A Shot of Prevention: The Flu and Pregnancy

Pregnancy tends to weaken the immune system, leaving you more susceptible to illness and various infections. Drinking lots of fluids, something all pregnant women should already be doing, can often help prevent the onset of the flu or alleviate symptoms. "The main complication from the flu in pregnancy is dehydration, which can cause preterm labor and delivery," explains Dr. Maura Parker Quinlan, MD, assistant professor of Obstetrics and Gynecology at the University of Chicago Hospitals in Illinois. "If the mom gives the flu to her newborn infant, it can cause a serious and potentially life-threatening infection in the newborn," she says.

When expecting women are diagnosed with an influenza infection particularly in the second or third trimester, they are "at high risk for developing serious complications that can impact their health and that of their baby," says Dr. Neil Silverman, MD, medical director of Inpatient Obstetric Services at Cedars-Sinai Medical Center in Los Angeles, California. It is important to note that any type of infection can lead to preterm labor, and influenza infection in pregnancy can progress to more dangerous infections such as pneumonia. (Pregnant women with the flu are at high risk for developing pneumonia and are more often hospitalized from complications of the flu than non-pregnant women of the same age.)

The Flu Shot

The most effective way to prevent exposure to the flu virus is through vaccination. Since the influenza season can occur anytime between October and March, this is the most appropriate time to be inoculated against the virus. Dr. Homsi explains that this will "assist in allowing the immunity to peak during the height of the influenza season," and he adds, "It usually takes about one to two weeks for the flu shot to take effect."

After vaccination, your body will begin to produce essential antibodies that will protect you and your unborn baby against exposure to the virus. "When women are vaccinated during pregnancy, it has been demonstrated to transfer immunity from mother to baby, which reduces the risks for a baby born during the flu season," says Dr. Silverman. Dr. Homsi agrees, adding that, "studies have shown that those antibodies can last for at least two months after birth and they [continue to] help prevent the baby from getting the virus." Since flu viruses are known to change from year to year, you need to be inoculated each year. (Unfortunately, the flu shot you had last year cannot protect you during the flu season this year!)