Carrie Johnson has told other pregnant women there is nothing to worry about, after getting her second COVID-19 vaccine.
The prime minister’s wife, who is due to give birth to her second child in December, said she got her second jab on Saturday and was “feeling great”.
Mrs Johnson, 33, said she was concerned about having a miscarriage because of the vaccine but said: “The data shows there is no increased risk of miscarriage.”
When she announced she was pregnant in July, Mrs Johnson also revealed she suffered a miscarriage earlier in the year which left her “heartbroken”.
Posting a picture of herself with a COVID-19 vaccine sticker on her private Instagram on Saturday, she added: “Nearly 200,000 pregnant women across the UK and US have received the Pfizer and Moderna vaccines recommended during pregnancy, without safety concerns.
“The Royal College of Midwives has said that expectant mothers are at greater risk of serious illness if they get COVID so being vaccinated really is the best way to keep you and your baby safe.”
Health chiefs in July started a campaign to urge pregnant women to get the vaccine after data from Public Health England found no pregnant women who had both doses had been admitted to hospital with COVID-19.
Mrs Johnson also used Instagram last month to tell of her miscarriage, saying: “Fertility issues can be really hard for many people, particularly when on platforms like Instagram it can look like everything is only ever going well.
“I found it a real comfort to hear from people who had also experienced loss so I hope that in some very small way sharing this might help others too.”
She and Mr Johnson got married in a secret ceremony at Westminster Cathedral at the end of May.
The new baby will be a sibling to Wilf, 15 months, and it will mean Mr Johnson, 57, is the first prime minister to have two babies born while leading the country.