Intrauterine vertical transmission of SARS-CoV-2 infection: A single-center experience

INTRODUCTION The effects of the Coronavirus disease in pregnancy are yet unknown, despite the increasing data coming from scientific literature. The aim of this study is to assess the probability of intrauterine vertical transmission in pregnant women affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. METHODS We conducted a retrospective observational study on pregnant women, affected by a confirmed SARS-CoV-2 infection, who were admitted to our tertiary Department of Gynecology and Obstetrics in San Marco Hospital, between March 2020 and March 2021. The probability of intrauterine vertical transmission was evaluated through COVID-19 Time Quantitative Reverse Transcription PCR (qRT-PCR) test on amniotic fluid, placenta, cord blood, neonatal nasal and rectal swab samples. RESULTS The study population included 110 pregnant women affected by SARS-CoV-2 infection. Most of them (68%) had a caesarean section in the third trimester. Among all these patients, 42 patients (38%) were asymptomatic, while 68 women (62%) showed symptoms, such as asthenia (35 patients;31%), fever (19 patients;17%), cough (16 patients;14%) and myalgia (8 patients;7%). Twenty-two patients (20%) had a previous history of respiratory disease and 35 (32%) smoked before or during pregnancy. None of the women or newborns died or developed severe pneumonia. However, two male newborns were positive for SARS-CoV-2 infection by nasopharyngeal and rectal swabs, performed at 1 h and 24 h of life. Both labors were spontaneous and women delivered vaginally, without evidence of intra-partum fetal distress. The weights at birth were 3060 gr at 38° week of gestation and 3400 gr at 40° week, respectively;Apgar index was 9-10 in both cases at 1 and 5 min. Moreover, the first baby showed pH of 7.29, pCO2 of 45mmHg and pO2 10.1mmHg, while the second baby had pH of 7.32, pCO2 of 49mmHg and pO2 and 18.4mmHg. They exhibited good conditions and they were asymptomatic during the hospital stay in rooming-in regimen. After three days of life, they were tested again for SARS-CoV-2 through nasopharyngeal and rectal swabs, without evidence of neonatal infection or COVID-19 symptoms. Moreover, all samples of amniotic fluid, cord blood, foetal and maternal placental sides resulted negative. CONCLUSIONS Findings from this small number of patients suggest that the probability of intrauterine vertical transmission of SARS-CoV-2 infection is rare and the neonatal outcomes is favorable. In the next future, larger studies are needed in order to confirm our results.