Objective:To investigate the level of vitamin D in patients with intrahepatic cholestasis of pregnancy(ICP),and analyze the relationship between vitamin D level and ICP and pregnancy outcome.Methods:230 ICP patients were selected as case group and 327 normal pregnant women were selected as control group.General data,vitamin D levels,liver function and perinatal outcomes of the two groups were compared,and correlation analysis was performed.The predictive value of vitamin D levels in adverse pregnancy outcomes was analyzed using receiver operating characteristic curve(ROC).Results:There were sta-tistically significant differences in age,birth time,previous ICP history,symptoms,liver function,vitamin D level in late preg-nancy and pregnancy outcome between the two groups(P<0.05).There was no significant difference in the levels of serum vi-tamin D in the first trimester and the second trimester between the two groups(P>0.05).Correlation analysis showed that there was a negative correlation between serum vitamin D and serum total bile acid(TBA)in late pregnancy(r=-0.204,P<0.001).In ICP patients,the serum vitamin D level in the third trimester in the adverse pregnancy outcome group was lower than that in the non-adverse pregnancy outcome group,and the difference between the groups was statistically significant(P<0.05).ROC curve analysis showed that serum vitamin D level in late pregnancy had a certain predictive value for adverse preg-nancy outcomes in ICP patients(P<0.001).Conclusion:The serum vitamin D in the case group was lower than that in the con-trol group,and there was a negative correlation between vitamin D and TBA.The level of vitamin D in the late trimester of pregnant women in the case group has a certain predictive value for adverse pregnancy outcomes,and vitamin D supplementa-tion should be appropriately strengthened during pregnancy to improve maternal and infant outcomes.