If your bruises are in the labia/vulva region near the anal area it could mean that there is too much pressure and the cutout helps eleviate the pressure as the skin there is very sensitive.
Another source could be how you have your saddle tilted which could be putting extra pressure on the region. Aslo, on long rides-less padding on the saddle is better (again, because of the pressure issue).
I know some amount of bruising in normal during the early part of the season-esp. with distance rides. I always try to rule out other issues such as saddle tilt, shape, etc.