A systematic evaluation of the mother-to-child transmission potential of
SARS-CoV-2 infection during pregnancy
Objective This study aimed to comprehensively evaluate the clinical
characteristics of COVID-19 in perinatal period, and systematically
assess the mother-to-child transmission potential of SARS-CoV-2. Design
A case retrospective study. Setting and Population We retrospectively
analyzed the data of 23 pregnant patients in late pregnancy. Methods
Maternal and neonatal throat swabs, vaginal secretions, placenta
tissues, and breast milk, were collected for the nucleic acid test of
the virus. Pregnancy outcomes and neonatal results were also analyzed.
Main Outcome Measures The result of viral nucleic acid test and
pregnancy outcomes. Results Overall, 10 patients (43.5%) had no
symptoms and were found by routine chest CT. Complications appeared
after COVID-19 onset included PROM (17.4%) and fetal distress (4.3%).
Typical signs of viral pneumonia were recorded in chest CT of all
patients. No patients developed severe pneumonia or died of COVID-19.
All of 25 neonates were born alive. No severe asphyxia or neonatal death
was observed. Although three neonates were tested transiently suspected
positive for SARS-CoV-2 after being transferred to neonatology
department, no newborns developed COVID-19. Only a rectal swab sample
from one pregnant patient was tested positive for SARS-CoV-2, while all
the other clinical specimens including first sample of newborn throat
swabs were negative. Pathological examination found no obvious
chorioamnionitis or clear virus inclusion body in placenta, and ACE2
(angiotension-converting enzyme 2) was expressed at a moderate level.
Conclusions Asymptomatic patients were present in pregnant women. There
is no confirmatory evidence for mother-to-child transmission in COVID-19
patients with late pregnancy.