Pregnant women with COVID-19 are often asymptomatic, and nearly nine out of 10 will have only mild disease, according to a study from two New York City hospitals.

The study includes all 43 pregnant women with COVID-19 treated at Columbia University Medical Centre and New York Presbyterian Hospital between 13 March and 27 March, 18 of whom delivered babies during that time.

The authors note pregnant women were tested for COVID-19 if they had symptoms, known exposures, or recent travel. From 22 March onward, the hospitals instituted universal SARS-CoV-2 PCR testing.

Of the 43 patients, 21 were inpatients, of whom three were admitted for COVID-19 symptoms and 18 for obstetric reasons. The other 22 patients were managed on an outpatient basis.