Routine screening for SARS CoV-2 in unselected pregnant women at delivery

Abstract

Background South America has become the epicenter of coronavirus pandemic. It seems that asymptomatic population may contribute importantly to the spread of the disease. Transmission from asymptomatic pregnant patients' needs to be characterized in larger population cohorts and symptom assessment needs to be standardized. Objective To assess the prevalence of SARS CoV-2 infection in an unselected obstetrical population and to describe their presentation and clinical evolution. Methods A cross-sectional study was designed. Medical records of pregnant women admitted at the Obstetrics & Gynecology department of Clínica Dá vila for labor & delivery, between April 27 th and June 7 th , 2020 were reviewed. All patients were screened with RT-PCR for SARS CoV-2 at admission. After delivery, positive cases were inquired by the researchers for clinical symptoms presented before admission and clinical evolution. All neonates born from mothers with confirmed SARS CoV-2 were isolated and tested for SARS CoV-2 infection. Results A total of 586 patients were tested for SARS CoV-2 during the study period. Outcomes were obtained from 583 patients which were included in the study. Thirty-seven pregnant women had a positive test for SARS CoV-2 at admission. Cumulative prevalence of confirmed SARS CoV-2 infection was 6.35% (37/583) [CI 95%: 4.63-8.65]. From confirmed cases, 43.2% (16/37) were asymptomatic. From symptomatic patients 85.7% (18/21) had mild symptoms and evolved without complications and 14.3% (3/21) presented severe symptoms requiring admission to intensive care unit. Only 5.4% (2/37) of the neonates born to mothers with a positive test at admission had a positive RT-PCR for SARS CoV-2.

The Proportion of SARS-CoV-2 Infections That Are Asymptomatic

“…We summarize the evidence in terms of the number of studies and the range, median, and interquartile range (IQR) for persons who tested positive but had no symptoms at the time of PCR testing or who reported having had no symptoms before or at the time of antibody testing. Thirty of the studies included a list of specific symptoms, independent of signs, used to determine symptomatic status ( 10–14 , 17 , 18 , 22–28 , 35 , 36 , 38 , 42 , 49 , 51 , 55–57 , 60–62 , 64 ). Many of the remaining studies used some variation of the catch-all phrase “symptoms compatible with COVID-19.”…”

Screening of severe acute respiratory syndrome coronavirus-2 infection during labor and delivery using polymerase chain reaction and immunoglobulin testing

“…The maternal and neonatal clinical course of our studied population showed similar maternal and perinatal outcomes when comparing women with and without SARS-CoV-2 infection. Previous studies using only PCR testing during labor and delivery, in both symptomatic and asymptomatic COVID-19 patients, reported high rates of cesarean delivery among these women [ 15 , 16 ]. In a series of 675 pregnant women from New York admitted for labor and delivery, Prabhu et al [ 15 ] reported a slight increase in the rate of cesarean delivery in symptomatic COVID-19 women (46.7%) compared to asymptomatic ones (45.5%).…”

“…In a series of 675 pregnant women from New York admitted for labor and delivery, Prabhu et al [ 15 ] reported a slight increase in the rate of cesarean delivery in symptomatic COVID-19 women (46.7%) compared to asymptomatic ones (45.5%). Díaz-Corvillón et al [ 16 ] in Chile described another study for SARS-CoV-2 in 583 patients using only PCR during labor and delivery admission. They reported a 43.2% rate of asymptomatic women and no significant differences in perinatal outcomes, but a trend towards a higher rate of preterm birth.…”

“…Thus, Prabhu et al [ 15 ], in New York, described a mild course of COVID-19 disease among their cohort of 675 pregnant women, with only one case of admission to the maternal ICU. In Chile, Díaz-Corvillón et al [ 16 ] reported a 0.51% admission rate to the maternal ICU and mechanical ventilation. In our study, we did not have severe COVID-19 cases.…”

“…Moreover, mixed consolidation and complete consolidation were common among laboratory-confirmed cases [ 3 ]. High asymptomatic rates (43–88%) have also been demonstrated among pregnant women admitted for labor and delivery [ 11 , [14] , [15] , [16] , [17] ], resembling rates in the non-pregnant population (86%) [ 18 ]. The main diagnostic tool for the detection of ongoing infection with SARS-CoV-2 has been polymerase chain reaction (PCR).…”