Twenty pregnant or postpartum women have needed intensive care treatment for Covid-19 since the end of June, according to a leading obstetrician.
The vast majority of these women were unvaccinated, according to the chair of the Institute of Obstetricians and Gynecologists.
Dr Cliona Murphy, who also works at the Coombe Maternity Hospital, described the number as "striking".
Speaking on RTÉ's News at One she said this weekend alone had seen three women from maternity hospitals in Dublin city moved to general hospitals for ventilation and ICU care.
"That has given us a bit of shock," she said.
From November 2020 up until June of this year, 22 women who were pregnant or had very recently given birth needed ICU care "so to have 20 in four months is significant".
Dr Murphy also said obstetrics might see one seriously ill mother a year in need of ECMO - a specialised life support unit which is only available in one hospital here.
"This year there has been quite a handful who needed this kind of treatment which she described as extraordinary.
Mothers who are moved to ICU care for Covid treatment can be there for up to five weeks.
She said the HSE would be developing pop-up vaccine clinics at maternity hospitals this week, which would be open to all women of any gestation, and their partners.
Earlier this month, the Health Service Executive's Chief Clinical Officer said that they have seen a "disproportionate" number of pregnant women entering ICU.
Dr Colm Henry said that they would like to see more pregnant women come forward for vaccination.
This morning, the head of the HSE's Covid-19 vaccination programme said that there has been an increase in the number of people in the general population coming forward for a vaccine in recent days.
Speaking on RTÉ's Morning Ireland, Damien McCallion said that since last Thursday the number of people coming forward has increased from 800-1,000 per day to around 2,000 a day.
Mr McCallion said the HSE has been working with hospitals to try and make a certain amount of vaccines available in most major hospitals, including maternity services.
He said the idea is to make it more readily accessible for someone who is in for an appointment, or for others who come into hospital and have not had a vaccine.