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).