Placental and Doppler ultrasound findings in pregnant women with SARS-CoV-2 infection

BACKGROUND: Several viral infections cause changes in the placenta. Cytomegalovirus, herpes viruses, and HIV cause increased placental thickness; Zika virus induces focal regions of necrosis; parvovirus B19 causes a structural injury. Umbilical flow can be considered a direct measurement of vascular placental function. OBJECTIVE: This study aimed to compare placental ultrasound and umbilical Doppler findings in pregnant women who tested positive or negative for SARS-CoV-2. Our work aimed to confirm the suspicion of placental infection and the consequence in fetal physiopathology. STUDY DESIGN: Fifty-seven pregnant women who tested positive for SARS-CoV-2 at the time of or 1 month before the ultrasound scan were evaluated. Cases included 9 first trimester, 16 second trimester, and 32 third trimester ultrasound scans. For comparison, 110 pregnant women (controls) were evaluated. They included 19 women in their first trimester, 43 in their second trimester, and 48 in the third trimester. Controls were asymptomatic and tested negative for SARS-CoV-2 infection in the last 72 hours before the ultrasound scan. Fetal biometry, placental thickness, placental lakes and Doppler umbilical vein parameters, including venous cross-sectional area (mean transverse diameter and radius of umbilical vein, mean velocity of umbilical vein), and umbilical vein blood flow were evaluated. RESULTS: Placental thickness (in millimeter) was significantly higher in the group of pregnant women with SARS-CoV-2 infection (53.82 [10–115]) than in the control group (33.82 [12–66]; P<.001) in their second and third trimesters. The frequency of >4 placental lakes was significantly higher in the group of pregnant women with SARS-CoV-2 infection (28/57 [50.91%]) than in the control (7/110 [6.36]; P<.001) in all 3 trimesters. The mean velocity of umbilical vein was significantly higher in the group of pregnant women with SARS-CoV-2 infection (12.45 [5.73–21]) than in the control group (10.81 [6.31–18.80]; P=.001) in all 3 trimesters. Umbilical vein blood flow (in milliliter per minute) was significantly higher in the group of pregnant women with SARS-CoV-2 infection (389.9 [6.52–1496.1]) than in the control group (305.05 [3.11–1441]; P=.05) in all 3 trimesters. CONCLUSION: Significant differences in placental and venous Doppler ultrasound were documented. Placental thickness, placental venous lakes, mean velocity of umbilical vein, and umbilical vein flow were significantly higher in the group of pregnant women with SARS-CoV-2 infection in all 3 trimesters.