Statistical analysis
Normality of the distribution of continuous variables was assessed by the Kolmogorov-Smirnov test.  Numerical data were expressed as mean and standard deviation (SD) or median and interquartile range (IQR) for normally and non-normally distributed data, respectively.
The distribution of sFLT-1, PLGF, sFLT-1/PLGF ratio, IL-6, TNF-α, endothelin and VCAM were logarithmically transformed to approximate Gaussian distribution. All with the exception of log TNF-α were converted into multiples of the expected median (MoM) after adjustment for maternal characteristics. Log TNF-α was not converted to MoMs as there were no significant independent maternal contributions identified in the multiple regression model. Between group comparisons were made by the ANOVA or the Kruskal-Wallis test, with Bonferroni correction for post-hoc analysis, for normally and non-normally distributed data, respectively. The Chi-square test was used to compare categorical variables.
Statistical analysis was performed using SPSS (Version 24; SPSS Inc, Chicago,IL).