Hi Dr, am currently 5 and half week pregnan, Confirmed by blood and urine test, this is my 2nd pregnancy, my 1st pregnancy am expirence implantation bleeding along with lower back pain and all the period cramps,, after that my pregnancy confirmed.. (but don't know when means which week it happened..) But my 2nd pregnancy am still not expirence any implantation bleeding,but happend all the lower back pain and cramps in 2nd 3rd week.. but my pregnancy positive.. Can implantation can happend without bleeding.or spotting .??