Vertical transmission and kidney damage in newborns whose mothers had coronavirus disease 2019 during pregnancy.

Objectives: Coronavirus disease 2019 (COVID-19) has become a worldwide pandemic. However, the hazard to newborns in pregnancy remains controversial. The aim of this study was to investigate the vertical transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from mother to child and developmental toxicity in the fetus.

Methods: All clinical information was recorded on 22 neonates born to mothers with confirmed COVID-19 pneumonia in Tongji Hospital.

Results: The average birth weight of the 22 newborns (16 males and 6 females) was 2980 g, and the mean gestational week was 37W+3. The birth weight of three babies was <2500 g, and the gestational week of all three low-birth-weight neonates was less than 36W. Three newborns had minor lesions of infection in the lungs as shown by computed tomography (CT) scans. Furthermore, three newborns had elevated SARS-CoV-2-related immunoglobin M (IgM) antibodies, and 11 newborns (52.4%) had positive immunoglobin G (IgG) antibodies. Notably, both cystatin C and β2-microglobulin were increased in all newborns. Five of the 21 tested newborns had leukocytosis, and 11 had increased neutrophil levels. In addition, the aspartate aminotransferase of 18 newborns and the γ-glutamyl transpeptidase of 19 newborns were increased. Total bilirubin was elevated in all newborns and serum albumin was reduced in 20 of 22 newborns.

Conclusions: This study was the first to discover that COVID-19 infection in the third trimester of pregnancy could cause fetal kidney developmental injury, as indicated by increased cystatin C and β2-microglobulin in all neonates. Furthermore, there is the possibility of maternal-fetal transmission of SARS-CoV-2.