Swine FLu Vaccine - Advise please.?

I am 30weeks + 4 days pregnant - I have just recevied a letter for the Swine FLu Vaccine to be carried out tomorrow...Has anyone else who is pregnant had the vaccine. What do you advise?? Gp + Midwife don't give a yes/no aswer. I am healthy/no underlying health problems...but still concerned about the whole swine flu thing but don't want to have it if it causes any side effects to the baby??? (UK)