This study describes the prevalence of positive SARS-CoV-2 test results among asymptomatic pregnant women presenting for labor and delivery at Yale New Haven health system hospitals. Findings suggest a low (<3%) prevalence of positive SARS-CoV-2 test results among asymptomatic patients in a pregnant population.
From April 2 to April 29, 2020, 3 Yale New Haven Health hospitals in southern Connecticut initiated screening and testing of patients admitted for childbirth. Screening consisted of questions related to travel, contacts, and symptoms of COVID-19. All patients without a prior diagnosis of COVID-19 underwent SARS-CoV-2 polymerase chain reaction (PCR) testing.
782 patients were screened during this time frame; 1.5% (12/782) were previously diagnosed with COVID-19. The remaining 770 patients were tested at admission and 30 (3.9%) tested positive for SARS-CoV-2. Twenty-two of the 30 who tested positive for SARS-CoV-2 (73.3%) were asymptomatic. The overall prevalence of positive test results among asymptomatic patients was 2.9% (22/756).
Prevalence of positive test results among asymptomatic patients increased from 0.6% (2/355) to 5% (20/401) from the first 2 weeks (April 2-15, 2020) to the second 2 weeks (April 16-29, 2020), though the prevalence of symptomatic patients who tested positive in the total population admitted for childbirth decreased from 1.4% (5/365) to 0.7% (3/405). Fifty-seven percent (8/14) of patients with symptoms tested positive. No asymptomatic patients who tested negative developed symptoms or required further testing. No health care workers on 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.