PREGNANT NUDE YOGA 17 26 Prenatal Nude Yoga with Birth Ball - 20 Weeks 4 5 months Pregnant Now that we have my birth ball it s time to put it to good use This ball is so great for preparing the body for birth in so many ways It helps to relax stretch and strengthen the hips and core can assist in new full body stretching positions and helps tone and relax the pelvic floor