Researchers have also found that they are more likely to give birth early, as their newborns are more likely to be admitted to a neonatal unit.
An international team of researchers, including experts from the World Health Organization (WHO), reviewed evidence from 77 studies involving more than 11,000 pregnant and recently pregnant women admitted to hospital and diagnosed with Covid-19 suspected or confirmed.
Their study found that these women were less likely to report symptoms of fever and myalgia (muscle pain).
But they were more likely to need admission to an intensive care unit and need ventilation, compared to non-pregnant women of childbearing age.
Being older, overweight and having pre-existing medical conditions such as hypertension and diabetes also appear to increase the risk of having severe Covid-19 in these women, according to results published in the British Medical Journal (BMJ).
The chances of giving birth prematurely were also higher in pregnant and recently pregnant women with Covid-19 compared to those without the disease.
A quarter of all babies born to mothers with Covid-19 were admitted to a neonatal unit and were at an increased risk of admission than those born to mothers without Covid-19.
Professor Shakila Thangaratinam, WHO Collaborating Center for Global Women’s Health, Metabolism and Systems Research Institute, University of Birmingham, is leading the current review.
She explained that for every 100 pregnant women seen in hospital with Covid-19, four are admitted to intensive care and three need invasive ventilation.
She said 17% gave birth prematurely or before 37 weeks.
Professor Thangaratinam said the early births could be due to a medically dictated reason, but more research is needed to understand why.
But researchers found that ‘spontaneous premature delivery,’ where mothers just went into labor and gave birth without a decision being made, only happened 6% of the time, as in those without Covid-19.
“We also have to remember that these studies are international studies, so this could be a policy in a unit, for example, if someone has Covid at 36 weeks, they could just go ahead and deliver them,” said Professor Thangaratinam.
Research has shown that stillbirth and neonatal mortality rates are low.
Responding to mothers’ potential concerns, Prof Thangaratinam said: “I think they need to be reassured that the risk of a very bad outcome in terms of death for themselves or for the babies (is) extremely. , extremely weak. ”
She added: “We haven’t seen any major adverse outcomes for the baby, we know that a quarter of babies are admitted to… the neonatal unit… but that might just be a policy at many hospitals where they separate the baby. mother’s baby. ”
“So just an admission to the unit (doesn’t) necessarily mean that the baby has been affected, it’s just a reflection of the policy,” she said.
Pregnant women are already considered a high-risk group for severe Covid-19 infection, with concerns about the potential effects of the virus on mothers and children.
The scientists said their “living systematic review” of research in this area will be regularly updated as new evidence emerges.
The researchers acknowledged that some limitations of the study, such as differences in size, design, and symptom definition, may have affected their results, but argued that the review was reinforced by the large sample size. and robust methods.
The researchers also recommended that “mothers with pre-existing co-morbidities should be considered a high risk group for Covid-19, along with those who are obese and of an older maternal age.”