August is National Immunization Awareness Month, and while vaccines are often discussed in the context of infants and children, there is one vaccine that every pregnant woman needs to know about: the Tdap. It protects against three serious diseases, and when given during pregnancy, it does something remarkable. It passes protective antibodies directly to your developing baby, giving them immunity before they are old enough to be vaccinated themselves.
At Tidewater Physicians for Women, prenatal vaccine counseling is a routine part of our obstetrics care in Virginia Beach and Norfolk. Here is a thorough look at what Tdap is, why timing matters, and what you can expect.
What Is Tdap?
Tdap stands for Tetanus, Diphtheria, and Pertussis. It is a combination vaccine that protects against three bacterial infections:
- Tetanus (Lockjaw): A bacterial infection that causes severe, painful muscle spasms. It is rare but life-threatening, typically entering the body through cuts or wounds.
- Diphtheria: A respiratory infection that produces a thick membrane in the throat, potentially causing breathing difficulties and heart problems. Largely eliminated in the U.S. thanks to vaccination.
- Pertussis (Whooping Cough): A highly contagious respiratory illness characterized by violent, uncontrollable coughing fits. In newborns, it can be fatal.
Of the three, pertussis is the most pressing reason to vaccinate during pregnancy. Whooping cough outbreaks still occur regularly in the U.S., and infants are by far the most vulnerable group.
Why Newborns Are at Highest Risk
Pertussis is particularly dangerous in the first months of life. Infants under two months old cannot receive any vaccines, yet they are also the most likely to experience severe complications, including:
- Pneumonia
- Seizures
- Brain damage from lack of oxygen during coughing fits
- Death
Infants with pertussis often do not make the classic whooping sound that older children and adults do. Instead, they may simply stop breathing during a coughing episode, which is what makes the illness so dangerous and so difficult to recognize quickly in newborns. The gap between birth and the first DTaP vaccine at two months is exactly the window that maternal Tdap vaccination helps close.
How Maternal Vaccination Protects Your Baby
When you receive the Tdap vaccine during pregnancy, your immune system produces antibodies against pertussis, tetanus, and diphtheria. Those antibodies cross the placenta and transfer to your baby, giving them passive immunity that lasts through the first weeks and months of life. Think of it as lending your baby your immunity until they are old enough to build their own. Research consistently shows that babies born to mothers vaccinated with Tdap during pregnancy have significantly higher pertussis antibody levels at birth and lower rates of pertussis infection in the critical early months.
When to Get the Tdap Vaccine
The CDC recommends Tdap during every pregnancy, ideally between 27 and 36 weeks gestation. This window is intentional:
- Before 27 weeks, there is more time for antibody levels to wane before birth.
- After 36 weeks, there may not be enough time for antibodies to fully transfer to the baby before delivery.
- The 27 to 36 week window maximizes the concentration of antibodies transferred to your newborn.
Even if you received Tdap before this pregnancy or during a previous pregnancy, you need it again. The recommendation is once per pregnancy, every pregnancy. Antibody levels decline over time, and re-vaccination with each pregnancy is what provides optimal protection for each new baby.
Is Tdap Safe During Pregnancy?
Yes. The Tdap vaccine has been studied extensively in pregnant women and has a strong safety record. It does not contain live bacteria, so it cannot cause the diseases it protects against. The most common side effects are soreness at the injection site, mild fatigue, or a low-grade fever. Every major medical organization, including ACOG, the CDC, and ACIP, recommends Tdap during pregnancy. The risk of leaving a newborn unprotected against whooping cough is far greater than any risk from the vaccine itself.
The Cocooning Strategy: Protecting Your Baby From All Angles
In addition to maternal vaccination, the cocooning strategy recommends that everyone who will be in close contact with your newborn, including partners, grandparents, siblings, and other caregivers, be up to date on Tdap before the baby arrives. Adults who received only the older Td vaccine as teens may never have had the pertussis component at all. Pertussis spreads most commonly from adults who do not realize they are infected, since the illness looks like a persistent cough in adults rather than the dramatic presentation it has in infants.
Other Vaccines to Ask About During Pregnancy
- Influenza vaccine: Recommended at any stage of pregnancy during flu season. Pregnant women are at higher risk for severe flu complications, and the antibodies you build pass to your baby. Ask about flu shot timing at your next prenatal appointment.
- RSV vaccine (Abrysvo): Recommended between 32 and 36 weeks gestation, from September through January, to protect against Respiratory Syncytial Virus, one of the leading causes of infant hospitalization in the first year of life.
- COVID-19 vaccine: Recommended and updated annually. Ask your provider about timing based on your current vaccination history.
What to Expect at Your Prenatal Appointments
Our care team reviews your immunization history at your prenatal visits and flags upcoming vaccine windows so nothing gets missed. Tdap is typically offered at a visit in the third trimester. If you are approaching 27 weeks and have not been asked about it yet, bring it up. Our obstetrics team is committed to making sure every aspect of your prenatal care is as thorough as possible.
Questions About Prenatal Vaccines?
We would rather you ask than wonder. Bring any vaccine questions to your next visit and we will walk you through the evidence and the timing.
To learn more or schedule an appointment, Schedule your prenatal appointment today or call us at 757-461-3890.
