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COVID-19 vaccination associated with 15% reduction in stillbirths in pregnant women

10 May 2022

A new research paper, published today in Nature Communications*, shows that COVID-19 vaccination during pregnancy using mRNA vaccines is associated with a 15% reduction in stillbirths.

The paper also shows that vaccination in pregnancy is 90% effective against COVID-19 infection and is safe, with no increased risk in adverse outcomes for women or their babies.

The study, led by researchers from St George’s, University of London and the Royal College of Obstetricians and Gynaecologists, reviewed 23 studies including 117,552 COVID-19 vaccinated pregnant women, almost exclusively with mRNA vaccines, such as those produced by Pfizer and Moderna.

The research provides much-needed assurance to women of the safety and benefits of COVID-19 vaccination in pregnancy. Despite the fact that vaccine uptake in pregnancy in England increased from 23% in August 2021 to 53% in December 2021, nearly half of all pregnant women in the latest data have not yet received this vaccine**. One of the reasons that women often give for this hesitancy is concern about the effect of the vaccine on their baby.

Professor of Obstetrics and Maternal Medicine at St George’s, University of London and St George’s Hospital, Asma Khalil, who is the senior author on the paper, said:

“Our findings should help to address vaccine hesitancy in pregnant women.
“Although many things are returning to normal, there is still a very clear and substantial risk of COVID-19 infection for mothers and their babies, including an increased risk of premature birth and stillbirth. It is essential that as many people as possible receive their vaccines to reduce the risk of complications during pregnancy.
“This paper shows that COVID-19 vaccination is both safe and effective and we hope that this will help to reassure pregnant people to take up their offer of a vaccine going forwards.”

Dr Edward Morris, President of the Royal College of Obstetricians and Gynaecologists, said: “This paper acts as further reassurance that the COVID-19 vaccine is safe in pregnancy.

“We know women have been hesitant about having the vaccine due to concerns over the effect on their baby. We now have strong evidence to show that the vaccine does not increase the risk of adverse outcomes and is the best way of protecting both women and their babies.
“We would recommend all pregnant women have the COVID-19 vaccine and the booster vaccine. COVID-19 is still prevalent and if you do get the virus when you’re pregnant then you are at higher risk of severe illness.”

For more, please contact:

Carl Alexander, Press and Research Communications Manager at St George’s, University of London, by email, or phone, +44(0)7909 523 089.

Paper proof available on request.

- ENDS -

Notes to editors

* Prasad S. et al. (2022) Systematic review and meta-analysis of the effectiveness and perinatal outcomes of COVID-19 vaccination in pregnancy. Nature Communications.   

** COVID-19 vaccine surveillance report: week 16.

The RCOG has an extensive Q&A section for pregnant women and their families on the RCOG website:, along with a useful decision aid for women available from our Covid-19 Vaccination page.

St George’s, University of London

St George’s, University of London is the UK’s specialist health university. We are shaping modern health with transformative research, expert teaching and hands-on learning.

Our three research institutes focus on biomedical and scientific discovery, advancing the prevention and treatment of disease in the fields of population health, heart disease and infection - three of the greatest challenges to global health in the 21st century.

We provide a world-class multi-professional health sciences education that equips our graduates to meet today’s healthcare needs through relevant scientific research, clinical excellence, strong interpersonal skills and team-based working. Sharing a clinical environment with a major London teaching hospital, our innovative approach to education results in well-rounded, highly skilled clinicians, scientists, and health and social care professionals.


The Royal College of Obstetricians and Gynaecologists is a medical charity that champions the provision of women’s healthcare in the UK and beyond. It is dedicated to encouraging the study and advancing the science and practice of obstetrics and gynaecology. It does this through postgraduate medical education and training and the publication of clinical guidelines and reports on aspects of the specialty and service provision.

  • Clinical and research
  • Pregnancy and birth