Irregular menstruation a few years after childbirth may be caused by endocrine disorders, or uterine fibroids, endometrial lesions, etc., which need to be analyzed specifically. 1. Endocrine disorders: polycystic ovary syndrome, hyperprolactinemia, decreased ovarian function, Schihan’s syndrome and other endocrine disorders can lead to irregular menstruation. 2. Uterine lesions: diseases such as uterine fibroids and endometriosis can also affect the normal proliferation and shedding of the uterine lining, leading to irregular menstruation. There may be other reasons for irregular menstruation a few years after childbirth, so it is recommended to go to the hospital for relevant examinations to clarify the causes of irregular menstruation and then treat the symptoms.