Pregnancy and the Flu

PD_Medicine and Healthcare_MHE_046 Approximately 36,000 people in the United States die each year as a result of complications of influenza (the flu). Research has shown that pregnant women are at increased risk for serious complications of the flu. Since the best way to protect against the flu is to get vaccinated before flu season, the Centers for Disease Control and Prevention (CDC) recommends that all women who will be pregnant or are pregnant during the flu season be vaccinated.

A number of factors make pregnant women more susceptible to complications associated with the flu. For instance, pregnant women’s hearts are working harder, they have decreased lung capacity, and their immunity may be compromised.

But if you get the flu while you are pregnant, keep in mind that it rarely causes birth defects. You are in more danger of becoming seriously ill than your baby. If you experience flu symptoms (fever over 101ºF, chills, sweating, muscle aches, headache, runny nose, cough, sore throat, watery eyes, sensitivity to light), call your doctor. With proper care, serious complications can be prevented.

Is the Flu Shot Safe During Pregnancy?

A study published in the International Journal of Epidemiology followed approximately 2,000 women who had been vaccinated with the flu shot and found no adverse effects to the fetus associated with the vaccine.

A study published in the April 2005 issue of the American Journal of Obstetrics and Gynecology, looked at 252 women who received the flu shot during their second or third trimester. Researchers found that there were no adverse effects on pregnancy outcomes associated with the flu shot.

The CDC has approved use of the flu shot, which contains an inactivated flu virus, for pregnant women. However, the nasal-spray flu vaccine, which contains live, weakened flu viruses, is not approved for pregnant women. So if you are pregnant, make sure you get a flu shot, not the nasal spray vaccine.

Getting a Flu Vaccine

Since the flu season in North America can begin as early as October and last as late as May, October is the best time to get a flu shot, but you can still get vaccinated as late as December (and later). If you are pregnant or plan to become pregnant during this year’s flu season, talk to your doctor in advance about getting a flu shot. It's important to note that, in some years, there is not always enough vaccine for everyone who needs one, especially early in the season. However, the CDC and state public health departments invariably include pregnant women in a "priority category."

Once vaccinated, you most likely will have no serious problems. However, complications may occur. Minor side effects include soreness, redness, or swelling at the injection site; low-grade fever; and aches. More serious complications, such as severe allergic reactions, may occur on rare occasions.

On a final note, a study in the American Journal of Epidemiology estimated that an average of one to two hospitalizations could be prevented each year for every 1,000 pregnant women who get the flu vaccine.