you can purchase batting that does not shrink- many people use fusable fleece or the thinnest batting they can find for table toppers-
most batts do have instructions on the packaging for pre-shrinking if you really feel it's necessary
also the more quilting done the less shrinkage occurs....so densly quilting will keep shrinkage to a minimum.
what ever batting you have you should follow the instructions on the package though- they are all different- and i could tell you one way-and your batting could come out shredded- a horrible mess-
i never ever deal with pre-shrinking- i read the packages before i buy them and buy the one that works best for my project
i usually make runners for my mom & aunt- they like them to stay really flat- i use inexpensive single sided flannel i pick up for $1 a yard- that i do pre-wash- and dry in a hot dryer- then i use it for batting- works out great.
different batts shrink different amounts- or not at all- and have different (lofts) , quilting recommendations- choose the batt that works best for your project-
the packaging contains a wealth of information (including pre-shrinking instructions)