I'm currently BF through my second pregnancy and tandem feeding this time. I initially noticed an increase in supply then settled down to normal without the huge letdown feeling I usually get. Supply wasn't as great pre pregnancy but probably notice most significant drop around 20weeks when DD will actually comment at times that it "nempty". DS will feed but not be as relaxed and want either longer feeds or quicker more frequent feeds where he will be really rough and fussy, with you know the whole trying to do BF gymnastics of some sort. As DD has dairy intolerance I just offer cups of rice milk afterwards or at different times or before a feed to make him more relaxed I Also still have some EBM in the freezer so offer that too at times.