Large UK study finds that COVID-19 may increase the risk of stillbirth and premature birth

A large UK study suggests having coronavirus at birth may increase the chance of stillbirths and premature births, although this risk remains low.

The research, led by the National Maternity and Perinatal Audit, looked at data from more than 340,000 women who gave birth in England between the end of May 2020 and January 2021. The study appears in the American Journal of Obstetrics and Gynecology.

It's really important to remember that the scientists who did the research have said that despite the increased risk of stillbirth and premature birth for women who have COVID-19 in pregnancy, this risk remains low. 

All women were tested for the virus when they were admitted for births, whether they had symptoms or not.

The study found that 3,527 of these women had positive COVID-19 tests. This was more common in women who were younger and from a black, Asian or other minority ethnic background.

The scientists calculated that:

  • 8.5 per 1,000 women who had a positive test went on to experience a stillbirth, compared to 3.4 per 1,000 women who had a negative test.
  • 12% of women who had a positive coronavirus test gave birth prematurely, compared to 5.8% of women who had negative tests.

Researchers also found that:

  • women had a higher risk of stillbirth, prematurity and a caesarean section, regardless of their age, ethnicity, socio-economic background and common health conditions.
  • Babies born to women who tested positive were more likely to need treatment in the neonatal intensive care unit because they were born early and needed more support, rather than being infected with coronavirus itself.

Professor Jan van der Meulen, Professor of Clinic Epidemiology at the London School of Hygiene and Tropical Medicine and co-lead author on the paper, said:

“It’s important we interpret these findings with caution, as we only have information about COVID-19 infection at the time of birth. It is possible that our results can be partly explained by differences in infection rates during different periods of pregnancy: women towards the end of their pregnancy may have been less likely to catch the virus than women earlier in pregnancy, as advice to women and to their employers has focused on the risks of COVID in late pregnancy after 28 weeks gestation."

Professor Alexander Heazell, Director of Tommy’s Maternal and Fetal Health Research Centre at St Mary’s Hospital in Manchester said:

"We still need a bigger picture from longer-term analysis before we can understand the national or global impact of Covid-19 – and unfortunately it’s too early to see that yet. The pandemic is still unfolding, and solid research evidence takes time to develop. Our research suggests the virus doesn’t usually cross the placenta, and doesn’t appear to be directly related to stillbirth; any change in stillbirth rates could be due to changes in the care system, which is why it’s so important that expectant parents keep going to their appointments and seek help for worrying symptoms like reduced baby movements. There are a lot of questions right now, but Tommy’s is collaborating with scientists across the world to find the answers.”

Dr Mary Ross-Davie, at the Royal College of Midwives, said:

"While the increased risk of a stillbirth or pre-term birth remains low when women have COVID-19 in pregnancy, the important message here is that pregnant women, like all of us, should continue to take precautions to reduce their chances of exposure to the virus. This includes continuing social distancing, hand-washing and mask-wearing."

Should I get vaccinated?

All pregnant women should be offered the COVID-19 vaccine as part of the UK roll out. They will be offered the vaccine at the same time as the rest of the population, based on their age and clinical risk group.

Kate Marsh, Tommy’s Midwifery Manager said:

“There is no known risk with the COVID-19 vaccine during pregnancy or while breastfeeding and we know that the COVID-19 vaccines do not contain live coronavirus and cannot infect a pregnant woman or her unborn baby in the womb. It is completely understandable to be concerned about getting a vaccine during pregnancy, but you don’t have to make this decision alone. We would encourage all pregnant women to talk to their GP or midwife about the vaccination so they can make an individual decision about how to protect themselves.”

Find out more about the Covid-19 vaccine in pregnancy and breastfeeding.

Find out more about coronavirus and pregnancy.