title: Monitoring intrahepatic cholestasis of pregnancy using the fetal myocardial performance index: a cohort study.
abstract: OBJECTIVE
  To investigate use of the fetal myocardial performance index (MPI) in assessing intrahepatic cholestasis of pregnancy (ICP).
  
  
  METHODS
  This was a cohort study including cross-sectional and longitudinal data from 31 women with ICP recruited from June 2012 to March 2014. Fetal left, right and delta MPI (LMPI, RMPI and DMPI), and routine measures of fetal growth and wellbeing, were obtained at each ultrasound examination. Results were evaluated with respect to gestational age (GA)-adjusted reference intervals, level of maternal serum bile acid (SBA) and fetal outcome. Lower SBA (≥ 7.5 and < 40 μmol/L) and high SBA (≥ 40 μmol/L) subgroups of cases were defined for the analysis.
  
  
  RESULTS
  A total of 51 ultrasound examinations were performed in 33 fetuses. The mean LMPI, and means of its isovolumetric relaxation time (IRT) and isovolumetric contraction time (ICT) components were significantly higher in all subgroups of cases of ICP relative to the normal reference mean. Considering only the first examination in each case of ICP, IRT was significantly more prolonged in the high SBA group (n = 10) in comparison to the lower SBA group (n = 23) (52.7 ± 8.0 ms vs 47.3 ± 4.8 ms, P = 0.02), and both IRT (r = 0.538, P = 0.001) and LMPI (r = 0.367, P = 0.036) were significantly correlated with SBA concentration. The proportion of high SBA cases with LMPI, RMPI or DMPI > 2 SD above the GA-adjusted reference mean was not significantly greater than for the lower SBA group. On analysis of all data from those cases with more than one examination, no significant correlation was found between SBA concentration and any of the MPI variables.
  
  
  CONCLUSIONS
  LMPI values increase above the population GA-adjusted mean in cases of ICP, particularly amongst women with higher SBA. A significant correlation between IRT and LMPI at initial examination and increasing SBA concentration was found. A future multicenter prospective study may clarify the prognostic utility of MPI in ICP.
authors.affiliation: School of Women's and Children's Health, UNSW Medicine, Randwick, NSW, Australia.|Department of Maternal-Fetal Medicine, Royal Hospital for Women, Randwick, NSW, Australia.|Women's and Children's Health, St George Hospital, Kogarah, NSW, Australia.|Australian Centre for Perinatal Science, UNSW Medicine, Randwick, NSW, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Henry
authors.affiliation: School of Women's and Children's Health, UNSW Medicine, Randwick, NSW, Australia.|Department of Maternal-Fetal Medicine, Royal Hospital for Women, Randwick, NSW, Australia.|Australian Centre for Perinatal Science, UNSW Medicine, Randwick, NSW, Australia.
authors.forename: A W
authors.initials: AW
authors.lastname: Welsh
mesh_terms: D000328:Adult; D002780:Cholestasis, Intrahepatic / Q000097:blood / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D047109:Fetal Development; D005318:Fetal Heart / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008137:Longitudinal Studies; D009200:Myocardial Contraction; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000503:physiopathology*; D012016:Reference Values; D050497:Stillbirth; D016216:Ultrasonography, Prenatal
keywords: Tei index; functional fetal echocardiography; intrahepatic cholestasis of pregnancy; myocardial performance index