Around 235 women will be given the Pfizer/BioNTech vaccine or a placebo.
The UK’s first Covid-19 vaccine study for pregnant women is set to launch.
It's taking place at 11 hospital sites in Oxford (John Radcliffe), Newcastle, Leeds, London, Gillingham, Edinburgh and Southampton.
More than 100,000 pregnant women have already been vaccinated in the US, mainly with mRNA vaccines including Pfizer/BioNTech and Moderna, with no safety concerns.
For this reason, the Joint Committee on Vaccination and Immunisation (JCVI) in the UK has said it is preferable for pregnant women in the UK to be offered the Pfizer/BioNTech or Moderna vaccines.
There is no evidence to suggest other vaccines are unsafe for pregnant women but studies are ongoing.
Participants for the new study will be identified and recruited via obstetricians and midwives at the hospital sites involved.
All women in the study will be given the Covid vaccine at some point, including those initially given a placebo.
Dr Chrissie Jones, associate professor in paediatric infectious diseases at the University of Southampton, and chief investigator for the study said: “While we have a large amount of real-world data which tells us that it’s safe for pregnant women to receive approved Covid-19 vaccines, the data gathered from a controlled research study like this is important because it will give us more information about the vaccine immune response in pregnant women, including the transfer of maternal antibodies to infants.
“All women taking part in the study will receive two doses of the approved Pfizer/BioNTech vaccine, as well as additional monitoring and support from their local research team.”
Professor Nigel Simpson, consultant obstetrician and gynaecologist at Leeds Teaching Hospital and NIHR specialty lead for reproductive health, said: “Catching Covid-19 in pregnancy can have serious consequences for mothers and their babies.
“In the future we are likely to continue living with and needing to vaccinate against Covid-19 and its variants.
“This important study will not only help us understand how best to protect the mothers and babies of today, but also how we can prepare to protect those in the future.”