Healthy pregnant women are not at higher risk of falling seriously ill from COVID-19 than healthy women not pregnant, suggests a study from King's College London.

The observational study focused on two groups of pregnant women – the first taken from 4 million UK and 50,000 Swedish users of the COVID Symptom Study app, and the second from around 1.9 million women aged 18-44 who responded to the US-based Facebook COVID-19 Symptom Survey.

Researchers analysed self-reported health data from around 14,000 pregnant women using the app, of whom 629 were likely to have COVID-19 based on their symptoms and 21 were hospitalised. They compared this with data from 387,000 non-pregnant female app users, where just over 25,000 were suspected to have the disease and nearly 600 ended up in hospital.

For the second group, they looked at around 1.3 million survey responses from women, including nearly 42,000 from those who said they were pregnant. Just 2.9% of the pregnant respondents were suspected to have COVID-19 versus 4% of the non-pregnant women.

The most common symptoms experienced by pregnant women were found to be similar to non-pregnant people, including persistent cough, headache, loss of taste or smell (anosmia), chest pain, sore throat and fatigue.

However, there was an increased incidence of gastrointestinal symptoms such as nausea and vomiting in the subset of pregnant women who became most severely ill with COVID-19, which the researchers note could be confused with similar symptoms due to pregnancy itself.

The researchers found that although pregnant women reported being tested more frequently for coronavirus, they were no more likely to suffer severe symptoms of COVID-19 or be ill for longer than those who weren’t pregnant, if otherwise healthy.

Pregnant women with underlying health conditions were more likely to end up in hospital with COVID-19, but this was found to be at a similar rate to what has been observed for comparable groups in the general population, the researchers note.

“Although our findings should be reassuring for healthy women who are pregnant at this time, it highlights the importance of protecting those with underlying health conditions and keeping a close eye on them during their pregnancy, particularly if they start showing symptoms of COVID-19,” said MRC Research Fellow, Dr Erika Molteni from the School of Biomedical Engineering & Imaging Sciences.

“It’s vital that we all keep taking steps to protect the health of everyone in our communities by sticking to social distancing guidelines, wearing face coverings in public and following good hand hygiene practices.”