Yes, you should get a flu shot if you're pregnant or breastfeeding

• You can and should get a flu shot while pregnant, and the best time is in October for the US.
• The flu shot protects both the mother and baby against the flu virus after birth.
• You can still get the flu after a flu shot, so if you're pregnant and get sick, contact a physician.

Expectant mothers are at an increased risk of developing complications from the flu, so a flu shot is especially important if you're pregnant.

Here's what you need to know about getting the flu shot while pregnant.

Yes, you can get a flu shot while pregnant

The best time to get your flu shot is in October, which is early in the flu season, says Laura Riley, MD, an obstetrician and gynecologist-in-chief at NewYork-Presbyterian/Weill Cornell Medical Center.

It doesn't matter which trimester you're in, or if you're carrying twins, quintuplets, or a single baby, doctors say that the flu shot is safe to get at any point in your pregnancy as well as when you're breastfeeding.

Why you should get a flu shot while pregnant

"The flu is usually a self-limiting infection in healthy people, but can be dangerous and even life-threatening in certain high-risk people, including pregnant women," says Mia Di Julio, MD, OB-GYN at Providence Saint John's Health Center.

Because of their weakened immune system during pregnancy, expectant mothers are at a greater risk of developing life-threatening complications from the flu, such as severe pneumonia, preterm labor, or severe respiratory distress, Di Julio says.

The flu shot protects the baby, too

Some women are hesitant to receive the vaccine because they're unsure how it will affect the fetus, yet the evidence is clear that the flu shot is safe during pregnancy and does not cause birth defects or other complications with fetus development.

Doctors strongly recommend getting the flu shot while pregnant because it's critical to protecting the baby once the baby is born. That's because when a woman gets the vaccine while pregnant, she passes her flu-fighting antibodies to the baby through her placenta.

This is important because newborns are too young to be vaccinated and have to wait until they're 6 months old. That means in the first six months after birth, a baby's only protection against the flu is the antibodies gained from mom while still in the womb.

Which flu vaccine to get while pregnant

Pregnant women should receive the inactivated influenza vaccine, which is delivered by injection. They should avoid the nasal spray vaccine because the spray contains a live virus, which could cross the placenta and cause an infection in the fetus.

Side effects of the flu shot are the same for pregnant women as they are for anyone else, Riley says. They include soreness at the injection site, fatigue, and headache that can last for up to two days after receiving the vaccine.

Though rare, flu shots can cause allergic reactions, and a pregnant woman shouldn't receive a flu shot if she is severely allergic to a component of the vaccine, like an allergy to eggs.

Generally, people with egg allergies can get the flu vaccine, even if they are pregnant. However, for those with a severe egg allergy, the CDC recommends that the vaccine is given in a medical setting, such as an allergist's office.

And if there's still some concern, consult a doctor about whether you might be eligible to receive another form of the vaccine.

What to do if you still get the flu while pregnant

Getting a flu shot helps lower your risk of contracting the flu, but it isn't a guarantee that you won't catch it. If you're pregnant and you do get the flu, don't panic, Riley says. Contact your doctor as soon as you notice symptoms and get an antiviral agent to treat the flu.

Insider's takeaway

People who are pregnant or breastfeeding should get the flu shot. The only exception is if a person is severely allergic to an ingredient in the vaccine, like eggs.

The best time to get your flu shot is early during flu season, right around late September or early October. Just remember that it takes about two weeks for your body to produce antibodies against the influenza virus.

Therefore, you are still vulnerable to infection for those two weeks after receiving your shot, and you should take the necessary steps, like washing your hand regularly and wearing a mask in crowded spaces, to protect yourself against illness during that window.

If you get the flu while pregnant, contact your physician immediately to get proper treatment.