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Universal testing for coronavirus disease 2019 in pregnant women admitted for delivery: prevalence of peripartum infection and rate of asymptomatic carriers at four New York hospitals within an integrated healthcare system

Our take —

This study objective was to describe the prevalence of SARS-CoV-2 among pregnant women presenting to the hospital for delivery. Using universal testing, 375 women were tested for infection across four hospitals, of which 71 tested positive (18.6%), and 64 of those were asymptomatic (70.3%). Although recall bias related to earlier symptoms may lead to some misclassification between symptomatic vs. asymptomatic cases, the majority of women with SARS-CoV-2 infections detected were asymptomatic despite pregnancy-related immunosuppression. This study highlights the need for greater testing in hospital settings serving pregnant people at delivery.

Study design

Retrospective Cohort

Study population and setting

The primary study objective was to examine whether the risk of SARS-CoV-2 infection was associated with prior COVID-19 signs and symptoms among peripartum women. 403 women admitted for delivery across 4 hospitals in New York between April 2 and April 9, 2020 who were potentially eligible for enrollment. Women were excluded for antepartum admissions where no delivery occurred and postpartum readmissions, for a total eligible cohort of 382, of whom 375 were tested under the universal testing protocol. Specimens were obtained within 1 hour of hospital admission, or within 48 hours of admission for scheduled cesarean or induction, and tested for SARS-CoV-2 via RT-PCR tests. Clinical and laboratory data were extracted from electronic medical records (EMRs) and reviewed manually for history of COVID-19 signs and symptoms.

Summary of Main Findings

Of the 375 women tested for SARS-CoV-2, 64 newly tested positive (17.1%), and 7 were previously tested and diagnosed. Thus, the overall prevalence was 18.6% (71/375 women). 64 of those testing positive were asymptomatic (70.3%). The most common symptoms reported among symptomatic patients were cough (57.9%, 11 of 19 symptomatic patients), fever (52.6%, 10 patients) and dyspnea (47.4%, 9 patients). Maternal age and race/ethnicity varied between the four sites, with non-Hispanic white women making up 42.2% of the overall cohort (N=156), followed by Hispanic/Latina women (19.5%, N=72). PCR positive tests also varied between sites, with Southside Hospital reporting the highest prevalence (28.8%, 15 of 52 patients), and North Shore University Hospital representing the lowest (8.8%, 11 of 128 patients).

Study Strengths

The study used a universal testing protocol which was able to identify both symptomatic and asymptomatic patients. It also included all women who delivered at any of the four hospitals, which likely results in a representative sample that may be generalizable to other populations with similar demographics. Using chart review, they were able to capture signs and symptoms based on medical examinations, as opposed to recall alone, which may have resulted in more valid classification.

Limitations

The study used electronic medical records, which may or may not have always taken comprehensive symptom assessments in a structured format, and therefore may be subject to limitations based on what information was previously collected. Participants may have potentially over-reported symptoms out of an abundance of caution, which would lead to an over-estimation of the number of symptomatic cases. The authors also mention women may not have reported symptoms due to fears around COVID-19 diagnosis during this time, which would lead to an underestimation in the number of symptomatic cases. Misclassification from self-report could lead to bias in either direction. Also, these results reflect active COVID-19 infection at delivery, and does not show prior infection among pregnant women.

Value added

This paper estimates the prevalence of infection among pregnant people presenting at hospitals for delivery, providing important information for providers and hospital infection control.

This review was posted on: 24 September 2020