Pregnant women with Covid-19 are less likely to have symptoms, and may be more likely to give birth early, new research shows.

Compared with non-pregnant women of a similar age, researchers found pregnant and recently pregnant women with Covid-19 were less likely to report symptoms of fever and muscle pain (myalgia), but were more likely to need admission to an intensive care unit and need ventilation.

The study, published in the BMJ, found a quarter of all babies born to mothers with Covid-19 were admitted to a neonatal unit and were at increased risk of admission than those born to mothers without the disease. However, stillbirth and newborn death rates were low. 

The odds of giving birth prematurely was also higher in pregnant and recently pregnant women with Covid-19, compared to those without the disease. 

Pregnant women are thought to be a high-risk group for Covid-19, but reviews on Covid-19 in pregnancy quickly become outdated as new evidence emerges. So, a team of researchers began a review to compare the outcomes of Covid-19 in pregnant and recently pregnant women, with non-pregnant women of a similar age.

Their findings are based on 77 studies and outcomes for 11,432 pregnant and recently pregnant women admitted to hospital and diagnosed as having suspected or confirmed Covid-19.

Maternal risk factors associated with severe Covid-19 were found to be increasing age, high body mass index, chronic high blood pressure, and pre-existing diabetes.

The researchers point to some study limitations that may have affected their results, but say healthcare professionals should be aware pregnant women with Covid-19 might need access to intensive care and specialist baby care facilities.

Mothers with pre-existing conditions will also need to be considered a high risk group for Covid-19, along with those who are obese and of older age, they add.

Dr Edward Norris, president of the Royal College of Obstetricians and Gynaecologists, calls the study a “welcome and comprehensive synthesis of the available research on Covid-19 in pregnancy”. 

“This study highlights a possible increase in the need for intensive care among pregnant women with coronavirus,” he tells HuffPost UK. “This is also true for pregnant women should they contract flu. This year, it’s particularly important pregnant women take up the offer of the free flu vaccine, which is safe in all trimesters of pregnancy, to protect them from becoming seriously unwell.”

Dr Norris added that the findings of this paper highlight the “need for more research into the ​effects of the virus on pregnant women and their babies” in order for health services to better respond to their needs.