There are many factors which are responsible for irregular periods some of them you can find in following article.
* A woman can have irregular periods due to significant weight loss or weight gain.
* Over exercise can also result in irregular menstruation.
* Poor nutrition and diet which is rich in carbohydrates is also related to hormonal imbalance and menstrual disturbances.
* Some drugs can also cause irregularities in menstruation.
* Many women who are smokers experience irregular periods.
* Excessive intake of coffee is also a cause of irregular menstruation.
* Some specific drugs can also cause menstrual irregularities.
* Use of excessive alcohol can also disturb hormonal metabolism which also disturbs menstrual cycle.
* Drug abusers can also have some irregularities in their periods.
* Some eating disorders like bulimia nervosa and anorexia nervosa also cause menstrual cycle irregularities.
* In some cases increased stress is cause of irregular menstruation.
* A disease called Polycystic Ovarian Syndrome can cause estrogen dominance in the blood which can be the cause of irregularities in the menstrual cycle.
* One of the cause can be uterine abnormalities like polyps, cysts, fibroids and endometriosis.
* Recent child birth or miscarriage are also one of the causes of irregularity.
* Some women have period irregularities when they breast feeding.
* There can be some changes in menstrual cycle if there is beginning of menopause in a woman.
The above reasons can cause irregularities in menstrual cycle. If you find some reasons of irregular periods in yourself or your relatives and friend then it is a good idea to visit your doctor.