Many think of it as 'sticking.' implantation in humans always occurs when the embryo is between 6-7 days old. A very popular concept on the internet now in 2012, 'implantation bleeding, ' is speculative and mostly not useful.
Also, urinary stones can form in the bladder lining due to an accumulation of debris and chemicals. Broken blood vessels can cause blood in the urine, often because of torn or enlarged veins on the inner surface of the prostate. Blood in the urine also can be caused by the sudden stretching of the bladder wall.
Enlargement of the prostate is usually a benign condition, called BPH or benign prostatic hyperplasia. Prostate cancer may present with enlargement, but it is often an infiltrative process that first spreads within the prostate gland and may later produce nodules that can be felt by rectal exam.