King's College London

For this study, the researchers focused on two groups of pregnant woman - the first drawn from 4 million UK and 50,000 Swedish users of the COVID Symptom Study app and the second from nearly 1.9 million women aged 18-44 who responded to the US-based Facebook COVID-19 Symptom Survey, hosted by the Carnegie Mellon Delphi Research Center.

In the first group, the researchers analysed self-reported health data from around 14,000 pregnant women using the COVID Symptom Study 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, the team 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, compared with 4% of the non-pregnant women.

The most common symptoms for pregnant women were 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 group of pregnant women who became most severely ill with COVID-19, which could be confused with similar symptoms that are due to the pregnancy itself.

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, in the absence of any other underlying health problems.

Pregnant women with existing health conditions, such as lung, heart or kidney disease and diabetes, were more likely to end up in hospital with COVID-19, similar to what has been seen for comparable groups in the general population.

MRC Research Fellow, Dr Erika Molteni from the School of Biomedical Engineering & Imaging Sciences said: “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. 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.”