i agree with the other ladies,
pumping while still pregnant won't do anything for breastfeeding,
and if your body is not accustomeed to the nipple stimulation, it cna help get labor started naturally. oxytocin is released when the niples are stimulated. oxytocin is the natural hormone that has been synthesized that they call "pitocin" to jump-start or speed upp labor in hospitals.
if you have nursed through your pregnancy, ignore most of the above though, becuase your body is accustomed to the stimulation.
as for leaking while preggie,. i leaked like crazy with #1 and nto at all with #2, and had more than enough milk both times.
congrats on your upcoming little one, and welcome to the bf board