Perinatal outcomes in new-borns of pregnant women with COVID-19: a case-control study

Abstract Background The incidence of COVID-19 vertical transmission is approximately 20%, and a shorter interval and greater maternal infection severity increase the risk of mother-to-child transmission. Objective This study aims to describe the frequency of COVID-19 positivity and clinical symptoms in newborns of pregnant women who have had COVID-19. Methods A case‒control study was carried out with unvaccinated women who had COVID-19 during pregnancy and their newborns. The 23 newborns that tested positive for COVID-19 (RT‒PCR for SARS-CoV-2) in the first 48 hours of life were matched (2:1) by day of birth and sex, with 46 other newborns that tested negative for COVID-19. The following data were collected: time and severity of maternal infection, gestational age, anthropometry, and clinical symptoms of the newborns. Results The mean age of the pregnant women was 28.50 ± 6.39 years, and the median time between COVID-19 infection and delivery was 86.0 days (26.5,179). The mean gestational age and birth weight of the newborns were 38.2 ± 1.7 weeks and 2994.2 ± 464.5 grams, respectively. Fifteen (21.7%) of the newborns experienced clinical complications during hospitalization, and the most common complications were early respiratory distress (10.1%), hypotonia/hypoactivity (13.0%), hypoglycemia (1.4%), and vomiting (1.4%). Newborns with positive RT‒PCR results for SARS-CoV-2 had a greater risk of respiratory symptoms (OR = 21.31; 95% CI 2.24 to 201.68; p = 0.008), and the likelihood of positivity in newborns increased by 0.07% (OR = 1.007; 95% CI 1.001 to 1.014; p = 0.026) for each day of COVID‒19 infection during pregnancy closer to birth. Conclusions Newborns who tested positive for SARS-CoV-2 were at greater risk of respiratory disorders, and maternal infection closer to birth increased the likelihood of positivity in newborns. There was no association between infection with COVID-19 in newborns and the severity of maternal infection, prematurity, or birth weight.