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Influenza and Pregnancy

Flu vaccination in pregnancy protects you and your newborn.

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Key Summary

  • 3-for-1 protection: Vaccination protects the parent during pregnancy, the baby before birth (via placenta), and the newborn through breast milk.
  • Risks of flu in pregnancy: People are more vulnerable during pregnancy to severe illness and complications like pneumonia, heart inflammation, premature birth, low birth weight, and stillbirth.
  • Risks for babies: Infants under 6 months (too young for their own flu shot) have the highest hospitalisation rates for influenza.
  • Vaccine benefits:
    • Safe at any stage of pregnancy.
    • Free under the National Immunisation Program.
    • Reduces stillbirth risk by ~20% and lowers flu-related hospitalisation for parents and babies.
    • Cuts flu risk in infants under 6 months by ~50%.
  • Other precautions: Handwashing, avoiding sick contacts, and vaccinating household members further reduce risk.
  • Safety record: Millions of people worldwide have been safely vaccinated during pregnancy with no evidence of harmful birth outcomes.

About

Getting vaccinated against influenza during pregnancy offers a 3-for-1 benefit:

  • It protects the parent during pregnancy and in the early months of parenthood
  • It protects the unborn baby through the transfer of antibodies across the placenta
  • It protects the newborn through antibodies in breast milk

The influenza vaccine is safe, effective, and free during pregnancy in Australia.

How serious is influenza during pregnancy?

Pregnancy naturally suppresses the immune system, making people more vulnerable to infections like influenza. Changes in the heart and lungs also make it more difficult to fight off illness. This means influenza can be more severe during pregnancy, leading to complications such as:

  • Pneumonia
  • Heart inflammation
  • Premature birth
  • Stillbirth
  • Low birth weight

Babies under six months—who are too young to be vaccinated—are also at high risk of hospitalisation and complications like pneumonia. In fact, this age group consistently shows the highest hospitalisation rates from influenza compared to any other age group in Australia.¹

During the 2009 H1N1 influenza pandemic in Australia, pregnancy was associated with a high risk of ICU admission, with more than half of surviving patients delivering preterm.²

How can you reduce the risk of catching influenza while pregnant?

1. Get Vaccinated

Influenza vaccination is the most effective way to protect both parent and baby. Vaccination during pregnancy reduces the risk of:

  • Hospitalisation from influenza
  • Severe complications like pneumonia and cardiac illness
  • Stillbirth by approximately 20%3

The influenza vaccine is:

  • Free during pregnancy under the National Immunisation Program
  • Safe to receive at any stage of pregnancy

2. Practice Good Hygiene

Alongside vaccination:

  • Wash hands regularly
  • Avoid close contact with sick people
  • Cover your mouth and nose when coughing or sneezing

These basic precautions can help reduce your chance of catching or spreading influenza.

When should you get vaccinated?

The influenza vaccine can be given at any stage of pregnancy. It is best given before the influenza season starts (typically April–June in Australia), but it can be given at any time of year and still provide meaningful protection to both the parent and the baby.

Will the baby be protected?

By getting vaccinated, you pass on protective antibodies through the placenta to your baby which will protect your infant in the first six months of life.

Studies have found that maternal influenza vaccination can reduce the risk of influenza in infants aged under 6 months by about 50%, and is also associated with a 20% reduction in the risk of stillbirth3,4.

Babies cannot be vaccinated against influenza until they are six months of age so they rely on maternal vaccination for protection in the first six months of life.

Vaccinating household contacts who will be in close contact with the baby will also help to reduce the transmission of the virus to the baby.

How safe is the influenza vaccine during pregnancy?

Flu vaccinations have been given to millions of pregnant women over the years with an excellent safety record.

Many large studies have shown no evidence of harmful birth outcomes like birth abnormalities, stillbirth or low birth weight5-8.

Injection site reactions and fever do not occur more frequently in pregnant than non-pregnant women.

References

  1. Bratton KN, Wardle MT, Orenstein WA, Omer SB. Maternal influenza immunization and birth outcomes: a systematic review and meta-analysis of observational studies. Am J Obstet Gynecol. 2015;213(6):697–708.e1. doi:10.1016/j.ajog.2015.05.023
  2. Australian Technical Advisory Group on Immunisation (ATAGI). Influenza (flu): Infants and children [Internet]. Canberra: Australian Government Department of Health and Aged Care; 2024 [cited 2025 May 8]. Available from: https://immunisationhandbook.health.gov.au/contents/vaccine-preventable-diseases/influenza-flu#infants-and-children
  3. Knight M, Pierce M, Seppelt I, et al. Critical Illness with AH1N1v Influenza in Pregnancy: A Comparison of Two Population-based Cohorts. BJOG. 2011;118(2)232-9
  4. Regan AK, Moore HC, de Klerk N, Omer SB, Shellam G, Effler PV. Influenza vaccine during pregnancy and the incidence of stillbirth: population-based retrospective cohort study. Clin Infect Dis. 2016;62(10):1221–1227.
  5. Knight M, Pierce M, Seppelt I, et al. Critical illness with AH1N1v influenza in pregnancy: a comparison of two population-based cohorts. BJOG. 2011;118(2):232–239
  6. Kharbanda EO, Vazquez-Benitez G, Romitti PA, Naleway AL, Cheetham TC, Lipkind HS, et al. First trimester influenza vaccination and risks for major structural birth defects in offspring. JAMA Pediatr. 2017;171(3):239–47. doi:10.1001/jamapediatrics.2016.4081
  7. McMillan M, Porritt K, Kralik D, Costi L, Marshall H. Influenza vaccination during pregnancy: a systematic review of fetal death, spontaneous abortion, and congenital malformation safety outcomes. Vaccine. 2015;33(18):2108–17. doi:10.1016/j.vaccine.2015.02.068
  8. Zaman K, Roy E, Arifeen SE, Rahman M, Raqib R, Wilson E, et al. Effectiveness of maternal influenza immunization in mothers and infants. N Engl J Med. 2008;359(15):1555–64. doi:10.1056/NEJMoa0708630