What are the natural causes of an irregular period besides being pregnant?

Irregular periods: If a woman is not ovulating regularly she will not have regular periods. Many things can affect a woman's ovulation cycle: stress, body weight, thyroid function, polycystic ovary syndrome (pcos), and others. Maintaining a normal body weight may be helpful. Beyond that, medical evaluation is often necessary.

Causes: Reasons for irregularity include weight gain or loss, breastfeeding, alcohol use, eating disorders, marked emotional stress, endometriosis, uterine fibroids, cervical polyps, polycystic ovarian syndrome, excessive exercise & pregnancy. When a girl has just started menstruating & around the time of menopause periods can be irregular.