Two pregnant women in Hong Kong who had received the BioNTech Covid-19 vaccine have suffered miscarriages, although a link to the jabs has not been established and health authorities are assessing the cases.

In a statement released on Wednesday evening, the Department of Health revealed it had received the first reports of miscarriages following immunisation since the coronavirus vaccination drive kicked off about two months ago.

“Currently, there is no evidence indicating that the two cases were related to vaccination,” the statement said.

In one of the cases, a 32-year-old woman was treated at Queen Mary Hospital on Sunday for vaginal bleeding and lower abdominal pain. She suffered a miscarriage on the same day, with the dead fetus found to be around 23 to 24 weeks old.

The statement also said “the woman could not give a clear account of her pregnancy information”.

She had received a dose of the German-made BioNTech vaccine at St Paul’s Hospital Community Vaccination Centre on Thursday. There was no record of her complaining to feel unwell during observation at the centre. Authorities also did not state if she had indicated to staff that she was pregnant.

The other case involved another 32-year-old woman, who confirmed her pregnancy on March 25, but sought medical treatment at the accident and emergency unit of Queen Elizabeth Hospital on March 31 due to vaginal bleeding. She was found to have had a miscarriage.

She had received a dose of the BioNTech vaccine at Choi Hung Road Badminton Centre Community Vaccination Centre on March 23.

A source said the patient in Queen Mary Hospital was in a stable condition, while the other woman had been discharged.

The two cases came to light after a medical source told media about the incidents. The department said it had received the reports on April 12 and 8, raising questions over the delay in making them public.

The department said it would refer the cases to an expert panel for an investigation.

BioNTech had said its Covid-19 vaccines were not “routinely recommended” during pregnancy, unless a person was considered to be at a very high risk of exposure to and complications arising from the coronavirus.

Sinovac, the mainland Chinese manufacturer of the other vaccine available in Hong Kong, had said its doses should not be given to pregnant women.

William Chui Chun-ming, president of the Society of Hospital Pharmacists, said the public should not jump to conclusions before investigations were completed.

“Pregnant women, who have unstable chronic diseases such as high blood pressure or diabetes, would be more at risk of the severe adverse effects from Covid-19 vaccinations, just like everyone else with those diseases,” he said.

“But under certain circumstances, pregnant women may want to get vaccinated as it has been proven that the protection also extends to the baby.”

The Hong Kong College of Obstetricians and Gynaecologists had previously said it did not recommend “routine Covid-19 vaccination” for pregnant women due to the lack of adequate clinical data on safety for this group.

It added that those who might be at high risk of developing severe complications because of underlying medical conditions should discuss with their obstetricians before taking the jabs.

As of Tuesday, 8.2 per cent of Hong Kong’s 7.5 million residents had received their first jab since the inoculation programme began in late February, while 4 per cent have completed two doses.