Tdap During Pregnancy: Risks & Benefits

Tdap during pregnancy - risks & benefits

You’re approaching the 3rd trimester of your pregnancy and your doctor has encouraged you to get the Tdap vaccine. Now you’re full of questions, like what are the benefits and risks? Is it safe for your baby? How does the Tdap during pregnancy help protect my baby? Let’s learn more about this common recommendation, and provide you with the info you need to make an informed choice for you and your baby.

Estimated reading time: 8 minutes

What is the Tdap vaccine?

Tdap is a vaccine that offers protection against tetanus, diphtheria, and pertussis. (We discuss each of these below.) After receiving the vaccine, your body produces antibodies, or special, disease-specific proteins, that recognize the illness and help your immune system to fight it off if you’re ever exposed to it again.


Tetanus is caused by a bacterial infection and can produce painful, involuntary muscle contractions. It’s sometimes called “lockjaw” because often the neck and jaw muscles lock, and a person can’t open their mouth and swallow. The tetanus bacteria is found in soil, dust, and manure. It enters the body when the skin has been broken or punctured by contaminated objects (3).


Diphtheria is a bacterial illness that causes swelling of the mucus membranes of the nose and throat. At the same time, the infection produces a membrane of dead cells that can cover the airway and make it difficult to breathe.

The diphtheria toxin may also damage the nerves of the throat and upper respiratory system, affecting the ability to breathe and swallow. If the toxin enters the bloodstream, it may inflame and damage other tissue, such as the heart (1).


Pertussis, also known as whooping cough, is most dangerous for babies. In the early stages, the illness resembles a cold. As pertussis advances for older children, it results in fits of rapid coughing with a high-pitched “whoop” sound, often followed by vomiting.

Babies with pertussis usually don’t cough at all, which can lead to a build up of mucus and pneumonia. In extreme cases, baby can stop breathing, which may result in seizures and brain damage (2).

Is my newborn at risk for getting these illnesses?

It’s very unlikely that your newborn will be exposed to tetanus through a bite or puncture wound, and diphtheria is extremely rare in the United Sates.

Baby is at greater risk for developing pertussis.

Pertussis, on the other hand, is highly contagious and outbreaks occur more frequently. It is the least controlled of all bacterial vaccine-preventable diseases and is considered a common, or endemic disease in the United States (4). According to the CDC:

  • 1,000 infants are hospitalized each year in US due to pertussis
  • 5-15 infants die each year due to pertussis
  • Most of these deaths occur in infants who are too young to be immunized (less than 2 months old)

As a newborn, your baby enters the world with a greater risk of contracting pertussis than any other age group. And as a newborn, he or she is also more likely to have life-threatening complications from pertussis than any other age group.

Still, the relative risk of baby developing pertussis is low.

Yet, while the risk exists and can lead to death, the relative risk of a baby developing pertussis is still low. Among 1,185,927 infants born in a 5-year span in the US, only 1032 pertussis cases were identified. Less than 0.1% (.087%) of infants develop pertussis (4). Please note that the risk may be higher or lower in other countries, and parents should research the data accordingly.

Why is my doctor offering me Tdap during pregnancy?

There are currently no pertussis vaccines available for newborns. And, vaccinating babies at birth would have limited benefits anyway because a newborn’s immune system can’t create antibodies until they are 2 months old. Thus, vaccination at birth wouldn’t offer immediate protection (8).

To help protect baby during the most vulnerable first few months of life, your doctor or midwife may encourage you to receive the Tdap during pregnancy. When you receive the Tdap vaccine, it will act as a booster to increase your body’s immune response to pertussis. In turn, baby will receive protective antibodies through the placenta during pregnancy and also through your breast milk after birth.

What timing is best to get the Tdap during pregnancy?

Only one dose of Tdap is recommended during pregnancy, and the timing does matter. The level of pertussis antibodies decrease over time and the protection is not long-lasting. Passive antibody transfer to the baby will be at its peak if mom is immunized during the early part of weeks 27 through week 36 of the pregnancy.

If you received the Tdap early in your pregnancy for any reason, you do not need to repeat the vaccine later in your pregnancy (6).

Is it safe to get the Tdap during pregnancy?

Tdap is considered safe

The Tdap vaccine is considered safe for mom and baby during pregnancy. The recommendation to immunize with Tdap is supported by both the American College of Obstetricians and Gynecologists and the American College of Nurse-Midwives (5). Fortunately, studies have not found any increase in significant risks (stillborn baby, death of newborn, preterm birth) for moms who immunize with Tdap during pregnancy versus those who do not (9).

