Mechanisms and evidence of vertical transmission of infections in pregnancy including SARS-CoV-2
Journal
Prenatal diagnosis
Date Issued
2020-06-12
Author(s)
Mahyuddin, A P
Kanneganti, A
Wong, Jlj
Dimri, P Sharma
Su, L L
Biswas, A
Illanes, S E
Mattar, Cnz
Choolani, M
Abstract
There remain unanswered questions concerning mother-to-child-transmission (MTCT) of SARS-CoV-2. Despite reports of neonatal COVID-19, SARS-CoV-2 has not been consistently isolated in perinatal samples thus, definitive proof of transplacental infection is still lacking. To address these questions, we assessed investigative tools used to confirm maternal-fetal infection and known protective mechanisms of the placental barrier that prevent transplacental pathogen migration. Forty studies of COVID-19 pregnancies reviewed suggest a lack of consensus on diagnostic strategy for congenital infection. While RT-PCR of neonatal swabs was universally performed, a wide range of clinical samples was screened including vaginal secretions (22.5%), amniotic fluid (35%), breast milk (22.5%) and umbilical cord blood. Neonatal COVID-19 was reported in eight studies, two of which were based on the detection of SARS-CoV-2 IgM in neonatal blood. Histological examination demonstrated sparse viral particles, vascular malperfusion and inflammation in the placenta from pregnant women with COVID-19. The paucity of placental co-expression of ACE-2 and TMPRSS2, two receptors involved in cytoplasmic entry of SARS-CoV-2, may explain its relative insensitivity to transplacental infection. Viral interactions may utilise membrane receptors other than ACE-2 thus, tissue susceptibility may be broader than currently known. Further spatial-temporal studies are needed to determine the true potential for transplacental migration. This article is protected by copyright. All rights reserved.
SDGs
Other Subjects
angiotensin converting enzyme 2 receptor; immunoglobulin M; protein; tmprss2 protein; unclassified drug; amnion fluid; blood placenta barrier; breast feeding; breast milk; coronavirus disease 2019; fetus risk; human; immunity; immunoglobulin blood level; nonhuman; placental transfer; pregnancy complication; prenatal exposure; priority journal; protein expression; real time polymerase chain reaction; Review; Severe acute respiratory syndrome coronavirus 2; umbilical cord blood; vaginal secretion; vertical transmission; virus cell interaction; virus entry; virus particle; virus transmission; female; fetomaternal transfusion; immunology; pregnancy; virology; COVID-19; Female; Humans; Infectious Disease Transmission, Vertical; Maternal-Fetal Exchange; Pregnancy; Pregnancy Complications, Infectious; SARS-CoV-2
Type
journal article