But several news studies find getting a seasonal flu vaccine while pregnant protects newborns from the flu for months after birth. Experts say it won't cause a miscarriage.
Newborns enter the world without protective immunity and can't get the flu vaccine until they are six months old. But, if mom gets it while pregnant, they also get protection.
The latest data on the safety and effectiveness of these vaccines was presented at the annual meeting of the Infectious Diseases Society of America.