One thing that I haven't read anywhere about the third of fourth pregnancy is how differently you carry the baby by the ninth month. This time I feel like someone lodged a bowling ball in between my legs. It is the oddest feeling in the world. I feel like I am walking on my baby's head! This is not how I felt with the other pregnancies. Sure I felt pelvic pressure, but never this low!! I can hardly walk. If I take to wide of a step I feel that pressure and it feels unnatural. I called my doctor and was told that was normal if you have had more than two pregnancies. Your body doesn't hold the baby as high anymore causing that bowling ball in a bag feeling.
Ways to prevent that from happening: kegel exercises and yoga! Good physical therapy also works.