Statistical analysis
Before the study, power analysis was performed using the G*power program 3.1.9.4 version. Power analysis revealed that 17 patients should be included in both groups at the 0.363 effect size with α:0.05, and 80% power [14]. The data of the study were analyzed by SPSS 25.0 (IBM, USA). The findings of the study are expressed as frequency and percentages. Normality analysis was carried out using the Kolmogorov-Smirnov test. The variables without normal distribution are presented as the median and interquartile range (IQR) with 25-75th percentiles. Categorical variables were compared with the Chi-square test. Numerical variables with and without normal distribution were compared using the independent samples t-test and Mann-Whitney U. Postnatal echocardiography findings of the first and control measurements were compared with the paired samples t-test. Spearman correlation analysis was used to determine possible correlations.p <0.05 was accepted for statistical significance value.