A small cough in an adult can look harmless. In a newborn, that same infection can turn serious very quickly. That is why pertussis vaccine pregnancy comes up so often during antenatal visits: whooping cough (pertussis) spreads fast, and babies are at their most vulnerable before their first routine vaccinations.

You may be thinking, “My baby will get vaccines anyway—why should I take one now?” Or, “Will it affect my pregnancy?” Let’s make it simple and practical: what pertussis is, how it spreads in Indian households, how antibodies pass from mother to baby, the usual timing for Tdap, safety, side effects, and what to do if the ideal window is missed.

What pertussis (whooping cough) is and how it spreads

Pertussis is a respiratory infection caused by Bordetella pertussis, a bacterium that sticks to the airway lining and releases toxins that irritate and inflame the breathing tubes. The result? A cough that can be relentless.

It spreads through droplets when an infected person coughs, sneezes, laughs, or speaks at close distance—think shared bedrooms, crowded lifts, school pick-ups, family gatherings, clinic waiting areas.

The tricky bit is the beginning. It often starts like a simple cold (runny nose, mild cough). That early phase is also when people are highly contagious, sometimes even before anyone says, “This does not look like a regular cough.”

In family life, the source is commonly an adolescent or adult with a lingering cough—an older sibling, a parent, a grandparent, a domestic helper, or a visitor. They may feel “mostly fine” and still pass it on. Even brief exposure can be enough.

Why newborns are most at risk before their first DTaP dose

Newborns have narrow airways, limited energy reserves, and they get exhausted quickly. Their own primary vaccine series for pertussis (as part of DTP/DTaP depending on the country schedule) usually starts around 6 weeks to 2 months. That leaves a gap right at the start.

Without antibodies transferred from the mother during pregnancy, a very young baby can become unwell fast. And pertussis in infants may not show the classic “whoop.” Instead, parents may notice:

• Long, frequent coughing bouts (paroxysms)
• Difficulty feeding (tiring quickly, poor intake)
• Vomiting after coughing
• Pauses in breathing (apnoea)
• Bluish lips/face or low oxygen episodes, sometimes leading to hospital admission

If your baby is under 3 months and has repeated coughing fits, poor feeding, or any breathing pause, do not wait it out—call your paediatrician or go to emergency care.

Pregnancy: a unique chance to pass protection to your baby

Pregnancy changes immunity in a very specific way. The mother’s immune system adjusts to support the pregnancy while still producing antibodies against infections.

Here is the practical advantage behind pertussis vaccine pregnancy: after Tdap vaccination, the mother makes IgG antibodies against pertussis antigens. These IgG antibodies cross the placenta (this is called transplacental antibody transfer) and reach the baby before birth—especially in late pregnancy.

So the baby is born with ready antibodies. This is passive immunity: the newborn is not yet producing strong defences, but can benefit from the mother’s antibody head start.

Breast milk also contains immune factors (including antibodies). Breastfeeding supports the baby after birth, but it does not replace the placenta-to-baby transfer achieved with pertussis vaccine pregnancy.

Pertussis symptoms: how it looks in babies and adults

Pertussis typically progresses in phases:

• Early (catarrhal) phase (often 1–2 weeks): cold-like symptoms and mild cough, this is when it spreads easily
• Paroxysmal cough phase: repeated coughing fits that can trigger vomiting and exhaustion, symptoms may continue for weeks

In infants, complications can be severe:

• Pneumonia (a common reason for hospitalisation)
• Apnoea and low oxygen episodes
• Dehydration and poor weight gain due to feeding difficulty
• Seizures or encephalopathy (rare, but serious)

In adults and older children, pertussis often appears as a prolonged, intense cough. Complications are usually less severe but can include pneumonia, fainting, urinary leakage, and rib injury from violent coughing. Adults remain a major source of infection for babies—one more reason pertussis vaccine pregnancy matters.

Why getting Tdap during pregnancy helps your newborn

Main benefit: protection in the first weeks of life

The aim is straightforward: reduce the baby’s risk of pertussis from day one.

Real-world studies show that Tdap given during pregnancy is associated with large reductions in pertussis in very young infants, especially under 2–3 months—before the first infant doses can fully protect.

Added family benefit: reducing illness and household spread

Tdap also lowers the mother’s chance of catching pertussis during late pregnancy and early postpartum, a period full of close face-to-face contact (feeding, soothing, skin-to-skin, night wakings). If the mother is protected, the household risk often drops too.

