Tdap, Vaccine During Pregnancy: Frequently Asked Questions from Pregnant Women Receiving Care at University Medical Center Ho Chi Minh City

The Tdap vaccine (which protects against three diseases: tetanus, diphtheria, and pertussis) plays an essential role in protecting both mother and baby from serious diseases, particularly pertussis and neonatal tetanus. This article from University Medical Center Ho Chi Minh City addresses the most common questions mothers have about Tdap vaccination during pregnancy, based on the latest medical recommendations available in 2025.

1. What Is the Tdap Vaccine and Why Should Pregnant Women Get Vaccinated?

What Diseases Does the Tdap Vaccine Protect Against?

Tdap is a combination vaccine that protects against three serious infectious diseases: tetanus, diphtheria, and pertussis [2].

• Tetanus: Causes painful muscle stiffness and may lead to an inability to open the mouth, difficulty swallowing, difficulty breathing, or death [2].
• Diphtheria: May cause difficulty breathing, heart failure, paralysis, or death [2].
• Pertussis: Also known as whooping cough, it causes severe, uncontrollable coughing that can make breathing and eating difficult. Pertussis can be particularly serious in infants and young children [2].

How Dangerous Is Pertussis for Newborns?

Pertussis is most dangerous for newborns, particularly during the first few months of life [3]. Most pertussis-related deaths in infants occur in babies who are too young to be fully protected by routine childhood pertussis vaccination, which typically begins at 2 months of age [3]. During this period, infants are at the highest risk of developing pertussis and experiencing serious, life-threatening complications such as pneumonia, seizures, brain damage, or death [2], [3].

What Benefits Does Tdap Vaccination During Pregnancy Provide for the Baby?

Tdap vaccination during pregnancy provides important protection for both mother and baby [3], [4]:

• Protects the mother: Helps prevent the mother from contracting pertussis and transmitting the infection to her newborn [3].
• Provides passive antibodies to the baby: When the mother receives Tdap, her body produces antibodies. These antibodies cross the placenta to the fetus, providing passive immunity during the first few months of life—the period when the baby is most vulnerable to pertussis [3], [4].
• Prevents hospitalization and death: Studies have shown that Tdap vaccination during pregnancy prevents 78% of pertussis cases in infants younger than 2 months and is up to 91% effective in preventing cases requiring hospitalization [3].

2. When Should Pregnant Women Receive the Tdap Vaccine?

What Is the Best Time to Receive Tdap During Pregnancy?

Whether this is a woman’s first pregnancy or a subsequent pregnancy, she should receive one dose of Tdap during every pregnancy, regardless of whether she has received Tdap previously [1], [3]. The optimal timing for Tdap vaccination is between 27 and 36 weeks of pregnancy, preferably at the beginning of this period, as vaccination during this window helps maximize maternal antibody levels and the transfer of passive antibodies to the fetus [1], [3].

If I Have Received Tdap Before, Do I Need to Receive It Again During Pregnancy?

Yes. Tdap should be administered during every pregnancy, even if you received Tdap previously as a young adult or during a previous pregnancy [1], [4]. The purpose is to ensure that the highest possible level of antibodies is transferred to each baby, providing optimal protection during infancy [3].

Can I Receive Tdap at the Same Time as Other Vaccines?

Tdap can be administered at the same time as other vaccines recommended during pregnancy, such as influenza, RSV, or tetanus vaccines.

3. Is Tdap Vaccination Safe for Mother and Baby?

What Are the Common Side Effects After Vaccination?

Most side effects of Tdap vaccination, including when administered during pregnancy, are mild to moderate and resolve on their own [3]. Common side effects include [2]:

• Pain, redness, or swelling at the injection site.
• Mild fever, headache, or fatigue.
• Nausea, vomiting, diarrhea, or abdominal pain.

Serious adverse reactions are extremely rare [2], [3].

Does the Tdap Vaccine Affect the Fetus?

