I think prenatal should really be continued, and then if you plan to breast feed as well. For both baby and yourself and why not! They make my hair and nails grow like crazy :).
My wife's midwife suggested not taking any prenatal vitamins with omega 3 in it for the final month or so because it is a blood thinner and can increase the risk of hemorrhaging during delivery. (Mothers health, not babies.) You probably should ask your doctor though.
I've stopped taking mine and I'm 29 weeks, changing my diet slightly to get all the vitamins I need naturally, which has got to be better for not only baby but yourself aswell :)