How vaccination in pregnancy protects the baby

After Tdap, the immune system produces IgG antibodies. These cross the placenta and can be detected in the baby’s blood at birth.

A key timing point: after a Tdap dose, it takes roughly about two weeks for antibody levels to rise substantially. That is why planning pertussis vaccine pregnancy within the recommended window is so useful.

Protection is strongest in the early newborn period and then naturally fades over the first months. This is expected—maternal antibodies are meant to be a bridge until the infant’s own vaccine series takes over.

Understanding the vaccines: Tdap vs DTaP/DTP vs Td

The abbreviations can feel confusing, so here is a clean breakdown:

• Tdap: tetanus + diphtheria + acellular pertussis booster for adolescents/adults, used for pertussis vaccine pregnancy
• DTaP/DTP: higher-antigen formulations used for infants and young children as a multi-dose primary series (naming varies by country)
• Td: tetanus + diphtheria only (no pertussis component)

Tdap is a non-live vaccine. It cannot cause pertussis.

You may see different labels across countries (Tdap, dTpa, dTcaP). The principle is the same: protection against tetanus, diphtheria, and acellular pertussis (purified antigens, not whole bacteria). Some products include polio as well.

Timing recommendations: when is pertussis vaccine pregnancy given?

One dose in every pregnancy

Many programmes advise one Tdap dose in each pregnancy, even if you took it in a previous pregnancy. Antibody levels drop over time, and each baby benefits from a fresh, well-timed antibody boost.

Timing windows vary

Commonly used windows include 27–36 weeks, and in some places 20–36 weeks. The goal stays the same:

• early enough for the mother to mount an antibody response
• close enough to delivery for efficient placental transfer

Vaccinating earlier within the late-pregnancy window can help if there is a chance of preterm delivery.

If Tdap is given earlier in the same pregnancy (for example, after a wound), guidance that follows “one dose per pregnancy” often does not advise repeating it later. Your obstetrician can confirm what applies in your setting.

How effective Tdap in pregnancy is for infants

Effectiveness estimates vary by study design and local disease rates, but protection in early infancy is consistently strong.

• Studies often report roughly 69% to 93% effectiveness against lab-confirmed pertussis in early infancy.
• Some evaluations report around a 78% reduction in pertussis cases in infants under 2 months after third-trimester maternal vaccination.

Protection against severe outcomes is especially high in multiple studies:

• around 91% to 94% effectiveness against pertussis-related hospitalisation in very young infants
• about 95% effectiveness against pertussis-related death in the first months of life

What can influence protection?

• the exact timing of pertussis vaccine pregnancy
• vaccine coverage locally
• how much pertussis is circulating
• exposure patterns (school-going siblings, frequent visitors, crowded indoor contact)

Safety of Tdap during pregnancy

Large studies and ongoing vaccine safety monitoring support Tdap use in pregnancy. Surveillance has not identified signals suggesting harm to pregnant women or their babies due to Tdap.

Tdap is non-live and uses purified pertussis components. Formulations differ by brand (for example, adjuvants and trace ingredients), so if you have a history of allergy or prior vaccine reactions, share it with your clinician.

Side effects: what is common, what needs urgent attention

Most people experience no symptoms or mild, short-lived effects:

• Pain, redness, or swelling at the injection site
• Tiredness, headache, mild body aches
• Low-grade fever

These usually settle within 1–3 days.

What can help?

• Move the arm gently, use a cool compress
• Rest and fluids
• If required, ask your antenatal team which pain reliever is suitable in pregnancy for you

Urgent care is needed if there are signs of a severe allergic reaction (hives, swelling of lips/face, breathing difficulty, dizziness), a high fever with worsening symptoms, or if you feel severely unwell.

Who needs extra medical advice before vaccination

Tdap is usually avoided if you have had:

• a life-threatening allergic reaction to a previous dose or known component
• encephalopathy within 7 days after a pertussis-containing vaccine, without another identifiable cause

Discuss timing carefully with your clinician if:

• you have a moderate/severe acute illness (vaccination may be postponed)
• you had Guillain–Barré syndrome after a tetanus-toxoid–containing vaccine
• you experienced an Arthus-type severe local reaction after tetanus/diphtheria vaccines

Also mention latex allergy, if any, as packaging can differ.

