Delayed menstruation and weight gain can be caused by a variety of factors, including physiological factors, such as pregnancy, and pathologic factors, such as polycystic ovary syndrome. 1. Pregnancy: If a woman has a recent history of sexual intercourse and experiences delayed menstruation and weight gain, she needs to consider the possibility of pregnancy. 2. Polycystic ovary syndrome: If the patient has polycystic ovary syndrome, affected by the abnormal secretion of sex hormones in the body, the patient may show abnormal menstruation, such as scanty menstruation, scanty menstruation, or even amenorrhea, and may also be accompanied by weight gain, acne and other conditions. There may be other reasons for delayed menstruation and weight gain, so it is recommended to consult a doctor in time, complete the relevant examinations, clarify the cause of the disease under the guidance of a professional doctor, and target treatment.