A new study from the COVID Symptom Study app, shows that healthy pregnant women do not differ in how severely they are likely to fall ill from COVID-19 compared with non-pregnant women.

Since the beginning of the pandemic there have been concerns that pregnancy puts people at greater risk from coronavirus, although other studies to date have only focused on people hospitalised with COVID-19 rather than those who are less severely ill within the community

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.‍

Marc Modat, Senior Lecturer at King’s College London who worked on the study commented:

“Our study highlights the power of gathering and analysing large-scale health data to understand how COVID-19 affects different groups within the population. We need to encourage as many people as possible to use simple health technology like the COVID Symptom Study app to shed light on this new disease and monitor its progress over the months ahead.”‍

King's College London MRC Research Fellow, Dr Erika Molteni, who also worked on the study, added:

“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”

The findings from the study are available online as a pre-print (Erika Molteni et al. SARS-CoV-2 (COVID-19) infection in pregnant women: characterization of symptoms and syndromes predictive of disease and severity through real-time, remote participatory epidemiology (2020) medRxiv DOI: 10.1101/2020.08.17.20161760) and have been submitted to a scientific journal for peer review and publication. ‍

About The COVID Symptom Study app

The COVID Symptom Study app is a not-for-profit initiative that was launched at the end of March 2020 to support vital COVID-19 research. The app was launched by health science company ZOE with scientific analysis provided by King’s College London. With 4 million contributors globally, the Study is the world’s largest ongoing study of COVID-19 and is led by ZOE Co-Founder and King’s College Professor, Tim Spector. The team has published over 15 research papers since March, most notably in Nature Medicine.

To date the app has been funded by ZOE and generous donations from app contributors. On 19 August 2020, the Department of Health and Social Care announced that it has awarded the COVID Symptom Study app £2million in funding. The funding was awarded to enable the app to continue collecting data from its 4million + users to facilitate hotspot detection and scale-up testing programmes with the ONS. The app provides unique insight on asymptomatic and symptomatic information across the UK with 1.2 million logging on a weekly basis.For more information on The COVID Symptom Study app visit covid.joinzoe.com. 

About ZOE

ZOE is a healthcare science company using data-driven research to tackle the world’s health issues. By using machine learning combined with digital technologies like mobile phones, ZOE enables large-scale scientific studies to tackle issues like COVID-19, inflammation and the impact of nutrition on health. 

Located in London and Boston, ZOE was founded by Professor Tim Spector of King’s College London, machine learning leader Jonathan Wolf and entrepreneur George Hadjigeorgiou. ZOE has carried out the largest nutritional studies of their kind in the world, and was named one of the Deloitte Fast 50 Rising Stars in 2019 for the company’s contribution to science enabled by technology and machine learning. 

For more information on ZOE’s mission and science visit joinzoe.com. Join the waitlist for updates about ZOE products and research studies at joinzoe.com/signup Find us on Instagram @ZOE

About King’s College London

King's College London is one of the top 10 UK universities in the world (QS World University Rankings, 2018/19) and among the oldest in England. King’s has more than 31,000 students (including more than 12,800 postgraduates) from some 150 countries worldwide, and some 8,500 staff.

King's has an outstanding reputation for world-class teaching and cutting-edge research. In the 2014 Research Excellence Framework (REF), eighty-four per cent of research at King’s was deemed ‘world-leading’ or ‘internationally excellent’ (3* and 4*).  

Since our foundation, King’s students and staff have dedicated themselves in the service of society. King’s will continue to focus on world-leading education, research and service, and will have an increasingly proactive role to play in a more interconnected, complex world. Visit our website to find out more about Vision 2029, King’s strategic vision for the next 12 years to 2029, which will be the 200th anniversary of the founding of the university.  

World-changing ideas. Life-changing impact. Kcl.ac.uk