Statistical Analysis
R statistical software was used to perform the statistical analyses. Due to non-normal distribution of the data an unpaired Wilcoxon test was applied to compare the clinical characteristics of the two study groups. Analysis of this study involved measurement of sHLA-G i.e., a dependent variable over time (independent variable) during the course of pregnancy in the pregnant mothers. It represents a classical design of repeatedly measured longitudinal data. Linear mixed effect model was used to analyze this longitudinal data in order to determine changes in the sHLA-G levels during pregnancy in the mothers delivering SGA and those delivering AGA. This method of analyzing the data was selected as it allowed for the inclusion of multiple measurements (of sHLA-G) per participant (i.e., one measurement at each time point they were assessed), and also allowed the inclusion of pregnant women who did not have all the measurements in the analysis, whether due to nonavailability of the sera sample at postpartum (42 days to 6 months) or because sHLA-G levels were undetectable in some mothers at certain time-points (26 to 28 weeks and delivery) of pregnancy. This model could also account for the subject-specific variability generated in our study as all the mothers were not sampled at exactly the same day of pregnancy.