Forest plot of studies reporting stillbirth rate. Vertical ticks within the blue boxes and horizontal lines show the mean effect and 95% confidences interval for each study. Black diamond at the bottom shows the cumulative effect with 95% confidence intervals. Credit: Nature Communications (2022). DOI: 10.1038/s41467-022-30052-w

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 Gynecologists, 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 . 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 Gynecologists, 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 and their babies. We would recommend all have the COVID-19 vaccine and the booster . 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."

More information: Smriti Prasad et al, Systematic review and meta-analysis of the effectiveness and perinatal outcomes of COVID-19 vaccination in pregnancy, Nature Communications (2022). DOI: 10.1038/s41467-022-30052-w

Journal information: Nature Communications