妊娠期肝内胆汁淤积症对母儿的影响及其机制

Intrahepatic Cholestasis of Pregnancy:Mechanism and Impacts in Pregnancy and Fetal Outcomes

妊娠期肝内胆汁淤积症(ICP)对母儿均有不良影响。ICP患者妊娠中晚期体内激素水平异常、基因变异、免疫损伤及致痒源释放增多可引起母体皮肤瘙痒、胆汁酸水平升高及肝功能异常、凝血功能障碍及产后出血,孕妇预后佳,主要危及胎儿。类固醇物质代谢障碍、胆汁酸浓度升高可增加子宫肌层对催产素的敏感性、促进宫颈成熟,诱发早产;胆汁酸在组织器官中沉积导致胎盘绒毛血管痉挛、胎盘储备能力下降,通过胎儿心脏及肺脏毒性作用引起胎儿窘迫、死产及新生儿死亡。

Intrahepatic cholestasis of pregnancy is characterized with unexplained pruritus ,elevated concentration of total bile acid and liver transaminases,which are influenced by abnormal hormone level in the second or third trimester,gene mutation,immune injury and increased release of pruritogens. Although it has good prognosis on pregnant women ,it plays an important role on increased risk of adverse fetal outcomes,including preterm delivery,fetal distress,fetal mortality and neonatal respiratory distress syndrome. The abnormal metabolism of steroids and elevated total bile acid increase myometrial sensitivity for oxytocin and promote cervical ripening so as to induce premature delivery. Bile acid desposition in the placenta leads to spasm of placental villous vessels and decreasing placental reserve capacity. Also ,bile acid accumulation can play a toxin role on fetal heart and lung,resulting in cardiac conduction dysfunction and reduced synthesis of pulmonary surfactant. All these contribute to increased rate of fetal distress ,fetal death and neonatal lung injury.