The part in parenthesis answers the question... YES, Thimerosal is in the vaccine, and it is a MERCURY based preservative.
Does the 2009 H1N1 flu shot have mercury in it?
There is no evidence that thimerosal (a mercury preservative in vaccine that comes in multi-dose vials) is harmful to a pregnant woman or a fetus.
However, because some women are concerned about thimerosal during pregnancy, vaccine companies are making preservative-free seasonal flu vaccine and 2009 H1N1 flu vaccine in single dose syringes for pregnant women and small children. CDC advises pregnant women to get flu shots either with or without thimerosal.Full Q&A page from CDC