Flu Shot while Pregnant

Pregnancy weakens the immune system ^[1], leaving the expectant mother exposed to various viral and bacterial conditions, with flu or influenza being one of the most common one. What is worse is that flu increases your risks of having a premature labor and delivery along with some more serious potential complications like bronchial infections, pneumonia and meningitis ^{[2, 3]}.

Should pregnant women get the flu shot

The Center of Disease Control and Prevention, as well as American Congress of Obstetricians and Gynecologists recommend all pregnant women to get vaccinated before the flu season to prevent the complications associated with it ^{[4, 5]}.

Studies have shown it to be safe to take the flu shot any time during the first trimester ^[6] as well as the second and third trimesters ^[7]. The virus in the vaccine is dead, so it cannot harm the mother or the baby in any way ^[8]. In fact, when you get vaccinated, the antibodies produced by your body passes through the placenta to your unborn baby and protect him against the flue for about the first six months of his life ^{[9, 10]}. According to studies, babies born to mothers who did not take the vaccine were shown to have no such antibody protection from the flu virus ^[11].

Additionally, a recent study suggests that women who receive the injection are less likely to experience a stillbirth than those who do not ^[12].

However, only the injection form of the vaccine containing dead virus is considered safe during this time. The nasal shot is not recommended for pregnant women as it contains weakened live virus ^[24].

Are there any risks of taking a flu vaccine during pregnancy

Is it associated with increased chances of miscarriage

The vaccine is sometimes erroneously linked with a higher chance of miscarriage. But studies have shown that women who took the injection during the first trimester were no more at risk of a miscarriage compared to those who did not take it ^[11].

Does taking a flu shot when pregnant make you more likely to have a baby with autism

The influenza vaccine contains thimerosal, a preservative with small mercury content, which is believed to be associated with a higher risk of autism in your baby. However, studies have failed to find any association between getting the flu shot while carrying and giving birth to a baby with any developmental disorders, like autism ^[13].

Moreover, a study published by the Pediatrics journal suggests that babies born to mothers who have had a fever or flu for over a week during pregnancy are slightly more likely to have autism spectrum disorder after birth ^{[14, 15]}.

Can the thimerosal in the flu shot be harmful for you and your baby in any other way

Since the vaccine contains only trace amounts of thimerosal, it is usually no cause of concern. Researches have shown no evidence of any harmful effects of thimerosal exposure in a flu shot, with both ACOG and CDC stating that the thimerosal in the vaccine is safe for pregnant women and their babies ^{[13, 16]}.

The preservative is necessary in case of multi-dose vials to prevent the vaccine from getting contaminated every time a dose is drawn ^[17]. Thimerosal-free single dose vials are also available in case you still want to avoid it ^[4].

What are the side effects of a flu shot during pregnancy

The side effects after getting the injection are usually the same for pregnant women as they would be for anyone ^[18], with the common ones including:

Soreness, swelling and pain around the area of the injection
Low grade fever
Drowsiness
Nausea
Muscle aches
Headache

None of these symptoms last for over a couple of days and do not usually need any treatment ^[9]. Some women may develop some more serious allergic reactions, such as skin rashes, breathing problems and dizziness, in a few rare cases ^[19].

Who should not get the flu shot

Those who have had some allergic reaction to the vaccine in the past and those with an egg allergy should inform their doctor before getting the vaccine. It contains small amount of egg protein which might cause adverse reactions if you are allergic to egg ^[20]. Your doctor may a recommend the egg-free vaccine in such cases ^[21].

A history of Guillain-Barré syndrome, a nervous system disorder, also calls for you to consult your doctor before getting the shot ^[22].

Can breastfeeding women get the flu shot

It is safe for nursing mothers to get the flu shot ^[3]. The antibodies produced by the mothers body passes to the baby through breast milk, protecting the baby from influenza as well ^{[7, 23]}.

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