Abstract: Background：Intrahepatic cholestasis of pregnancy (ICP) may lead to adverse neonatal outcomes. Objective：To investigate the risk factors of Neonatal Intensive Care Unit (NICU) admission of newborns delivered by mothers with ICP within 24 hours after birth. Design：Singlecenter casecontrol study. Methods：From January 2015 to December 2019, the newborns whose mothers gave birth to a single baby at Maternal and Child Health Hospital of Chongiqng Yongchuan District and were diagnosed with ICP were selected as the study subjects. According to whether they were admitted to NICU within 24 hours of life, they were divided into NICU admission group and nonNICU admission group. Sample size was estimated that 131 newborns would be needed at least in each group. The clinical data of mothers and newborns were retrospectively analyzed, and the risk factors of NICU admission within 24 hours of life were analyzed by binary logistic regression model. Receiver operating characteristic (ROC) curve was used to predict the the independent risk for the NICU admission factors. Main outcome measures：The risk factors and predictive factors of NICU admission of newborns delivered by mothers with ICP within 24 hours of life. Results：A total of 621 newborns (308 males) delivered by mothers with ICP were included. The average gestational age was 38.3 (37.0, 39.3) weeks, and the average birth weight was 3 148±461 g. There were 133 (21.4%) newborns admitted to NICU within 24 hours of life because of preterm(n=78), respiratory distress(n=20), hypoglycemia, poor response, infection and 488 newborns were not admitted to NICU. Compared with the nonNICU admission group, the gestational age, birth weight, 5 min Apgar score and gestational age at diagnosis of the NICU admission group were lower, and the ALT, AST, bile acid of last test, and preterm of the NICU admission group were higher, and the differences were statistically significant. One (0.16%) newborn died at followup within 28 days of life. Logistic regression analysis showed that small gestational age (OR=0.378, 95%CI: 0.3010.474, P<0.001), itch (OR=2.410, 95%CI: 1.4114.114, P=0.001), high bile acid (OR=1.016, 95%CI: 1.0031.028, P=0.012) and low BMI before pregnancy (OR=0.930, 95%CI: 0.8730.990, P=0.023) were the risk factors of NICU admission. The predictive factors of NICU admission of newborns delivered by mothers with ICP within 24 hours of life were as the follow: a. When those mothers were combined with itch, the sensitivity was 96.7% (95%CI: 90.8%99.3%) for the combination of gestational age (the optimal cutoff: ≤36.6 weeks), maternal bile acid (the optimal cutoff: >20 umol·L-1) and BMI before pregnancy (the optimal cutoff: ≤24 kg·m-2); b. When those mothers were not with itch, the sensitivity was 78.0% (95%CI: 62.4%82.4%) for the combination of gestational age (the optimal cutoff: ≤36.5 weeks), maternal bile acid (the optimal cutoff: >26.8 umol·L-1) and BMI before pregnancy (the optimal cutoff: ＞24 kg·m-2). Conclusion：Small gestational age, itch, high bile acid level and low BMI before pregnancy of the mother were independent risk factors for NICU admission of newborns delivered by mothers with ICP. When those mothers were with itch, the sensitivity was 96.7% for the prediction of NICU admission through the combination of gestational age ≤36.6 weeks, maternal bile acid >20 umol·L-1 and BMI before pregnancy ≤24 kg·m-2.

Key words: Intrahepatic cholestasis of pregnancy, Neonatal intensive care unit, Risk factors, Sensitivity, Specificity