Immunization Awareness Month: Flu Shot Timing During Pregnancy
August is National Immunization Awareness Month — and it arrives at exactly the right time of year for expectant mothers to be thinking about one of the most important preventive steps they can take before fall: the flu shot. At Cary OB/GYN, flu vaccination is something we discuss with nearly every pregnant patient we see during the summer and early fall months. The reason is simple: flu during pregnancy is more dangerous than most people realize, and the vaccine is both safe and highly effective.
If you're currently pregnant — or planning to be — here's everything you need to know about timing, safety, and why this vaccine matters more than you might think.
Why the Flu Is More Dangerous During Pregnancy
Pregnancy creates a unique set of physiological changes that make women more vulnerable to severe illness from influenza. The immune system undergoes significant shifts during pregnancy to accommodate the growing baby, and those shifts come with tradeoffs in terms of how robustly the body can respond to respiratory viruses. At the same time, the heart and lungs are under increased strain as blood volume grows and the uterus expands.
The result is that pregnant women who contract influenza are significantly more likely than non-pregnant adults to experience serious complications — including pneumonia, hospitalization, respiratory failure, and in severe cases, death. Flu during pregnancy is also associated with an elevated risk of preterm labor and delivery, low birth weight, and in some cases, fetal loss. These aren't rare edge cases; they're documented outcomes that underscore why vaccination is so strongly recommended.
The American College of Obstetricians and Gynecologists (ACOG), the Centers for Disease Control and Prevention (CDC), and virtually every major medical organization recommend flu vaccination for all pregnant women.
When Should You Get the Flu Shot?
The flu shot can be given safely at any point during pregnancy — in the first, second, or third trimester. The CDC recommends vaccination as soon as the seasonal flu vaccine becomes available, which is typically in August or September. This timing is important because it gives your immune system approximately two weeks to build protective antibodies before flu season begins to circulate in the fall.
Waiting until flu season is already underway is better than not vaccinating at all — but earlier is better. If you're seen in our office for a prenatal visit in August or September and haven't yet received your flu shot, we'll typically offer it right there. You don't need a separate appointment.
It's also worth noting that the protection you build from the flu shot is passed through the placenta to your baby, who is too young to receive their own flu vaccine until 6 months of age. Vaccinating during pregnancy is one of the few ways to protect a newborn from flu in those critical early months.
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Which Flu Vaccine Is Safe During Pregnancy?
This is a common source of confusion, and it's worth being clear: the inactivated influenza vaccine — commonly called the flu shot — is safe at any stage of pregnancy. It does not contain live virus and cannot cause influenza. The formulation given to pregnant women does not contain thimerosal (a mercury-based preservative) in single-dose vials, though thimerosal-containing multi-dose vials have been studied extensively and are also considered safe.
The live attenuated influenza vaccine — the nasal spray, sometimes called FluMist — is not recommended during pregnancy because it contains a weakened live virus. If you've historically preferred the nasal spray, the shot is the appropriate choice while you're pregnant.
If you have questions or concerns about a specific vaccine formulation, bring them up with your provider. We're happy to walk through the options with you.
What About Flu Shot Side Effects During Pregnancy?
Side effects from the flu shot are generally mild and short-lived. The most common is soreness, redness, or swelling at the injection site. Some people experience low-grade fatigue, mild headache, or a slight fever in the day or two following vaccination — these are signs that the immune system is responding, not signs of illness, and they resolve quickly on their own.
The flu shot does not cause the flu. This is one of the most persistent myths around the vaccine. What some people experience as "getting sick" after the shot is either a coincidental illness, a reaction to the immune response, or — in some cases — an illness contracted before vaccination had time to take effect.
Other Vaccines to Discuss This August
While the flu shot is often the focus of August prenatal vaccine conversations, it's not the only one worth discussing. The Tdap vaccine, which protects against tetanus, diphtheria, and pertussis (whooping cough), is recommended between 27 and 36 weeks of every pregnancy. Like the flu shot, Tdap antibodies cross the placenta and protect your newborn before they're old enough to be vaccinated. Whooping cough in particular can be life-threatening for infants under two months.
An updated COVID-19 booster and, depending on your timing, the RSV maternal vaccine (recommended between 32 and 36 weeks during RSV season) may also be appropriate to discuss at your next visit. Our team can walk you through your full vaccine schedule as part of your prenatal care appointments.
Addressing Common Concerns
Despite clear evidence of safety and effectiveness, some pregnant women remain hesitant about vaccines. We understand that — and we want to have that conversation with you openly, without judgment. Common concerns we hear include worries about the impact on the baby, uncertainty about ingredients, and a general unease about receiving any medication during pregnancy.
What the evidence consistently shows is that the risk of flu during pregnancy is significantly greater than any risk associated with the vaccine itself. We're always happy to answer questions, review the research with you, and help you make an informed decision that you feel confident in.
"Dr. Maydew and the nurse were both so nice and made the visit a good experience."
– Cary OB/GYN Patient Testimonial
Schedule Your Prenatal Visit Today
If you're pregnant and haven't yet received your flu shot this season, now is the time. The providers at Cary OB/GYN are here to make sure you and your baby are protected throughout your pregnancy. We serve patients at our offices in Cary and Morrisville, North Carolina. Book your prenatal appointment online or call us at (919) 467-5941.
