Material-Method
This prospective study included 48 pregnant women with recovered from SARS-CoV-2 infection and 50 control cases. Approval for the study was obtained from Ankara City Hospital Ethics Committee with the decision number E2-21-639. Written consent was obtained from patients. SARS-CoV-2 infection was diagnosed by polymerase chain reaction (PCR) test in patients. Twin pregnancy, maternal systemic disease, fetal anomaly, and aneuploidy were excluded from the study. Fetal echocardiographic evaluations were performed between 24-37 weeks of gestation by the same maternal-fetal medicine specialist using C1-5-RS convex probe (1.75–4.95 Mhz) GE Voluson S10 Ultrasound. The study group and control group were matched for maternal and gestational age. A two-dimensional assessment of the great vessels and Doppler flow interrogation was obtained according to the guidelines of the International Society of Ultrasound in Obstetrics and Gynecology [14]. Aortic (AV) (figure 1) and pulmonary artery valve (PV) (figure 2) diameters were measured in systole [14]. Power Doppler cursor was located in parallel to the long axis of the aorta or pulmonary artery immediately distal to the valves. The angle between the ultrasound cursor and the direction of blood flow was < 10°. The pulmonary and aortic valves flow velocity waveforms were obtained from the left and right ventricular outflow tract views (Figure 3) [15]. Velocity time integral (VTI) and heart rate (HR) were measured and averaged over the three best cardiac cycles. Cardiac outputs for the left and right ventricle (LCO and RCO) were calculated separately as VTI × π (AV or PV diameter/2)2 × HR [15]. Gestational age was determined using first-trimester head-rump length. LCO and RCO z scores were calculated according to the gestational week. Estimated fetal weight (EFW) was calculated with the method of Hadlock et al. Combined cardiac output (CCO = RCO + LCO) was calculated, z score was obtained according to the gestational week [16,17]. Also, CCO was normalized by estimated fetal weight [18]. Demographic and echocardiographic data were compared between recovery from the SARS-CoV-2 infection (RSI) and control groups. Patients in the study group were divided into subgroups according to the World Health Organization (WHO)’s disease severity classification [19]. Echocardiographic and perinatal outcomes were compared between these subgroups.
Descriptive statistics including the mean, standard deviation or median, and minimum-maximum values for numerical measures were calculated for all patients. The normality of the variables was tested with both Shapiro – Wilk and Kolmogorov – Smirnov tests. Two groups were compared with The Student’s t-test and Mann-Whitney U test. One Way ANOVA analysis (and post hoc test to compare groups in case of significant difference) and Kruskal Wallis test, Mann- Whitney U-test with Bonferroni correction were used to compare the groups. For categorical variables, a comparison of variables was performed by Pearson Chi-square test and Fisher’s exact test. The alpha significance level of 0.05 was used to assess statistical significance. Statistical analysis was done with IBM SPSS Statistics 17.0 (IBM Corporation, Armonk, NY, USA).