Study: Most pregnant patients who tested positive for coronavirus were asymptomatic

Reviewed by Emily Henderson, B.Sc.Dec 11 2020

The majority of pregnant women who tested positive for COVID-19 on arrival to the delivery room were asymptomatic, according to a paper by Mount Sinai researchers published in PLOS One on Thursday, December 10. The pregnant patients who tested positive for the coronavirus were also more likely than those who tested negative to identify as Hispanic and report their primary language as Spanish.

In a retrospective cross-sectional study of universal screenings for SARS-Cov-2, the virus that causes COVID-19, implemented in the labor and delivery unit of Elmhurst Hospital in Queens, New York, during March and April, the researchers found that more than one-third of almost 130 pregnant women tested positive for the coronavirus.

This is a much higher proportion than reported at other hospitals in New York City during the pandemic surge, and likely related to social inequities experienced by the surrounding population. Elmhurst Hospital is a public hospital that serves a diverse, largely immigrant and low-income patient population that was severely affected by the COVID-19 pandemic in the spring. The majority, or 72 percent, of the pregnant patients who tested positive were asymptomatic, meaning they did not display any symptoms associated with COVID-19. These findings add to the evidence that there was early and rampant asymptomatic spread of the disease at a time when most community and hospital testing was limited to symptomatic individuals.

This study is instructive for other labor and delivery units and hospitals across the world as we continue to refine pandemic preparedness. In future epidemics, it may be prudent to look at labor and delivery screening numbers much earlier on, as pregnant women continue to seek essential care despite social distancing measures and also represent the general young and healthy community population."

Sheela Maru, MD, MPH, Assistant Professor of Global Health, and Obstetrics, Gynecology and Reproductive Science, Icahn School of Medicine at Mount Sinai

Dr. Maru said universal screening in the labor and delivery unit ensured safety of patients and staff during an acute surge in COVID-19 infections through appropriate identification and isolation of pregnant women with positive test results. Women were roomed by their status and were provided postpartum counseling and follow-up protocols tailored to their specific social needs.

In addition to their status for COVID-19, the study reviewed patients' demographic data including age, ethnicity, primary language, zip code, marital status, and health insurance status, and clinical data including the mode of delivery, length of stay, and comorbidities such as chronic hypertension, preeclampsia, prepregnancy obesity, asthma, diabetes, depression, and anxiety.

The study was developed through participation in the COVID-19 Unit for Research at Elmhurst (CURE-19) partnership, an initiative by Mount Sinai's Arnhold Institute for Global Health and NYC Health + Hospitals/Elmhurst to research the global pandemic and root causes of health disparities in New York City.