COVID‐19 Vaccination During Pregnancy and Birth Defects - a US 2021-2022 study

[Red Phoenix]

Source: https://pmc.ncbi.nlm.nih.gov/articles/PMC12093198/

 

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And here the results and conclusions of that study: 

Results

Participants reported receiving Pfizer‐BioNTech vaccines (59.0%), Moderna (38.2%), and Janssen (2.8%) vaccines. Most (65.2%) participants received their first COVID‐19 vaccine after the first trimester. The prevalence of major birth defects was 3.8%. Among defects with comparator estimates available (n = 50), 35 were below or within expected ranges. C19VPR prevalences were higher than the comparator confidence interval for 15 defects; however, C19VPR confidence intervals included comparator estimates. Prevalences did not differ by the timing of vaccination for seven defects examined.

Conclusions

Birth defects prevalence estimates among infants born to women receiving COVID‐19 vaccines during or just prior to pregnancy were generally similar to pre‐pandemic estimates. While there was no strong evidence of associations between vaccination and specific defects, statistical power was low.

 

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> So the study concludes that there is 'nothing to see here'.

That is until you delve into the study... 

The study reports a 3.8% prevalence of major birth defects among infants born to women vaccinated during or just prior to pregnancy, concluding this rate is consistent with pre-pandemic U.S. estimates and finds no strong evidence of increased risk. However, a critical examination reveals several methodological and interpretative limitations that challenge these conclusions.

To be addressed in my follow-up post in this thread...

 

[Red Phoenix]

When I came across this study, I smelled a rat...

The study wants us to believe that 3.8% prevalence of major birth defects is 'normal', while I know that the actual (and widely accepted) figure is 3% (with a confidence interval of 2.8 to 3.2%). 

 

So I queried ChatGPT about this.  

And in first instance the program came with several plausible explanations for the 3.8% (a 27% increase over 3.0%).  

Then I pointed out to the program that the study did not give a confidence interval for its 3.8% claim as normal, but that they had only looked at the increases of specific birth defects.  All of these did fall within the confidence limits, but they did not mention the accumulation of these individual defects, because when doing that there is a clear signal that on the whole birth defects have increased.  And the program did confirm that that was a methodological error by the study authors (I would say that it was a deliberate omission as it undermines their conclusion).  

 

Furthermore I pointed to 2 red flags I came across when reading the study: 

#1 - The study states that: The overall prevalence of participant‐reported major birth defects in the C19VPR (3.8%) was similar to estimates published prior to the COVID‐19 pandemic and COVID‐19 vaccine availability (3%–5%) (Centers for Disease Control and Prevention 2008; Texas Department of State Health Services 2024).

#2 - The study also states that: Our analysis is based on birth defects identified up to 4 months after birth, while existing birth defect surveillance systems in the United States typically include birth defects identified through at least 1 year after birth. Thus, we may have underestimated the prevalence of some birth defects.

 

So by cherry-picking those specific limited population reports the study compares their 3.8% prevalence to a wide 3%–5% range, and by doing so the authors reduce the ability to argue that their observed rate is truly elevated. 

Secondly, they admit that the 'completely normal' 3.8% they come up with is actually underestimated because they only looked at the period of 4 months after birth, while in US typically this is followed up till at least 1 year after birth. 

 

 If an interested amateur like me can easily see these shortcomings that totally undermine the study's 'nothing to see here' conclusion, the small CYA note at the end of the study does not come as a surprise to me:

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

 

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[Red Phoenix]

We are talking about a 27% increase in birth defects during the 2021-2022 period of Covid-19 vaccination roll-out.  

And let's not forget that each and every birth defect is a human tragedy.  

[TallGuyJohninBKK]

I smell a rat too, mostly in your continuing assault of misleading, nonsense posts:

 

Newborn and Early Infant Outcomes Following Maternal COVID-19 Vaccination During Pregnancy

October 23, 2023

 

Findings  In this population-based cohort study of 142 006 live births in Ontario, Canada, maternal mRNA COVID-19 vaccination during pregnancy was associated with lower risks of severe neonatal morbidity, neonatal death, and neonatal intensive care unit admission and no increase in neonatal readmission or hospital admission up to age 6 months, compared with no maternal COVID-19 vaccination before delivery.

 

Meaning  Maternal mRNA COVID-19 vaccination during pregnancy was not associated with increased adverse newborn and early infant outcomes and may be protective against adverse newborn outcomes. [emphasis added]

 

https://jamanetwork.com/journals/jamapediatrics/fullarticle/2810937

 

 

 

[TallGuyJohninBKK]

Covid vaccines for pregnancy and babies: Sorting fact from chaos

Jun 04, 2025

...

"the American College of Obstetricians and Gynecologists (ACOG) and other medical organizations strongly recommend vaccination during pregnancy, and they continue to do so.

 

Since then, multiple “real-world” studies (i.e., not tightly controlled clinical trials) across different populations have confirmed: the vaccine is safe and effective for pregnant women. We’ve seen this over and over again:

• A 2024 meta-analysis of 1.8 million pregnant vaccinees found no increased risk of bad outcomes for the pregnant person, fetus, or infant, and found that vaccination with any COVID-19 vaccine reduced the risk of hospitalization by 94%.

• A 2021 study in the New England Journal of Medicine following 35,000 vaccinated pregnant individuals found no increase in adverse pregnancy or neonatal outcomes." [emphasis added]

 

https://yourlocalepidemiologist.substack.com/p/covid-vaccines-for-pregnancy-and

 

YLE is a public health newsletter that reaches over 380,000 people in more than 132 countries, with one goal: to translate the ever-evolving public health science so that people are well-equipped to make evidence-based decisions.

 

[TallGuyJohninBKK]

No increase in birth defects found following COVID vaccination in pregnancy

July 20, 2024

 

"A new study adds to the growing body of literature demonstrating the safety of COVID-19 vaccine use in pregnant women. The study, published in BMJ, showed no connection between COVID vaccination or infection in the first trimester of pregnancy and congenital birth defects. 

 

The study is based on outcomes seen among 343,066 live-born single infants in Sweden, Denmark, and Norway with an estimated first trimester of pregnancy occurring from March 1, 2020, to February 14, 2022. The infants were followed up for at least 9 months after birth. 

...

"We add to the current evidence with our results showing that there appears to be no robust evidence of an increased risk of any of the subgroups of congenital anomalies," the authors concluded. "Overall, our findings support the current recommendations to vaccinate pregnant women against COVID-19."

 

https://www.cidrap.umn.edu/covid-19/no-increase-birth-defects-found-following-covid-vaccination-pregnancy

 

 

 

[TallGuyJohninBKK]

COVID-19 vaccination during pregnancy not linked to birth defects

April 08, 2025

...

COVID-19 vaccination during pregnancy was not associated with major structural birth defects, according to a study published in Pediatrics.

 

Researchers found no difference in the prevalence of birth defects between people who were and were not vaccinated. They also did not find a difference in safety outcomes between the two manufacturers of COVID-19 messenger RNA vaccines, Moderna and Pfizer-BioNTech.

 

“The catch phrase ‘nothing to see here’ is good when it comes to vaccine safety research,” Stacey L. Rowe, PhD, MPH, an infectious disease epidemiologist at Monash University in Melbourne, Australia, told Healio. “Studies from Israel, Scotland, Scandinavia and the U.S. have similarly found no link between COVID-19 vaccination during pregnancy and birth defects. Thus, our findings are consistent with previously published research.” [emphasis added]

 

Healio

https://www.healio.com/news/pediatrics/20250408/covid19-vaccination-during-pregnancy-not-linked-to-birth-defects