If Tdap happens after birth: postpartum vaccination and its limits

Postpartum Tdap can still help protect the mother and reduce household spread. But it does not provide immediate newborn immunity, because:

• the main transfer of protective IgG happens through the placenta during pregnancy
• it takes about two weeks after vaccination for the mother to build higher antibody levels

If pertussis vaccine pregnancy was missed, clinicians often strengthen postpartum vaccination, focus on limiting exposure, and ensure the baby starts their routine vaccines on time.

Cocooning: vaccinating the people around the baby

Cocooning means vaccinating close contacts so they are less likely to bring pertussis home. It is helpful, but difficult to implement perfectly—especially in large families or when visitors come and go.

So, cocooning works best as an extra layer, not as a substitute for pertussis vaccine pregnancy.

Consider Tdap updates for:

• the baby’s other parent
• grandparents and frequent visitors
• caregivers, including babysitters
• siblings as per the age-based schedule

Ideally, give these vaccines at least two weeks before close contact with the newborn.

Coordinating Tdap with flu and COVID-19 vaccines

Different vaccines have different aims:

• pertussis vaccine pregnancy focuses on newborn protection in the first weeks
• influenza and COVID-19 vaccines primarily reduce the pregnant mother’s risk of severe illness (with indirect benefits for the baby)

Tdap can be taken at the same visit as the flu shot (separate syringes, often different arms). COVID-19 vaccines can also be given during pregnancy, including with Tdap.

If you prefer spacing injections, plan it so Tdap still falls in the recommended window.

If pregnancy is advanced or the vaccine window was missed

If you are still in the recommended window used where you live, Tdap can still be beneficial.

If delivery is very close, the time for antibody transfer is limited. In that case, the plan often shifts to:

• postpartum Tdap for the mother
• strong cocooning for close contacts
• careful hygiene and visitor management
• keeping the baby’s immunisation schedule on track

Practical steps while waiting for the baby’s first doses:

• Avoid visits from anyone who is sick or coughing
• Wash hands before holding the baby
• Keep rooms well-ventilated
• Avoid tobacco smoke exposure
• Take persistent cough in close contacts seriously (medical review may be needed)

Getting vaccinated in real life: practical steps in India

Depending on your city and provider, Tdap may be offered:

• at an obstetrician’s clinic during an antenatal visit
• through a hospital antenatal clinic
• via a family physician
• at some pharmacies or vaccination centres (as per local rules)

Carry your pregnancy file and any immunisation record you have. Ask for documentation of the vaccine name/brand, date, and batch/lot number.

If you are unsure how to bring it up, simple lines work well:

• “I want to plan Tdap in this pregnancy. What week do you prefer?”
• “If it is not available here, where can I take it, and can you note it in my antenatal record?”

After birth: the baby still needs their own DTP/DTaP doses

Maternal antibodies fade over time. That is normal.

So even after pertussis vaccine pregnancy, your baby must start their routine immunisations on schedule (often around 6 weeks/2 months, then further doses as advised). Those doses train the baby’s immune system to build longer-term protection.

Sometimes a parent hears about blunting: maternal antibodies can slightly reduce how strongly the baby’s antibody levels rise right after their own vaccines. In day-to-day practice, this effect is small and has not been shown to cancel the benefit of maternal vaccination. The early protection gained at birth—when risk is highest—remains the big advantage.

To remember

• Pertussis spreads easily and can be dangerous for newborns, sometimes causing apnoea and hospitalisation.
• Pertussis vaccine pregnancy helps protect the baby from birth through placental transfer of maternal IgG antibodies.
• Many settings advise one Tdap dose in every pregnancy, timing often falls in late pregnancy (commonly 27–36 weeks, sometimes 20–36).
• Protection is strong in early infancy, especially against severe outcomes.
• Side effects are usually mild and short-lived, serious reactions are rare.
• Postpartum Tdap helps protect the mother but does not give immediate newborn immunity.
• Cocooning helps, but it does not replace pertussis vaccine pregnancy.
• The baby still needs routine DTP/DTaP doses on time.

For extra support and personalised guidance, you can download the Heloa app for personalised advice and free child health questionnaires, and keep your obstetrician and paediatrician involved in decision-making.

Further reading :

• Whooping cough vaccination in pregnancy (https://www.nhs.uk/pregnancy/keeping-well/whooping-cough-vaccination/)
• Vaccinating Pregnant Patients | Whooping Cough (https://www.cdc.gov/pertussis/hcp/vaccine-recommendations/vaccinating-pregnant-patients.html)
• Vaccination in Pregnancy against Pertussis – PubMed Central (https://pmc.ncbi.nlm.nih.gov/articles/PMC9786323/)