INTRODUCTION
Intrahepatic cholestasis of pregnancy (IHCP) is the most common hepatobiliary system disease of pregnancy that generally occurs in the late second and third trimesters, with the variable incidence between 0,4% and 5% 1. It is diagnosed with new-onset pruritus particularly in palms and soles of the feet and elevated maternal serum bile acids and/or liver function enzymes. Even though IHCP is known as a usually benign disease that is resolved in two or three weeks after delivery, it is associated with adverse perinatal and neonatal outcomes 2-4. Due to the severity of the disease, higher incidence of obstetric complications such as preterm delivery, meconium staining of amniotic fluid, respiratory distress, fetal bradyarrhythmia and fetal demise has been observed1,2. The underlying pathophysiological mechanism to explain these complications has been associated with raised bile acids in fetal tissues 5. As in bile acid accumulation in fetal myocardium, chronic exposure to bile acids disrupts fetal pulmonary development and function by blocking surfactant production1,5. Moreover, in literature, it has been explained that the higher bile acid concentration is detected in cord blood and amniotic fluid, the lower level of pulmonary surfactant is produced and respiratory distress syndrome (RDS) may be observed more often in those newborns 6,7.
Respiratory distress syndrome that may complicate newborns even after term deliveries, still remains the major cause of neonatal intensive care unit (NICU) admissions, neonatal morbidity and mortality8. Due to its importance, to predict respiratory complications before delivery, some different invasive techniques have been described such as assessment of lecithin/sphingomyelin ratio of amniotic fluid. However in the last decade, pulmonary artery acceleration time (AT) to ejection time (ET) ratio (PATET) has been studied as a non-invasive method evaluating pulmonary lung maturation8-11. It has been reported that low PATET ratio has been a reliable ultrasonographic parameter that give tips on fetal lung immaturity particularly has been studied on preterm, small-for-gestational age fetuses 8,9.
Based on previous studies, we hypothesized that effect of IHCP on fetal lung maturation might be detected as evaluating the impact of IHCP on fetal pulmonary artery Doppler parameters. The primary aim of this study was to determine whether PATET was altered in the fetuses whose mothers were complicated by IHCP. The secondary aim was to investigate the association between fetal pulmonary artery Doppler parameters with neonatal outcomes in pregnancies complicated by IHCP.