The link above goes to a great blog post about the flu vaccine and pregnancy, and the ways the media and medical professionals play on a mother's love for her baby to persuade her to get the vaccination.
Here's a short part of the post, a warning label from one of the manufacturers of the flu vaccine:
“Pregnancy Category C: Animal reproduction studies have not been conducted with Influenza A (H1N1) 2009 Monovalent Vaccine or Fluzone vaccine. It is also not known whether these vaccines can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Influenza A (H1N1) 2009 Monovalent Vaccine should be given to a pregnant woman only if clearly needed.”
The post also outlines other means by which you can prevent the flu.
I personally don't recommend the flu vaccine during pregnancy, and I think that expectant parents should seriously consider all the facts before making a decision.
For more information about the flu vaccine, please see the following: