There is also evidence that the Delta variant poses a significantly greater risk than all other previous strains of the virus.
Around 200 pregnant women were admitted to hospital with Covid-19 last week.
The Royal College of Obstetricians and Gynaecologists and the Royal College of Midwives recommend that unvaccinated women who are pregnant or considering pregnancy get their vaccine as soon as possible, and book their second doses once they are eligible.
Covid-19 poses significant risks to both mother and baby. Pregnant women are particularly vulnerable to becoming severely ill from Covid-19.
Around one in 10 pregnant women admitted to hospital with symptoms require intensive care, and one in five gives birth prematurely.
New data from the UK Obstetric Surveillance System (UKOSS), published on medRxiv, show that COVID-19 vaccinations offer effective protection from these risks.
According to the latest analysis of data on all pregnant women admitted to hospital with confirmed Covid symptoms in the UK - from the start of the pandemic up until 11 July - more than 99 per cent of pregnant women admitted to hospital with symptomatic Covid-19 are unvaccinated.
In comparison, 60 per cent of the general population admitted to hospital with Covid are unvaccinated.
The data shows:
- 3,371 pregnant women have been admitted to hospital with symptomatic Covid-19.
- The severity of women’s illness appears to have become worse; 24 per cent of women admitted in the first wave had moderate or severe disease, compared with 36 per cent with the Alpha variant and 45 per cent with the Delta variant.
- Vaccination data has been collected since 1 February 2021. Of 742 women admitted since that date, only four have received a single dose of vaccine and none have received both doses.
The study was funded by the National Institute for Health Research (NIHR).
Marian Knight, professor of maternal and child population health at the Nuffield Department of Population Health, University of Oxford and chief investigator of the study, said, ‘It is extremely good news that so few vaccinated pregnant women have been admitted to hospital with Covid-19. However, it is very concerning that admissions of pregnant women to hospital with Covid-19 are increasing and that pregnant women appear to be more severely affected by the Delta variant of the disease.
‘I cannot emphasise more strongly how important it is for pregnant women to get vaccinated in order to protect both them and their baby. Until they are vaccinated, pregnant women must continue to be extremely attentive to social distancing measures including mask wearing, 2m distancing and meeting outdoors where possible.’
Since the start of the pandemic, at least 55,000 pregnant women have received one or more doses of a Covid vaccine in the UK. Worldwide more than 200,000 pregnant women have now received a Covid vaccine.
Nicola Vousden, registrar in Public Health at the Nuffield Department of Population Health and the first author of the study, said, 'This study shows that very few pregnant women are admitted to hospital with Covid-19 after they have received a vaccine. Other studies have shown that women who have received a vaccine pass on antibodies to their babies, so the benefits of vaccination to both pregnant women and their babies are clear.’
