Adverse outcomes in SAR-CoV-2 (COVID-19) and SARS virus related pregnancies with probable vertical transmission

Abstract

The global severe acute respiratory syndrome-related coronavirus SARS-CoV-2 (COVID-19) pandemic has had an unprecedented impact on all aspects of daily life and healthcare. Information on the infection risks for pregnant women and their offspring have so far been limited to small case series, until a large UK report on 427 SARS-CoV-2 infected pregnant women was published. Previous SARS epidemic experiences were drawn upon. Diagnostic use of real time polymerase chain reaction (RT-PCR) and IgG and IgM antibody tests are fraught with concerns of non-validation and false negative results, as are sampling methodologies. Virtually no information on controls accompany these reports. Infection of the mother and baby has serious implications for obstetric and neonatal care. Information on early and late stage pregnancy infection and the relationship to severity of infection on fetal development is both useful and clearly warranted. An increasing number of reports centre around mildly infected women showing no evidence of fetal infection while a few reports suggesting vertical transmission require further validation. Vertical transmission from mother to baby however small would have profound health implications for obstetric and neonatal care and fetal abnormalities. Some data suggesting intrapartum vertical transmission from mother to baby cannot be dismissed given the lack of controls and limitations of diagnostic viral tests. This analysis covers some key early reports addressing pregnancy outcomes following SARS-CoV-2 infection.

SARS-CoV-2 ACE-receptor detection in the placenta throughout pregnancy

“…Fetal risks for women exposed to SARS-CoV-2 and subsequent pregnancy outcomes remain uncertain ( 1 ). Recent reports have raised controversial concerns regarding the potential for vertical transmission by transplacental infection.…”

Investigating the risk of maternal-fetal transmission of SARS-CoV-2 in early pregnancy

“…However, current available data from literature reviews showed that the evidence provided by the studies is poor and the vertical transmission of SARS-CoV-2 is still uncertain [ [4] , [5] , [6] ]. A meta-analysis, reviewing 38 studies, reported that viral transmission was mostly studied in neonatal nasopharyngeal swabs, and SARS-CoV-2 RNA positivity was 3,2% (22 out of 936 cases).…”

“…One of the most crucial questions about the effects of COVID-19 on pregnant women is whether the virus is passed from the mother to the fetus. The answer is still unclear, although some studies based on molecular, serological and histopathological tests on fetal-placental and neonatal tissues suggest that vertical transmission is possible [ [4] , [5] , [6] ].…”

Congenital and Intrapartum SARS-CoV-2 Infection in Neonates: Hypotheses, Evidence and Perspectives

“…The effi cacy of RT-PCR analysis of nasopharyngeal swab samples in newborns in diagnosing congenital or intrapartum infection has not yet been demonstrated. [8,13,14] The classifi cation scheme by Shah [4] makes reference to specifi c clinical manifestations of SARS-CoV-2 infection, but the clinical presentation of COVID-19 in newborns is still poorly understood, and both clinical markers and imaging fi ndings remain nonspecifi c.…”

“…[69,70] Aspiration of amniotic fl uid or maternal blood at birth has also been considered. [8,14] Epidemiological studies have not demonstrated increased risk of miscarriage for COVID-19-positive women. [29] Placental changes consisting of defects in the proliferation and formation of chorionic villi, typical of early stages of pregnancy, occur in a similar proportion to the rate of SARS-CoV-2 infections in the fi rst trimester of pregnancy, which might suggest a correlation between these two rare phenomena.…”