Pregnant Women Especially Vulnerable to Swine Flu

July 28, 2009— -- Pregnant women may be reluctant to receive vaccines, especially brand-new ones, while they're expecting, but today, mom-to-be Sivan Berman-Marciano said she'll opt for a swine flu vaccination if her doctor recommends it.

"If it's going to help not to have the swine flu and keep my baby safe, I will take it," Berman-Marciano said.

"I'm much more worried now than I was before getting pregnant because now, it's not only me, it's the baby also," she added.

Today, many doctors say that's the right move and argue that pregnant women should be given first dibs if a swine flu vaccine becomes available as expected this fall.

Watch "World News With Charles Gibson" tonight at 6:30 ET for the full report.

The conversation comes as a federal vaccine advisory panel meets tomorrow to further discuss who should receive top priority for the swine flu vaccine. It also coincides with increasing concerns that pregnant women are particularly vulnerable to the pandemic.

Any flu virus can be dangerous for a pregnant woman, but swine flu appears to be especially threatening.

According to data from the Centers for Disease Control and Prevention, 15 out of 266 swine flu deaths in the U.S. so far have been among pregnant women. That's 6 percent of total fatalities, even though pregnant women only make up 1 percent of the population.

The flu can be particularly deadly in the second and third trimester of pregnancy, both for mother and baby.

Today, Dr. Jacques Moritz, director of gynecology at New York's St.Luke's Roosevelt Hospital, said that's because a pregnant woman's weakened immune system makes her especially susceptible to the virus.

"What the body does, and what the baby does, really, is it sends out a message, 'Don't get rid of me,'" Moritz said. "So it brings down the immune system, so you don't reject the fetus."

He added, "Anybody that is going to be pregnant, in the second or third trimester during this upcoming flu season, should get vaccinated before, obviously, the flu season."

Visit the ABC News OnCall+ Swine Flu Center to get all your questions answered.

Learn about swine flu's symptoms and find out if you need to see a doctor.