What is pertussis?

Pertussis is an infection of the lungs and respiratory tract caused by the bacterium Bordetella pertussis. It presents as a "violent cough" or "whooping cough" and is highly contagious. You can become infected by inhaling droplets when someone with pertussis coughs or sneezes. Some factors that increase the likelihood of getting pertussis include pregnancy, lack of immunisation, epidemic exposure, and close contact with infected individuals.¹

After getting infected, you may feel typical flu-like symptoms, such as fever, runny nose, fatigue, and sometimes red eyes. This phase is when the disease is most contagious. After that, a whooping phase follows, characterised by repeated coughing spells and a forceful inhalation creating a distinctive "whoop" sound. Coughing often worsens at night and may lead to difficulty breathing or cyanosis (blueness of the skin). The final phase is a residual cough that can last weeks to months, usually triggered by irritants or other respiratory infections.^1,2

Why is pertussis a concern in pregnancy?

Pregnancy has been identified as one of the risk factors for illness and complications from respiratory tract infections, such as influenza. The reason for this is that during pregnancy, there are physiological changes such as decreased lung capacity, increased oxygen consumption, as well as changes in your immune system. Flu in pregnancy also increases the risk of complications, including pregnancy loss and preterm labour. However, specifically for pertussis, there is not enough evidence suggesting that if you are pregnant and get infected by whooping cough, it will harm the baby.³

However, this disease is highly infectious and serious in young babies, especially those under 6 months old. The symptoms can be very severe and life-threatening. That is why pregnant women must be vaccinated against whooping cough to protect their babies by passing the antibody during pregnancy. Some of the possible complications that may happen if a baby suffers from pertussis are pneumonia, bleeding (haemorrhage), pulmonary hypertension, hernia, sore ribs even fractures, urinary incontinence, and respiratory failure.^4,5

How can pregnant women protect their babies?

If you're expecting, your midwives will recommend getting a whooping cough vaccine between 16 and 32 weeks of pregnancy. You can receive the vaccine any time after 16 weeks, but its effectiveness may decrease if administered after 32 weeks. It's crucial to note that during each pregnancy, vaccination is advised, regardless of prior immunisation. If you missed the vaccine during pregnancy, you can still get it within the first two months after giving birth. This vaccination will indirectly protect your baby and reduce the risk of transmitting the infection to them. However, this is less ideal than having the vaccine in the recommended schedule.^6,7

The safety of pertussis vaccine during pregnancy

Maternal immunisation is crucial to give protection for the baby towards various diseases. A study shows that a pertussis vaccination successfully achieves high pertussis antibody concentration in infants and is 64-93% effective in preventing the disease among babies under two months old. In cases where the infant gets the disease, it will be less severe than in a baby whose mother did not get vaccinated.⁸

Despite this fact, some mothers still have doubts, worries, and hesitations about getting the vaccine for safety reasons, and it is very understandable if you feel this way. However, there is no evidence indicating that getting the pertussis vaccine during pregnancy is unsafe, either for you or for your baby. Research shows that maternal immunisation does not adversely affect pregnancy, birth, or neonatal outcomes. There is also no evidence showing increased rates of systemic or local reactions for pregnant women receiving the vaccine, nor an increased risk of adverse events related to pregnancy, including stillbirth. Knowing that the benefits of reducing potential harm to the baby outweigh the risks, vaccination is recommended.^8,9

Vaccination procedure

Between 16-32 weeks of pregnancy, your midwives will offer you whooping cough vaccination. After giving consent for the vaccination, you will receive the vaccine at your GP or antenatal clinic. Similar to other vaccinations, it will be injected into your upper arm. You will be informed about potential reactions you may experience after the injection, such as redness, swelling, or tenderness at the injection site. It's normal to feel soreness in your arm, which should only last a few days. Other possible side effects include a high temperature, headache, fatigue, and loss of appetite.

The type of vaccine that is usually given is BOOSTRIX-IPV, which is a combination of diphtheria, tetanus, acellular pertussis (dTpa), and inactivated poliovirus vaccine. This is similar to the 4-in-1 vaccine given as a preschool booster to children. So, in one vaccine shot, you will give protection against these four diseases to your baby.¹⁰

What happens after the baby is born?

Pertussis vaccination during pregnancy is meant to protect your baby, especially in the first two months of life. They will receive the whooping cough vaccine at 8 weeks through the 6-in-1 vaccine. If you become pregnant again, you should be revaccinated starting from 16 weeks in each pregnancy to ensure continued protection for your baby.¹⁰

FAQs

How does pertussis affect pregnancy?

Pertussis during pregnancy is generally not dangerous for the mother, though it can be uncomfortable. However, if the mother does not receive the pertussis vaccination during pregnancy, it poses a significant risk to the baby. Newborns, particularly those under 6 months old, are vulnerable to pertussis infection, which can lead to severe and life-threatening conditions such as pneumonia and respiratory failure. Vaccination is essential to transfer antibodies to the baby, providing crucial protection against the disease before they can receive their vaccinations.

Can excessive coughing during pregnancy harm the baby?

Rest assured, coughing itself is not harmful to your baby. However, it can be uncomfortable for you, especially if it persists. Symptoms such as chest tightness, fatigue, and sleep disturbances may occur. Pregnancy increases your risk of getting sick and acquiring infections due to a weakened immune system. It also makes you more vulnerable to irritants and seasonal changes. Additionally, the pressure from the uterus on the abdomen may lead to acid reflux.

Although generally safe, if your cough becomes severe and persistent, it's advisable to contact your midwives. They can offer assistance and ensure no underlying risks or conditions are posing a threat to you or your baby.

Can the whooping cough vaccine cause early labour?

No, it doesn’t. Getting a pertussis vaccine won’t increase your risk of preterm labour or other complications, such as low birth weight.

Who is at the highest risk for pertussis?

Most cases of pertussis are diagnosed in infants below one year of age and adolescents between 10 and 20 years old. Additionally, certain groups are at increased risk of pertussis:¹¹

• Individuals with underlying diseases such as asthma, chronic obstructive pulmonary disease (COPD), or obesity
• Those with immunodeficiency
• Smokers
• People who are not vaccinated

What months is pertussis most common?

Pertussis infection can happen at any time of the year. However, most cases are diagnosed during the summer and fall. 

Summary

Pertussis is a highly contagious infection affecting the respiratory system and caused by Bordetella pertussis. This infection, also known as whooping cough, is characterised by high-pitched "whoop" sounds produced when inhaling. During pregnancy, if you become infected by pertussis, there is no major concern for you as a mother. However, the main concern lies in the danger to the newborn if they contract pertussis. Newborns are still vulnerable as their immune systems are still developing. Pertussis in infants is known to be dangerous and life-threatening, with various complications such as pneumonia, breathing difficulties, bleeding, hernia, pulmonary hypertension, and more.

A pertussis vaccination for the mother during pregnancy is recommended to protect the baby when they are born, especially during the first two months of life. The vaccination is typically administered between 16 and 32 weeks of pregnancy to provide the best protection. By passing antibodies to the baby, it is hoped that they will not suffer from the infection when they are born. If you are concerned about the safety of this vaccination, don’t worry. There is no evidence showing adverse effects on you, your pregnancy, or the baby.