Pregnant women who are infected with COVID-19 are more at risk for severe illness than other women who have the virus, a CDC study released Thursday has found.

The analysis determined that pregnant women with COVID had higher rates of hospitalization and increased risk for ICU admission and need for mechanical ventilation. The risk of death was the same for pregnant women and non-pregnant infected women.

“To me, this is the most compelling evidence to date that pregnant women are at increased risk,’’ said Dr. Denise Jamieson, chair of the Department of Gynecology and Obstetrics at Emory University School of Medicine.

The study is based on data from thousands of women with confirmed infections of COVID-19 as reported to the CDC from Jan. 22 to June 7.

More than 31 percent of the pregnant women were hospitalized, compared with about 6 percent of women who were not pregnant.

“It’s going to be really important for us going forward to counsel our pregnant patients to avoid infection,’’ Jamieson said. That includes staying home, wearing a mask and following social distancing guidelines, she told reporters Thursday.

A study in Sweden, though smaller, had similar findings. Pregnant women with COVID-19 were five times more likely to be admitted to the ICU and four times more likely to receive mechanical ventilation than were non-pregnant women.

Pregnant women should not be excluded from vaccine trials, Jamieson said.

The CDC report did not address the medical outcomes for the newborns.

The risk of pre-term birth may be higher for infected women, Jamieson said.

“In my opinion, pregnant women should be classified as a higher-risk group’’ for COVID complications, along with people with existing medical conditions and the elderly, she said.

The study also found that Hispanic and black pregnant women appear to be disproportionately affected by COVID-19 during pregnancy. Both groups in general have had disproportionately high infection rates during the pandemic.

The new study did not include one pivotal detail: whether the pregnant women were hospitalized because of labor and delivery. It that was the case, it may have significantly inflated the numbers, so it is unclear whether the analysis reflects a true increase in risk of hospitalization, the New York Times reported.

Pregnancy transforms the body’s biology, ramping up metabolism, blood flow, lung capacity and heart rate. It also suppresses a woman’s immune system to accommodate the fetus — a circumstance that can increase the woman’s susceptibility to respiratory illnesses like influenza, the Times added.