Pregnant women are being urged to have the coronavirus vaccine to "protect themselves and their unborn baby" after new data showed more than 99% of pregnant women admitted to hospital with Covid-19 are unvaccinated.
Health chiefs also said the risk of preterm birth is two to three times higher in women with Covid symptoms.
Pregnant women with existing underlying medical conditions are at a higher risk of becoming seriously unwell with coronavirus if they become infected.
Leading up to 22 July, figures show that around 1,677 pregnant women in Wales have had their coronavirus vaccine - although this figure is likely to be an underestimate.
Public Health Wales is now encouraging pregnant women to have the Covid vaccine to "protect themselves and their unborn baby".
The women will be offered the Pfizer or Moderna vaccine.
Dr Richard Roberts, head of the Vaccine Preventable Disease Programme (VPDP) at Public Health Wales, said the risk to pregnant women is "generally low" but they are also more likely to need intensive care if they contract Covid-19.
“All pregnant women are encouraged to have their Covid-19 vaccine when invited, to protect themselves and their unborn baby.
"The risk to pregnant women and newborn babies from Covid-19 is generally low. However the risk of preterm birth is two to three times higher in women with Covid symptoms, and pregnant women are also more likely to need intensive care, and severe and fatal cases do occur.
"Pregnant women with existing underlying medical conditions are at higher risk of becoming seriously unwell with COVID-19 if they become infected."
Dr Roberts said pregnant women and women who are breast-feeding are already routinely and safely offered vaccines in pregnancy - for example to protect against influenza and whooping cough.
He added, "Many of these vaccines also protect their babies from infection. These vaccines, like the Covid-19 vaccines, are non-‘live’ vaccines, which are considered by experts to be safe in pregnancy and when breast feeding.
"If a pregnant woman has already started [Covid] vaccination she should have her second dose with the same vaccine. You can receive the vaccine in all stages of pregnancy and women planning a pregnancy do not need to delay their vaccination or pregnancy
“It is your choice whether to have the vaccine. Make sure you know as much as you can about the vaccine and risks of Covid-19 in pregnancy to help you make an informed decision.
"The Royal College of Obstetricians and Gynaecologists (RCOG) have developed a useful information decision aid that can be found on the Public Health Wales website. You can also talk to your midwife, doctor or the vaccinator at the clinic."