Why after 15 days of menstration why come back...

What is the treatment for irregular mensural cycle
first of all the normal cycle between 22-32 day so if your menstural cycle between this time ypur period is normal and you donnt need any medication and you must go away of stress and eat good nutrition and do routeinly soprt but if your period more than normal you can take duphaston tab two pills daily for 10 days, with psychological and mental comfort and avoiding stress and anxiety, and regular eating healthy, rich in vitamins and essential elements for the body, with a lot of drinking water daily, treatment of chronic diseases such as thyroid problems ,and Pelvic inflammatory diseases
What are the investigation required
Clinical examination of the patient by the obstetrician-gynecologis , and Complete blood count , and Ultrasound on the ovary and utreus
What are the causes of irregular menstrual cycle
Stress
Anxiety
Exhaustion
Emotional instability
Hormonal disturbance
PCO polycystic ovary
Thyroid dysfunction
Pelvic inflammatory diseases
Endometritis
my advise
Regularly take the previous treatment, see a doctor if the menstruation continues to be irregular