There’s a new reason for pregnant women to keep themselves healthy this flu season. A study suggests their health while pregnant can have major implications for their children’s health later in life.

Researchers at the University of Southern California say children whose mothers were infected with the flu while pregnant are at a higher risk for developing heart disease later in life, according to Reuters.

They studied health records from the 1918 flu pandemic and found girls whose mothers had the flu during the first trimester were 17 percent more likely to have cardiovascular problems after age 60 than girls whose mothers were healthy early in pregnancy.

Boys, on the other hand, were 23 percent more likely to have heart disease in adulthood if their moms were sick during their second or third trimesters.

The study is important as the medical community gears up for what’s expected to be a difficult flu season, with both the seasonal virus and the H1N1 "swine flu" virus expected to sicken millions around the world.

Pregnant women are urged to get vaccinated against the flu since they are at a high risk for complications of the virus. Health officials say fewer than 25 percent elect to have the flu shot, however.

Vitamin C, vitamin D, zinc, echinacea and probiotics are all believed to boost immunity and help avoid viruses like the flu.