COVID-19 vaccines are not related to spontaneous abortions – new research

Newly published research supports the fact that COVID-19 vaccines are not linked to spontaneous abortions in pregnant women. This data supports the CDC’s and other health authorities’ recommendations that pregnant women receive the vaccine to protect themselves and their developing fetus.

However, there was little research that supported the actual safety and effectiveness of the vaccines during pregnancy. Pregnant women were excluded from the early clinical trials, although a few may have been enrolled prior to diagnosis of pregnancy.

A new peer-reviewed research letter provides evidence that the COVID-19 vaccines are not linked to spontaneous abortions or miscarriages.

COVID-19 vaccines and spontaneous abortions paper

In a paper published on September 8, 2021, in JAMA, Dr. Elyse O. Kharbanda, MD, MPH, et al. presented data from case-control surveillance of COVID-19 vaccines during pregnancy and spontaneous abortion. The researchers evaluated data from the Vaccine Safety Datalink during seven 4-week surveillance periods from December 15, 2020, through June 28, 2021. They identified 105 ,446 unique pregnancies, of which 13,160 ended with spontaneous abortions, and 92,286 were ongoing pregnancies (see Note 1).

Of the unique pregnancies identified, the following is the breakdown of COVID-19 vaccines given during pregnancy prior to 20 weeks gestation:

  • 7.8% of women received 1 or more doses of the Pfizer vaccine;
  • 6.0% received 1 or more doses of the Moderna vaccine;
  • 0.5% received 1 dose of the JNJ vaccine during pregnancy.

The researchers analyzed the odds of receiving a COVID-19 vaccine in the 28 days prior to spontaneous abortion compared with the odds of receiving a COVID-19 vaccine in the 28 days prior to index dates for ongoing pregnancies. 

COVID-19 vaccines spontaneous abortions

Here are the results:

  • 8.0% of those with ongoing pregnancies received one of the COVID-19 vaccines.
  • 8.6% of those that had spontaneous abortions received one of the COVID-19 vaccines.
  • Spontaneous abortions did not have an increased odds of exposure to a COVID-19 vaccines in the prior 28 days compared with ongoing pregnancies – adjusted odds ratio of 1.02. This means that there was no greater risk of spontaneous abortions after receiving one of the COVID-19 vaccines.
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The authors concluded:

Among women with spontaneous abortions, the odds of COVID-19 vaccine exposure were not increased in the prior 28 days compared with women with ongoing pregnancies.

This adds more data that the COVID-19 vaccines are safe for the pregnant mother and developing fetus. Of course, this study does not discuss the dangers of COVID-19 itself to pregnant women.

For example, pregnant and recently pregnant women are at higher risk of serious illness when compared to non-pregnant people. Severe illness includes illness that requires hospitalization, intensive care, need for a ventilator or special equipment to breathe, or illness that results in death.

Additionally, pregnant women with COVID-19 are at increased risk of preterm birth and might be at increased risk of other adverse pregnancy outcomes, compared to pregnant women without COVID-19.


  1. The Vaccine Safety Datalink allows for a case control study because the database includes medical records for vaccinated and unvaccinated individuals. You can then compare outcomes between the two groups, such as spontaneous abortions after COVID-19 vaccines. The VAERS database not only cannot establish correlation (let alone causation), you cannot do any case-control studies between vaccinated and unvaccinated groups. The VAERS database also cannot establish whether an adverse event incidence is higher or lower than unvaccinated individuals. VAERS is nearly usless except as a potential safety signal that will require further investigation to confirm.


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The Original Skeptical Raptor
Chief Executive Officer at SkepticalRaptor
Lifetime lover of science, especially biomedical research. Spent years in academics, business development, research, and traveling the world shilling for Big Pharma. I love sports, mostly college basketball and football, hockey, and baseball. I enjoy great food and intelligent conversation. And a delicious morning coffee!