The advice follows a frightening resurgence of the dreaded childhood disease. More than 32,000 cases, including 16 deaths, have been reported so far this year, and 2012 is on track to be the nation's worst year for whooping cough since 1959.
It's only the second time a vaccine has been advised for all women during pregnancy. Flu shots were first recommended for them in the 1990s.
The new advice was approved in a vote Wednesday by the government's vaccine advisory panel. Federal health officials usually adopt the group's guidance and promote it to doctors and the public.
Whooping cough, or pertussis, is a highly contagious disease. Its name comes from the sound children make as they gasp for breath.
Despite long-standing childhood immunizations, cases have been climbing in the past decade. Most are infants two months and younger - too young to be vaccinated because their immune systems are too immature.
Health officials increasingly have pushed to get older children and adults vaccinated, to reduce the number of carriers who might infect vulnerable infants. An estimated 30 to 40 percent of infected newborns got the disease from their mothers.
In recent years, a combination vaccine - that included protection against pertussis- was offered to women immediately after they gave birth. Then after a whooping cough epidemic in California, the panel last year recommended a one-time dose of a combination vaccine for expectant mothers, either before or during pregnancy.
But fewer than 3 percent of pregnant women have gotten the vaccination, according to the Centers for Disease Control and Prevention.
Worse, recent research has shown the whooping cough vaccine's protection doesn't last as long as previously thought. A recent study found women vaccinated within two years of their pregnancy had relatively few antibodies to pass on to their newborns. That included women vaccinated early in their pregnancy, said Dr. Mary Healy, the Baylor College of Medicine researcher who led the study. That suggests women need to be vaccinated during the third trimester for it to really have an effect, she said.
Despite the overwhelming vote tally, several members of the panel voiced uneasiness with a lack of data on how effective and safe such a recommendation will be for mothers and newborns.
CDC officials acknowledge they have data on only hundreds of women who got the shots during pregnancy. What's more, the vaccine is only licensed to be given to adults once. Under the new recommendation, women who raise large families may be getting the vaccine three or four or more times.
But CDC experts repeated there's no evidence of serious risk to either mothers or newborns. And they estimated that enacting the recommendation could reduce whooping cough cases by 33 percent, hospitalizations by 38 percent and deaths by 49 percent.
"The benefits of vaccination outweigh the theoretical risks," said Jennifer Liang, a CDC epidemiologist who presented the benefit estimates to the panel.