Pregnant women should be offered the flu vaccine at any stage of pregnancy. It is safe to have the flu vaccine during any trimester, from the first weeks through to labor. However, some recommendations note offering it from around 22 weeks pregnancy to optimize protection for both mother and baby. Vaccination is encouraged as soon as possible during pregnancy to allow time for the mother to pass protective antibodies to the baby, even if the baby is born prematurely. The vaccine protects the pregnant woman from flu complications and also provides newborns with immunity in their first months of life.

Key Points on Timing and Safety

• Flu vaccine can be given safely at any stage of pregnancy (first, second, or third trimester).

• Some countries recommend vaccination starting from around 22 weeks gestation to balance maternal and fetal protection, but it is not restricted to this window.

• Vaccination helps protect both mother and baby, reducing flu risks, complications, premature birth, and low birthweight.

• The vaccine used is inactivated (not live), making it safe for pregnant women and their babies.

Professional Guidelines

• The CDC, ACOG, and WHO recommend flu vaccination at any time during pregnancy, emphasizing early vaccination within the flu season.

• Receiving the vaccine earlier in pregnancy or during the flu season maximizes protection for both mother and newborn post-birth.

Therefore, pregnant women should be offered the flu vaccine as early as possible during pregnancy, regardless of the trimester, with some focus on starting around 22 weeks if following specific national guidelines. This advice supports both maternal health and newborn protection against influenza.