and peripheral effects.