Both Tdap vaccines, Boostrix® and Adacel®, have been approved by the U.S. Food and Drug Administration (FDA) and the World Health Organization (WHO) for use during pregnancy. The Ministry of Health of Vietnam has licensed two vaccines for pregnant women and closely monitors vaccine safety through the Vaccine Adverse Event Reporting System. To date, no concerning safety signals have been identified in pregnant women or their babies following Tdap vaccination.

Who Should Not Receive the Tdap Vaccine?

You should inform your vaccination provider if you have ever experienced [3]:

• A severe allergic reaction after a previous dose of a tetanus-, diphtheria-, or pertussis-containing vaccine.
• Coma, decreased consciousness, or prolonged seizures within 7 days after a previous pertussis-containing vaccine.
• A history of seizures or other nervous system problems.
• A history of Guillain-Barré syndrome (GBS).
• Severe pain or swelling following a previous tetanus- or diphtheria-containing vaccine.

In some cases, a healthcare provider may decide to defer Tdap vaccination [2]. People with mild illnesses, such as a common cold, can generally still receive the vaccine. However, those with moderate or severe illness are usually advised to wait until they recover [2].

4. Frequently Asked Questions About Tdap Vaccination During Pregnancy (FAQ)

• I have received Tdap before. Do I need to receive it again during pregnancy?
  Yes. The CDC recommends one dose of Tdap during every pregnancy, regardless of how long ago you received Tdap. This helps ensure the highest possible level of antibodies is transferred to the baby [1], [3].
• What happens if I do not receive Tdap during pregnancy?
  If Tdap is not administered during pregnancy, the baby will not receive maternal antibodies that provide protection against pertussis during the first months of life, potentially increasing the risk of severe disease or death [3].
• Does the Tdap vaccine affect the fetus?
  No. Safety studies of Tdap have found no evidence of harm to the fetus. The vaccine is approved by the FDA, and the CDC recommends its safe use during pregnancy [3], [4].
• During which trimester should I receive Tdap?
  The optimal timing is between 27 and 36 weeks of pregnancy, preferably at the beginning of this period. However, the vaccine may be administered at any time during pregnancy when indicated [1], [3].
• Can I receive Tdap at the same time as other vaccines?
  Yes. Tdap can be administered at the same time as other vaccines without affecting their effectiveness or safety [2].
• Does Tdap protect against tetanus and diphtheria?
  Yes. Tdap is a combination vaccine that protects against tetanus, diphtheria, and pertussis [2].
• Who should receive Tdap in addition to pregnant women to protect the newborn?
  All individuals who have close contact with the newborn, including fathers, grandparents, and caregivers, should also receive Tdap to create a protective “cocoon” around the baby. However, vaccination during pregnancy is particularly important because it directly provides antibodies to the baby [3].

5. Editorial Review Information & References

Medical Consultation

• MSc. MD Nguyen Hien Minh – Deputy Head of the Vaccination Unit, Department of Medical Examination, University Medical Center Ho Chi Minh City.

References

• [1] Centers for Disease Control and Prevention (CDC). Guidelines for Vaccinating Pregnant Women. https://www.cdc.gov/vaccines-pregnancy/hcp/vaccination-guidelines/index.html. Accessed November 15, 2025.
• [2] World Health Organization. Pertussis Vaccines: WHO Position Paper. Wkly Epidemiol Rec. 2015;90(35):433–4.
• [3] Centers for Disease Control and Prevention (CDC). Vaccinating Pregnant Patients | Whooping Cough. https://www.cdc.gov/pertussis/hcp/vaccine-recommendations/vaccinating-pregnant-patients.html. Accessed November 15, 2025.
• [4] Centers for Disease Control and Prevention (CDC). Pregnancy and Vaccines. https://www.cdc.gov/vaccine-safety/about/pregnancy.html. Accessed November 15, 2025.

The information provided above is for reference purposes only and does not constitute medical advice or a recommendation. Please contact your physician for detailed consultation.