Fact Check-There is still no evidence that COVID-19 vaccines increase risk of miscarriage 

A popular blogpost says there has been a 2000% increase in the number of miscarriages in the United Kingdom “due to” expectant mothers receiving a COVID-19 vaccine. However, the country’s medicines regulator told Reuters there is still no evidence of this, having already debunked a similar claim in March by the same writers.

The headline of the article, published on May 16 by The Daily Expose, reads: “Number of women to lose their unborn child after having the Covid Vaccine increases by 2000% in just fourteen weeks”. It says the authors are “both saddened and shocked” by the number of miscarriages “as a result” of the vaccines (

Referring to data compiled by the Medicines and Healthcare products Regulatory Agency (MHRA) ‘Yellow Card’ scheme (here), which is used to report suspected adverse drug reactions (ADRs), the article makes several calculations.

It says four women suffered a miscarriage “as a result of” the Pfizer/BioNTech shot from Dec. 9 (when the vaccination campaign began) to Jan. 24. This figure increases to 66 between Jan. 24 and May 5 – a rise of 62, or 1700%, the writers say.

Similarly, for the Oxford/AstraZeneca vaccine, the article says two women suffered miscarriages between Dec. 9 and Jan. 24. This increases to 52 by May 5 – a rise of 50, or 2500%, the writers say.

However, this logic is misleading – and has previously been addressed by Reuters when the same writers said in March that there had been a 366% rise in miscarriages in six weeks (here).

Firstly, neither article acknowledges that reports to the Yellow Card scheme are not definitive links to any vaccine. “Many suspected ADRs reported on a Yellow Card do not have any relation to the vaccine or medicine and it is often coincidental that they both occurred around the same time,” an MHRA representative told Reuters via email.

There is also no consideration given to the expected frequency of miscarriages. The representative added: “Sadly, miscarriage is estimated to occur in about 1 in 4 pregnancies.” Most of these occur in the first trimester, or 12 weeks of pregnancy, so “some miscarriages would be expected to occur following vaccination purely by chance.” (here)

The MHRA  did, however, say it had received a “small number” of reports of first trimester miscarriages, which it is “closely monitoring”.

Finally, both articles fail to mention the overall number of COVID-19 vaccines administered. Experts told Reuters in March that the number of miscarriages reported must be compared to the frequency of vaccination, rather than analysing the former without additional context.

For example, more than 6.5 million people had received their first dose of a vaccine by Jan. 24, increasing to 22.3 million by March 7. Nearly 35 million people had received their first shot by May 5 (here).

The Joint Committee on Vaccination and Immunisation (JCVI) updated its guidance in April to encourage pregnant women in the United Kingdom to get the Pfizer/BioNTech or Moderna vaccines. "There is no evidence to suggest that other vaccines are unsafe for pregnant women, but more research is needed," it said. (here) 

Reuters also spoke to several vaccine manufacturers about the claims – and both AstraZeneca and Pfizer said there was currently no clinical evidence of a causal link between their respective COVID-19 vaccines and miscarriage.

An AstraZeneca spokesperson added: “Pre-clinical studies do not indicate direct or indirect harmful effects with respect to pregnancy or foetal development, however these studies are ongoing.”

Representatives from Moderna did not respond to a request for comment from Reuters by the time of publication.

Conversely, a study published in the British Medical Journal (BMJ) in March found that pregnant women are at a higher risk of suffering from severe COVID-19. (here)


Missing context. Yellow Card reporting is not proof of a definitive link to vaccine. The article also does not take into account expected frequency of miscarriages in the population.

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