Vaginal relaxation refers to the reduction of the tension of pelvic muscles, which relaxes the muscles around the vagina and widens the vagina. There are many reasons for postpartum vaginal relaxation. The fetus is too big (the head is too big), which causes birth injury during natural delivery. Vaginal injury caused by mid-term induced labor; Several deliveries; Lack of exercise after delivery; Postpartum recovery blindly lose weight, neglect nutrition or overwork, resulting in poor pelvic muscle recovery and so on.

For mothers who give birth naturally, because the fetus is delivered through the vagina, the head diameter of the baby born generally is about 10 cm, that is, the vagina should be expanded to 10 cm during delivery (the normal vaginal diameter is 2.5 cm). After being squeezed by the born child, the vagina is obviously expanded, the muscles and hymen traces are completely destroyed, and the elasticity is obviously reduced. However, although the vagina of the mother who gave birth to the fetus from the vagina has changed, there will be different degrees of vaginal relaxation. However, it does not mean that natural childbirth is the chief culprit of vaginal relaxation, because during labor, the pelvic muscles and ligaments will be fully stretched to prepare for the birth of the baby. Therefore, even a mother who has a caesarean section will have a loose vagina.