Generally, you need to do some routine examinations before you can apply for a health certificate. If you check the urine routine during menstruation, there may be menstrual blood mixed with urine, which will lead to positive urine routine and affect the accuracy of urine routine. Therefore, it is best to check and apply for a health certificate after the menstruation is completely clean for 3 to 7 days. If the health certificate doesn't need urine routine and leucorrhea routine, it can be done at any time.