CDC warns that more pregnant women should get the flu shot: What to know

Not enough pregnant women are getting the flu vaccine and it's putting themselves, their babies and the public at risk, according to a new report from the Centers for Disease Control and Prevention (CDC).

Pregnant women have more than double the risk of hospitalization compared to non-pregnant women of childbearing age if they get influenza, but getting a flu shot reduces a pregnant woman's risk of being hospitalized due to influenza by an average of 40%, according to data shared by the CDC.

In addition to the flu vaccine helping pregnant women, it can also help their babies because the vaccine passes on antibodies to the fetus that provide protection after birth, when babies are too young to be vaccinated themselves, according to the CDC.

"It is the best way for that woman to protect not just herself, but her unborn baby because that baby cannot get vaccinated for six months," ABC News chief medical correspondent Dr. Jennifer Ashton said Wednesday on "Good Morning America." "So she will be able to protect her baby by passing those antibodies while she’s pregnant."

Children under 5 years old have the highest likelihood of being hospitalized for the flu. A total of 186 pediatric deaths were reported to CDC during the 2017-2018 flu season, the most recent available data.

Flu rates typically peak in the U.S. between December and February. People who are at most risk for flu complications include children, pregnant women, people over 65, those with chronic medical conditions and nursing home residents, according to Dr. Naomi Kaplan, a resident physician in physical medicine and rehabilitation and a member of the ABC News Medical Unit.

With the 2018-2019 flu season already well underway, here are four things pregnant women need to know about the vaccine.

1. Vaccination during pregnancy is safe: “Vaccination during pregnancy is safe and we have a lot of reassuring data to back that up,” Dr. Christopher Zahn, vice president of practice activities for the American College of Obstetrics and Gynecology (ACOG), told "GMA" in a statement.

2. Flu vaccines are safe during any trimester: The CDC recommends that all pregnant women should get a flu vaccine during any trimester of each pregnancy.

3. Pregnant women need the whooping cough vaccine too: The CDC recommends that all pregnant women get the whooping cough vaccine (Tdap) during the early part of the third trimester of each pregnancy as part of routine prenatal care.

4. Flu vaccines are available outside the doctor's office: The flu shot is available in both doctors' offices and in drug stores. Women whose health care providers offered or referred them for vaccination had the highest vaccination rates, according to the CDC.