At Summit Women’s & Wellness Medical Group in Rancho Cucamonga, CA, Dr. Renee Obey emphasizes the importance of preventive healthcare during pregnancy, including timely vaccinations. Among these, the flu vaccine is one of the most essential tools for protecting both maternal and infant health. Influenza, commonly known as the flu, is a serious respiratory illness that can have significant complications for pregnant women. Due to changes in the immune system, heart, and lungs during pregnancy, women are more vulnerable to severe illness from the flu. Fortunately, the flu vaccine offers safe and effective protection that not only shields the mother but also provides immunity to the unborn child. In this blog, we’ll explore the relationship between pregnancy and the flu vaccine, addressing safety, benefits, timing, and common concerns.
Understanding the Risks of Influenza in Pregnancy
Pregnancy significantly alters a woman’s immune system, making her more susceptible to infections, including influenza. When a pregnant woman contracts the flu, her symptoms can be more severe than those experienced by non-pregnant individuals. This is due in part to the increased strain on the heart and lungs, as well as hormonal changes that affect immune response.
Influenza during pregnancy increases the risk of serious complications such as pneumonia, bronchitis, sinus infections, and ear infections. In more severe cases, the flu can lead to hospitalization, respiratory failure, and even death. According to the Centers for Disease Control and Prevention (CDC), pregnant women are more likely to be hospitalized from the flu than women of reproductive age who are not pregnant.
The flu also poses risks to the fetus. High fevers caused by influenza during the first trimester have been linked to neural tube defects and other developmental issues. Additionally, contracting the flu later in pregnancy increases the likelihood of preterm labor, low birth weight, and stillbirth. These risks underscore the importance of flu prevention through vaccination.
The Safety of the Flu Vaccine in Pregnancy
A common concern among pregnant women is whether vaccines are safe for them and their unborn babies. The flu vaccine, when administered as the inactivated injectable form (not the nasal spray), has been extensively studied and proven to be safe during all trimesters of pregnancy. It does not contain live virus, which means it cannot cause the flu.
Decades of research and monitoring have consistently shown no increased risk of pregnancy complications, miscarriage, or birth defects associated with the inactivated flu vaccine. In fact, numerous health organizations, including the CDC, the American College of Obstetricians and Gynecologists (ACOG), and the World Health Organization (WHO), recommend that all pregnant individuals receive the flu shot.
The vaccine not only protects the mother but also passes antibodies through the placenta to the fetus, offering the baby protection during the first few months of life—when they are too young to receive the flu vaccine themselves. This early immunity is especially valuable during flu season, when newborns are most at risk for complications.
Timing the Flu Vaccine During Pregnancy
The best time to receive the flu vaccine is before flu season begins, ideally by the end of October. However, getting vaccinated later in the season can still offer protection and is strongly encouraged. The flu season typically peaks between December and February but can last as late as May.
Pregnant women can receive the inactivated flu vaccine at any point during pregnancy—whether they are in their first, second, or third trimester. The important thing is to ensure timely vaccination to minimize the risk of flu exposure, particularly during the later months of pregnancy when flu-related complications are more likely to occur.
Because it takes about two weeks after vaccination for the body to develop sufficient antibodies, early vaccination offers the best chance of staying protected throughout the season. Women who are planning to become pregnant during flu season should also consider receiving the vaccine before conception to establish early immunity.
The Benefits of Maternal Immunity for Newborns
One of the most compelling reasons to receive the flu vaccine during pregnancy is the protection it offers the newborn. Infants under six months of age are at a high risk for serious flu complications but are not eligible for the flu vaccine. This leaves them vulnerable during a critical developmental window.
When a pregnant woman receives the flu vaccine, she produces antibodies that cross the placenta and are transferred to the fetus. These antibodies provide passive immunity that can last for several months after birth, effectively shielding the baby from the flu until they are old enough to be vaccinated themselves.
Research has shown that maternal vaccination reduces the risk of influenza infection in infants by up to 63% during the first six months of life. This early protection can reduce hospitalizations, lessen the severity of illness if the baby does contract the flu, and support overall infant health during a time of rapid development and immune system maturation.
Addressing Common Concerns and Myths
Despite the strong medical consensus on the benefits of flu vaccination during pregnancy, many women still have questions or hesitations. Some fear that the vaccine could harm their baby or cause them to become ill, while others believe they are unlikely to catch the flu or that their symptoms would be mild if they did.
It’s important to clarify that the flu shot cannot cause the flu, as it contains an inactivated (killed) virus. Mild side effects such as soreness at the injection site or low-grade fever may occur but are short-lived and far less serious than the flu itself. These symptoms are signs that the body is building immunity.
Additionally, even healthy individuals can catch the flu, and pregnancy amplifies the risks of complications. Relying solely on handwashing, healthy eating, or avoiding crowds is not enough to ensure protection, particularly during peak flu season. Vaccination remains the most reliable and effective form of defense for both mother and child.
Concerns about vaccine ingredients, allergic reactions, or interactions with other medications should be discussed with a healthcare provider. Most pregnant women tolerate the vaccine well, and serious side effects are extremely rare.
Complementary Ways to Stay Healthy During Flu Season
While the flu vaccine is the most effective tool for flu prevention during pregnancy, it should be part of a broader strategy to stay healthy. Pregnant women can further reduce their risk of illness by incorporating a few practical habits into their daily routine.
Frequent handwashing with soap and water is essential, especially after being in public places, touching shared surfaces, or caring for sick individuals. Avoiding close contact with people who are ill and refraining from touching the face—particularly the eyes, nose, and mouth—can help prevent the spread of germs.
Maintaining good nutrition, staying well-hydrated, and getting adequate sleep support a healthy immune system. Regular prenatal care also ensures that any signs of illness can be identified and treated early. If flu-like symptoms do arise, pregnant women should seek medical advice promptly, as early treatment with antiviral medications can reduce the risk of complications.
Final Thoughts
Pregnancy is a time of anticipation, growth, and care—not only for the baby but also for the mother. The flu vaccine is a simple, safe, and effective way to protect both during a vulnerable period. It reduces the likelihood of serious illness, prevents complications, and provides critical immunity to newborns during their earliest months. At Summit Women’s & Wellness Medical Group in Rancho Cucamonga, CA, Dr. Renee Obey encourages all pregnant women to prioritize their health through informed, proactive choices like timely flu vaccination. A healthier pregnancy begins with protection—for both you and your baby.
Resources
- Grohskopf, L. A., et al. (2023). Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices. MMWR Recommendations and Reports.
- Zaman, K., et al. (2008). Effectiveness of Maternal Influenza Immunization in Mothers and Infants. New England Journal of Medicine.
- Rasmussen, S. A., et al. (2012). Pandemic Influenza and Pregnant Women: Summary of a Meeting of Experts. American Journal of Public Health.