LONDON (Reuters) - Pregnant women are no more likely to become severely ill with COVID-19 than other women, according to a preliminary study in Britain, but most expectant mothers who do develop serious illness tend to be in the later stages of pregnancy.
The study looked at 427 pregnant women who were admitted to hospital with COVID-19, the lung disease caused by the new coronavirus, between March 1 and April 14.
It found fewer than 0.5 percent of all pregnant women were admitted to hospital with the disease, and only around 1-in-10 of those needed intensive care.
This suggested that mothers-to-be are at no greater risk of severe COVID-19 than the wider population, said the research team led by Oxford University and Britain’s Royal College of Obstetricians and Gynaecologists.
“(However) most pregnant women who were admitted to hospital were more than six months pregnant, which emphasises the importance of continued social distancing measures in the later stages of pregnancy,” said Marian Knight, an Oxford professor of maternal and child population health who co-led the work.
A separate study from Sweden which analysed 53 expectant mothers suggested that compared to non-pregnant women with COVID-19, similarly aged pregnant women with the disease were more than five times as likely to need intensive care.
In an editorial comment on these findings, published on Sunday in the medical journal Acta Obstetricia et Gynecologica Scandinavica, experts said women should “be advised to take necessary precautions to avoid infection during pregnancy”.
The UK study, which was not peer-reviewed but posted online on Monday on the MedRxiv website, found that pregnant women from minority ethnic groups and those who were overweight or had other health conditions, such as high blood pressure and diabetes, were more likely to be need hospitalisation.
“A very small number of pregnant women do become severely ill with COVID-19 and sadly some women have died,” Knight said in a statement about the study’s findings.
“It is concerning that more pregnant women from black and minority ethnic groups are admitted with COVID-19 in pregnancy and this needs urgent investigation.”
Analysing the outcomes for babies born to mothers with COVID-19, the researchers said they were “largely reassuring”.
Although almost one-in-five were born prematurely and were admitted to a neonatal unit, fewer than 20 babies in the sample studied were born at less than 32 weeks gestation, they said.
One-in-20 born to the mothers in the study tested positive for COVID-19, but only half of these positive tests were immediately after birth. This suggests transmission of infection from mother to baby is low, the researchers said.
Andrew Shennan, a professor of obstetrics at King’s College London who was not directly involved in either study, said the UK research, was the “most systematic look” so far at pregnancy outcomes in COVID-19 patients.
“Pregnant women can be reassured by this,” he said. “The outcomes are excellent for the baby, with 97% live births, very similar to a control group (and) the chance of serious problems to the mother are very similar to non-pregnant populations.”
Reporting by Kate Kelland; Editing by Alex Richardson and Chizu Nomiyama