COVID-19 vaccines don’t cause miscarriages or stillbirths contrary to misleading interpretations of VAERS data

COVID-19 vaccines increase the risk of miscarriages and stillbirths
Factually Inaccurate: The claim is contradicted by many scientific studies showing that COVID-19 vaccines aren’t associated with any increase in negative pregnancy outcomes.
Scientific studies showed that COVID-19 vaccines don’t cause miscarriage or stillbirths. Pharmacosurveillance monitoring databases such as VAERS cannot be used alone to establish a causal association between vaccination and any medical condition. Public health agencies and medical associations recommend pregnant women to get vaccinated against COVID-19.

FULL CLAIM: COVID-19 vaccines increase the risk of miscarriages and stillbirths


Vaccine misinformation founded on misleading presentations of data from adverse event databases are still going strong on social media. One example of this is a graph posted by Instagram users in March 2023, depicting a sharp increase in miscarriages and stillbirths reported to the U.S. Vaccine Adverse Events Reporting System (VAERS).

Included in the post is the hashtag #FauciForPrison, referencing the former director of the U.S. National Institute of Allergy and Infectious Diseases (NIAID) and chief medical advisor to the U.S. President during the COVID-19 pandemic.Together, these elements implied that COVID-19 vaccines were to blame for the uptick in miscarriages and stillbirths reports.

However, such claims are inaccurate and contradicted by scientific evidence, misusing VAERS data in a way that promotes vaccine misinformation. This review explains why.

Scientific data indicates that COVID-19 vaccines are safe for pregnant women

The initial clinical trials undertaken for the COVID-19 vaccines’ authorization excluded pregnant women due to ethical and legal concerns[1]. This is common practice for new drugs and vaccines but does lead to a lack of data on that population. However, this information gap has since been filled by later studies and there is now a wealth of data showing that pregnancy outcomes are similar between vaccinated and unvaccinated women.

In a retrospective study on more than 85,000 births in Canada, researchers found that COVID-19 vaccination didn’t increase the risks of negative pregnancy outcomes such as stillbirths, preterm birth or small for gestational age at birth[2].

Another study on women who gave birth between March 2020 and July 2021 in England found no differences in the risk of stillbirths and other perinatal safety outcomes, such as fetal abnormalities or small for gestational age[3].

Another study analyzed the risk of miscarriage or ectopic pregnancy of vaccinated women compared to unvaccinated women and to pre-pandemic historical data. They found that the COVID-19 vaccination wasn’t associated with any increased risks of miscarriage and ectopic pregnancy[4]. A study from Switzerland comparing the rate of pregnancy negative-outcome in vaccinated women to pre-pandemic historical data reached similar conclusions[5].

Other studies took the reverse approach. Instead of comparing how many women had a miscarriage between the vaccinated and unvaccinated categories, they compared how many women were recently vaccinated between the “miscarriage” and the “ongoing pregnancy” categories. Consistent with all the results above, they didn’t find any overrepresentation of vaccinated women in the category who suffered a miscarriage. In other words, there was no association between vaccination and miscarriage[6,7].

Systematic reviews of the available scientific literature on the topic also found that COVID-19 vaccination didn’t raise the risks for miscarriages or stillbirths[8,9].

Not only COVID-19 wasn’t associated with a risk of pregnancy loss, but it didn’t increase the risk for other pregnancy negative outcomes either. Indeed, studies from the U.S. and Israel found that vaccinated and unvaccinated women had equal risks of outcomes like preterm births or small for gestational age[10,11].

In conclusion, all these studies consistently showed that COVID-19 vaccines don’t cause miscarriages or stillbirths.

Pharmacosurveillance databases like VAERS alone cannot establish that a vaccine caused the adverse event

Using VAERS data showing an increase of miscarriages in 2021 and 2022 to imply that COVID-19 vaccines are dangerous is misleading and is a misuse of the database. VAERS provides the general public and healthcare workers with an avenue to report adverse events occurring in people after they were vaccinated. The system is co-managed by the U.S. Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA). It serves as “a national early warning system to detect possible safety problems in U.S.-licensed vaccines”, which “can provide CDC and FDA with valuable information that additional work and evaluation is necessary to further assess a possible safety concern.”

However, the database alone cannot be used to suggest that a vaccine is dangerous, as Health Feedback explained in previous reviews. First, because anyone can submit a report to VAERS, the information in the report isn’t verified. VAERS clearly warns users relying on the database about this caveat: “Some reports may contain information that is incomplete, inaccurate, coincidental, or unverifiable. Most reports to VAERS are voluntary, which means they are subject to biases”.

Second, VAERS data alone can’t show whether an adverse event is the consequence of vaccination. Indeed, the sole fact that event A occurs before event B doesn’t mean that the first one caused the second. Suggesting otherwise is known as the post hoc ergo propter hoc fallacy. Further investigation into VAERS reports are required in order to determine whether there is a causal association.

Lastly, the number of adverse events such as deaths or miscarriages reported into VAERS is influenced by people’s propensity to file such reports. The intense media attention on COVID-19 vaccines and their safety has likely produced a greater level of public awareness, which plausibly also led to more reports being submitted, as biostatistician Jeffrey Morris told Therefore, the larger number of reports being submitted for the COVID-19 vaccines compared to previous vaccines isn’t necessarily a sign of a more dangerous vaccine.



Published on: 30 Mar 2023 | Editor:

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