New Study Links Early Pregnancy mRNA COVID Vaccines to Higher Miscarriage Rates

November 19, 2025

A new preprint study analyzing mRNA COVID-19 vaccines administered during early pregnancy is intensifying scrutiny of federal vaccine policy and increasing pressure on Health and Human Services Secretary Robert F. Kennedy Jr. to take regulatory action.

The study, authored in part by top advisers to President Trump’s former FDA and CDC teams, found a statistically significant increase in fetal loss rates among women who received mRNA COVID-19 vaccines during the first trimester.

The study, not yet peer-reviewed, examined more than 226,000 pregnancies recorded by Maccabi Healthcare Services in Israel. Researchers compared fetal loss rates from pregnancies in the three years before and after COVID-19 emerged.

Our new pre-print on COVID-19 vaccine safety in pregnancy is out!

Women vaccinated in early pregnancy (weeks 8-13) had a higher-than-expected number of fetal losses:

Dose 1 = 3.9 more per 100 women
Dose 3 = 1.9 more per 100 women

Based on data on >200K pregnancies in Israel
🧵 pic.twitter.com/oCKiuvXuhC
— Josh Guetzkow (@joshg99) June 20, 2025

Among pregnant women who received an mRNA vaccine between weeks 8–13, the fetal loss rate rose from 9 per 100 pregnancies to 13—a 43% increase.

A similar trend was observed in booster recipients during the same gestational window, with two additional losses per 100 pregnancies reported.

2/
Late pregnancy losses were a *big* part of the signal.

Among all women:

1.1% lost their pregnancy after week 24.

Compared to:

2.7% of women who received dose 1 in early weeks.

1.8% of women who received dose 3 in early weeks. pic.twitter.com/dEZ1PSvLAK
— Josh Guetzkow (@joshg99) June 20, 2025

The research team included Tracy Beth Hoeg, senior FDA adviser for clinical sciences and former Florida Public Health Integrity Committee member; MIT professor and ACIP member Retsef Levi; and ER physician Joseph Fraiman, who has previously raised concerns about mRNA vaccine safety.

The study’s lead author, sociologist Josh Guetzkow of Hebrew University, has also contributed to previous COVID-19 vaccine safety literature.

The study’s authors say the elevated miscarriage risk appears unique to COVID-19 vaccines.

Pregnant women who received seasonal flu vaccines during the same gestational periods, as well as those who received vaccines prior to pregnancy, experienced no such increase.

The research controlled for common biases using comparison groups to isolate the effect of COVID vaccination.

“Pregnant women were excluded from the pivotal randomized clinical trials used for the initial regulatory approvals of the COVID-19 vaccines,” the authors noted.

Only one randomized controlled trial was conducted by Pfizer, involving 173 women vaccinated in later stages of pregnancy.

The findings come amid mounting criticism of Secretary Kennedy’s approach to mRNA vaccine oversight. Kennedy, a longtime vaccine skeptic, has walked a middle line during his tenure, removing some CDC guidance for healthy pregnant women but stopping short of banning mRNA-based products.

He also disbanded the CDC’s Advisory Committee on Immunization Practices citing conflict of interest concerns, but his agency has approved some new mRNA-based therapeutics.

A growing group of critics is demanding stronger action.

Americans for Health Freedom, led by Texas physician Dr. Mary Talley Bowden, issued an open letter titled “Not for Sale,” urging Kennedy to remove all mRNA vaccines from the market.

The letter claims the data shows “catastrophic levels of deaths and serious damage … including high miscarriage rates.”

The letter also warns Kennedy and FDA Commissioner Marty Makary of political consequences, stating, “You will pay a political price … for the midterms and even for 2028,” if mRNA vaccines are not pulled from public circulation.

Among the original signatories were Naomi Wolf and Henry Ealy, both of whom have led efforts to challenge COVID-era health data transparency and safety oversight.

[twitter-code url="https://twitter.com/MdBreathe/status/1937166790187999660"]

Critics have also cited Pfizer’s own post-market surveillance data, released after court-ordered disclosures, which found a 44% pregnancy loss rate among women in early-stage clinical trials.

Pfizer did not respond to requests for comment on the Israeli study or the prior trial data.

Meanwhile, legal efforts by the Informed Consent Action Network (ICAN) to obtain FDA records on vaccine safety are facing resistance from HHS and the Justice Department.

ICAN attorney Aaron Siri recently said the department is seeking an 18-month delay in the release of documents relating to myocarditis data in teens and internal guidance used to develop vaccine policy.

The CDC’s adult COVID-19 vaccine uptake has hovered around 20% for two consecutive seasons, according to the National Immunization Survey.

Whether new data will shift public opinion or policy remains uncertain.

HHS has not publicly responded to the findings of the Israeli study or the renewed calls for action by vaccine safety critics.

The issue is expected to remain central as regulatory and political debates continue over the future of mRNA therapeutics in the United States.

RED VOICE MEDIA

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