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Tom Kertscher
By Tom Kertscher May 18, 2023

Do Tdap shots expose pregnant women to undue risk? No. Studies show the vaccines are safe

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  • Researchers have studied thousands of pregnant women who got the Tdap vaccine, which aims to prevent tetanus, diphtheria and pertussis, aka whooping cough.

  • The vaccine is recommended for pregnant women by the federal Centers for Disease Control and Prevention and the American College of Obstetricians and Gynecologists.

An Instagram post suggested that expectant mothers who get vaccinated against tetanus, diphtheria and pertussis, also known as whooping cough, are volunteering their bodies for a risky trial.

"Still wondering why a certain three-letter agency recommends pregnant women get the Tdap shot when the manufacturer even states there are no controlled studies of pregnant women using this, and they can’t get ethics approval to experiment on pregnant women," the post said. "So, pregnant women getting it voluntarily are quite literally the experiment." 

The post was flagged as part of Meta’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Meta, which owns Facebook and Instagram.)

Researchers have done clinical trials with thousands of pregnant women who have received the Tdap, said Dr. C. Buddy Creech, director of Vanderbilt Vaccine Research Program at Vanderbilt University Medical Center in Tennessee.

"We give vaccines to people once they have been thoroughly evaluated for safety and efficacy; administering Tdap in pregnancy is no exception," he said.

The federal Centers for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists recommend the Tdap vaccination during pregnancy.

Tdap is a combined vaccine given to adolescents and adults to prevent three bacterial diseases: tetanus, diphtheria and pertussis. (Another vaccine known as DTaP, for diphtheria, tetanus and acellular pertussis, is given to children.)

Diphtheria can lead to breathing problems, paralysis and heart failure. Tetanus causes painful tightening of the body’s muscles and can lead to "locking" of the jaw, preventing people from opening their mouths or swallowing. Diphtheria and tetanus can be fatal. 

Pertussis can be serious, particularly in infants, perhaps leading to pneumonia, seizures or brain damage. 

The federal Food and Drug Administration in 2005 approved two Tdap vaccines, Boostrix and Adacel for people, including pregnant women. To prevent infant pertussis, the FDA in 2022 approved Boostrix during pregnancy and, in 2023, approved Adacel.

Research on pregnant women has found the Tdap vaccine to be safe and effective. 

  • A December 2022 medical journal article listed six randomized controlled trials on pregnant women. The article said infants whose mothers received the Tdap had "significantly higher" antibodies to prevent pertussis.  

  • A 2015 study published in the Journal of the American Medical Association included more than 29,000 pregnant women in six states. It found no birth defects for the children of women vaccinated with Tdap during pregnancy. A 2014 JAMA study looked at more than 26,000 pregnant women in California and reached the same conclusion.

  • New Zealand researchers in 2016 observed 793 pregnant women for four weeks after the Tdap vaccination and found no "serious adverse events likely to be caused by the vaccine."

  • A 2020 controlled study of 687 pregnant women found the Tdap was safe and provided infants more pertussis antibodies.

The CDC said that safety monitoring by it and the FDA has found the Tdap vaccine safe for pregnant women and their babies. Administering the vaccine during pregnancy does not increase risk for pregnancy complications such as low birth weight or preterm delivery, the CDC said.

Tdap is recommended during pregnancy in more than 50 countries, said Dr. Elyse Kharbanda, executive research director, HealthPartners Institute in Minnesota.

"Studies from our group and others have consistently demonstrated the safety of Tdap vaccine when administered in pregnancy," she said.

We rate the Instagram post False.

Our Sources

Instagram, post (archived), May 13, 2023

Journal of Tropical Medicine, "Safety and Immunogenicity of Pertussis Vaccine Immunization during Pregnancy: A Meta-Analysis of Randomized Clinical Trials," Dec. 21, 2022

Human Vaccines and Therapeutics journal, "Randomized clinical trial of the safety and immunogenicity of the Tdap vaccine in pregnant Mexican women," 2017

AAP Factcheck, "No link between Gates, vaccines and microcephaly in Brazil," March 29, 2021

PolitiFact, "DTaP vaccine is safe and effective, contrary to social media claims," Oct. 24, 2022

PolitiFact, "Canadian website wrongly links whooping cough vaccine to Zika," Feb. 16, 2016 

American College of Obstetricians and Gynecologists, "The Tdap Vaccine and Pregnancy," April 2022

Vaccine journal, "Immunogenicity, transplacental transfer of pertussis antibodies and safety following pertussis immunization during pregnancy: Evidence from a randomized, placebo-controlled trial," Feb. 18, 2020

Centers for Disease Control and Prevention, "Diphtheria, Tetanus, and Pertussis Vaccines," March 6, 2023

Centers for Disease Control and Prevention, "Vaccine Safety," Dec. 1, 2022

Clinical Infectious Diseases journal, "A Randomized Controlled Trial of the Safety and Immunogenicity of Tetanus, Diphtheria, and Acellular Pertussis Vaccine Immunization During Pregnancy and Subsequent Infant Immune Response," Sept. 14, 2018

Journal of the American Medical Association Pediatrics, "US Infant Pertussis Incidence Trends Before and After Implementation of the Maternal Tetanus, Diphtheria, and Pertussis Vaccine," Feb. 6, 2023

Journal of the American Medical Association, "Safety and immunogenicity of tetanus diphtheria and acellular pertussis (Tdap) immunization during pregnancy in mothers and infants: a randomized clinical trial," May 7, 2014

Canadian Medical Association Journal, "Tdap vaccination in pregnancy," June 14, 2021

BMJ Open medical journal, "Safety of Tdap vaccine in pregnant women: an observational study," April 18, 2016

Email, Dr. C. Buddy Creech, director of Vanderbilt Vaccine Research Program at Vanderbilt University Medical Center, May 17, 2023

Email, Dr. Elyse Kharbanda, executive director of research, HealthPartners Institute, May 17, 2023

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Do Tdap shots expose pregnant women to undue risk? No. Studies show the vaccines are safe

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