The pelvic floor muscles are under enormous strain during pregnancy and have to stretch to allow the birth of baby. Weak pelvic floor muscles can lead to problems of bladder and bowel control, allow pelvic organs to sag (prolapse) and reduce sexual pleasure. Strengthening exercises are therefore very important both before and after birth. Signs of weak pelvic floor muscles include stress incontinence (leaking of urine when coughing, sneezing or laughing, inability to keep a tampon in place and vaginal flatulence. One in three women who have a baby develop some degree of incontinence.