Few asymptomatic pregnant women test positive for SARS-CoV-2
Less than 3% of asymptomatic pregnant women who presented for childbirth at one of three hospitals in southern Connecticut tested positive for SARS-CoV-2, according to a research letter published in JAMA.
Despite the low prevalence, researchers recommended a “rationalized approach” to the use of personal protective equipment (PPE) in obstetric units.
Katherine Campbell, MD, MPH, medical director, Yale New Haven Hospital Labor & Birth and Maternal Special Care Units, and colleagues conducted SARS-CoV-2 screening and testing in 782 pregnant women who presented for childbirth at one of three hospitals within the Yale New Haven Health system in southern Connecticut from April 2 to April 29. In the cohort, 1.5% were previously diagnosed with COVID-19. Of the remaining 770 patients, 3.9% tested positive for SARS-CoV-2. Moreover, 73.3% of patients who tested positive upon arrival were asymptomatic.
Campbell and colleagues wrote that the overall prevalence of positive test results among 756 asymptomatic patients was 2.9%. The prevalence of positive test results among those patients increased from 0.6% to 5% from the first 2 weeks of the study to the second 2 weeks. However, the prevalence of symptomatic patients who tested positive in the total population admitted for childbirth decreased from 1.4% to 0.7%. Of the 14 patients with viral symptoms, 57% tested positive for SARS-CoV-2. Researchers also reported that no asymptomatic patients who tested negative developed symptoms or needed additional testing.
“Unlike other studies, we were able to show a change in the characteristics of our patients who are testing positive for SARS-CoV-2,” Campbell said. “While we noted an increase in the number of asymptomatic women testing positive over the two time periods, we saw a decrease in the number symptomatic COVID-19 infections over the same time periods. We hypothesize universal testing for SARS-CoV-2 may identify patients in the convalescent, non-infectious period in addition to those with a subclinical active infection.
The hospitals’ policies recommended universal mask use by both clinicians and patients, the researchers said. Clinicians who managed patients with COVID-19 symptoms and patients who later tested positive for the disease wore N95 respirators and appropriate PPE until test results returned, and they continued to wear respirators and PPE if the results were positive. Clinicians who managed asymptomatic patients also wore masks. For the second stage of labor and cesarean or vaginal birth, clinicians wore full PPE and N95 respirators if they managed patients who did not have SARS-CoV-2 test results or tested positive for the disease.
Researchers reported that none of the participating health care workers in the obstetric units were removed from work due to SARS-CoV-2 exposure or disease from transmission from a known or possible contact with a patient.
Campbell cautioned that the approach her colleagues took may not be universally applicable.
“Testing policies should be very local decisions that account for local testing supplies, performance characteristics of the available tests, the amount of PPE and local disease prevalence and trends.”