The main reason why fat people don’t have their periods for months is abnormal uterine bleeding due to anovulation. Women with obese weight are prone to have a combination of polycystic ovary syndrome, which tends to cause anovulation, which can lead to delayed menstruation. Menstruation is defined as the proliferation, shedding and bleeding of the uterine lining accompanied by cyclic changes in estrogen and progesterone secreted by the ovaries, and without normal ovulation, there will be no normal menstruation. This situation requires progesterone withdrawal bleeding to have a normal menstruation, and subsequent treatment includes medication and weight reduction. medication includes two kinds of treatment, i. progesterone post-half cycle treatment; ii. oral short-acting contraceptives, such as Daying-35. in addition, the most important thing is to control the weight.