Site reactions may occur

Some moms report reactions on their skin, such as redness, swelling, or muscle pain at the site of the injection. These risks are considered minor and short-term.

How effective is the Tdap during pregnancy at giving baby immunity?

Higher antibody levels

According to a 2017 systematic review, evidence suggests that babies whose mother’s vaccinated during pregnancy had significantly higher antibody levels at birth compared to those with no vaccination (9).

But do those increased antibody levels actually protect newborns from pertussis? One study concluded that the effectiveness of vaccinating during the third trimester was 77.7% (7). Other studies show that if baby does contract pertussis, the infection will be less severe (6). However, there is still a lack of robust evidence to verify this claim.

Despite this, and because the risk to mom and baby is low, immunizing mom during pregnancy is generally considered the best available option. The potential benefit outweighs the risk.

Tdap may interfere with infant response to DTaP

Pediatricians administer the DTaP vaccine to babies and children under the age of 7 to provide immunity against diphtheria, tetanus, and pertussis. The first of 5 does is usually given when baby is 2 months old.

Some studies have revealed that babies have a slightly weakened immune response to the first few DTaP vaccinations when mom was immunized with the Tdap during pregnancy (10). The implications of this are still being studied. In response, the CDC suggests the following:

The benefits of vaccinating during pregnancy and protecting a newborn outweigh the potential risk of blunting the infant’s response to the DTaP. Since infants are at greatest risk of severe disease and death from pertussis before 3 months of age – when their immune systems are least developed – any protection that can be provided is critical.

Centers for Disease Control and Prevention, 2017, (6)

Should I get the Tdap during pregnancy?

The decision whether to get the Tdap during pregnancy is one of many decisions that you’ll make as a new parent. Take your time to study to the research and discuss any questions or concerns you have with your doctor or midwife. With this decision as with many others, with study, you can be prepared and empowered to make the best choices for you and your family.

Kopa Birth’s online birthing classes allow you to prepare for a natural hospital birth from the comfort of your own home, 24/7. Enroll today in our free online childbirth class and start preparing for your natural birth!

  1. Mayo Clinic. (2019). Diptheria. Retrieved at t
  2. Centers for Disease Control and Prevention. (2019). Vaccine (Shot) for Whooping Cough (Pertussis). Retrieved at,pneumonia%20(a%20serious%20lung%20infection)
  3. Centers for Disease Control and Prevention. (2019). Tetanus – Causes and Transmission. Retrieved at
  4. Masseria, C., Martin, C. K., Krishnarajah, G., Becker, L. K., Buikema, A., & Tan, T. Q. (2017). Incidence and Burden of Pertussis Among Infants Less Than 1 Year of Age. The Pediatric infectious disease journal36(3), e54–e61.
  5. American College of Nurse-Midwives. (2014). Position Statement: Immunization in Pregnancy and Postpartum. Retrieved at
  6. Centers for Disease Control and Prevention. (2017). Vaccinating Pregnant Patients. Retrieved at
  7. Skoff TH, Blain AE, Watt J, et al. Impact of the US Maternal Tetanus, Diphtheria, and Acellular Pertussis Vaccination Program on Preventing Pertussis in Infants <2 Months of Age: A Case-Control Evaluation. Clin Infect Dis. 2017;65(12):1977-1983. doi:10.1093/cid/cix724
  8. Centers for Disease Control and Prevention. (2017). Pregnancy and Whooping Cough. Retrieved at
  9. Furuta, M., Sin, J., Ng, E., & Wang, K. (2017). Efficacy and safety of pertussis vaccination for pregnant women – a systematic review of randomised controlled trials and observational studies. BMC pregnancy and childbirth17(1), 390.
  10. Hardy-Fairbanks AJ, Pan SJ, Decker MD, et al. Immune responses in infants whose mothers received Tdap vaccine during pregnancy. Pediatr Infect Dis J. 2013;32(11):1257-1260. doi:10.1097/INF.0b013e3182a09b6a

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Meet Katie Griffin

I’m a registered nurse, Lamaze certified childbirth educator, and the mother of 7. I help women realize their dream of a natural, intimate, and empowering hospital birth.

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You’re approaching the 3rd trimester of your pregnancy and your doctor has encouraged you to get the Tdap vaccine. Now you’re full of questions, like what are the benefits and