Crotch pain is a very common clinical symptom of pregnant women during pregnancy, and this symptom usually occurs in the middle and late stages of pregnancy. The main causes of crotch pain are: 1, the role of relaxin, after pregnancy, the female endocrine system will undergo significant changes, the body will secrete relaxin. Under the action of relaxin, the ligaments of each bone and joint will become relaxed and the mobility of the bone and joint will increase accordingly. The hip joint area ligament relaxation will lead to the symptoms of hip pain. 2, osteoporosis, osteoporosis is the main reason for the symptoms of hip pain after pregnancy. The symptoms are relatively light for pregnant women who take calcium supplements on time during pregnancy, and the symptoms of crotch pain are more pronounced for pregnant women who have not been taking calcium supplements. 3, poor lifestyle habits, poor lifestyle habits during pregnancy, prolonged sedentary or standing, walking for too long, can cause and aggravate crotch pain.