Pregnant women experience changes in their organs and immune system that make them susceptible to serious flu infections.
An international study now shows that flu vaccines can help prevent them from coming to the hospital.
About half The Clinical Infectious Diseases journal reports that flu vaccines could reduce the risk of hospitalization by about 40 percent.
Based on medical records of 2 million pregnant women researchers found that the vaccine helped regardless of the trimester and also protected those with other conditions such as asthma and diabetes.
During the study, 80 percent of subjects were pregnant during a flu season, suggesting that future mothers will likely be attacking the flu while they await.
The disease control and prevention centers that co-authored the study say that flu vaccines in pregnant women have a good safety record, but added that they should not receive the nasal spray vaccine.