Significance of placental swab in diagnosing vertical transmission in SARS-CoV-2 positive mothers.

Abstract

AimsCurrently, there is limited date on the effects of COVID-19 on pregnancy and neonatal outcome. This literature review aims to investigate the possibility of fetal vertical transmission in COVID-19 positive pregnant mothers by diagnosing through placental swabs.MethodsThe search terms ‘pregnant COVID-19 positive mothers’, ‘fetal vertical transmission’ and ‘placental swabs’ were used. 11 papers were selected for this review.ResultsThis literature review comprises 45 COVID-19 positive pregnant women whose placentas and neonates were also analysed by RT-PCR for the presence of SARS-CoV-2. 43 neonates were successfully delivered primarily via caesarean section out of 45 expectant mothers (96%). 2 mothers did not deliver due to severe preeclampsia and a miscarriage both occurring in the second trimester. 3 neonates tested positive for SARS-CoV-2 (7%). We report no neonatal mortality after birth and no maternal mortality. 8 female’s placentas tested positive for SARS-CoV-2 out of a total of 45 tested (18%). Of these 8, 2 cases of SARS-CoV-2 were identified in the maternal, neonatal and placental tissue.ConclusionAfter reviewing multiple studies and investigating the nature of placental physiology in SARS-CoV-2 positive mothers we conclude that there is no concrete evidence of vertical transmission occurring between mother and infant. However, there are inconsistencies across the different papers used for this review and further research investigating the effects of COVID-19 on pregnant women by using RT-PCR to test the mother, placenta, vaginal fluid, breast milk and infant for SARS-CoV-2 at various stages of transmission is urgently needed.