It is possible for the pituitary gland to cause menstrual irregularities because the function of the pituitary gland is to control and maintain the body’s endocrine secretions. If there is an abnormality in the pituitary gland, such as a pituitary tumor, it can lead to changes in the sex hormones, such as increased prolactin, abnormal estrogen and androgens, which can affect the normal menstrual pattern and lead to irregular periods. Irregular menstruation can be caused by many reasons, so whether it is caused by the pituitary gland or not, further examination is needed. If there is a significant increase in prolactin, it is very likely that there is a pituitary tumor, because the most common type of pituitary tumor is the prolactin-type pituitary tumor, which can cause an increase in prolactin and thus affect the regularity of menstruation, and further MRI and enhanced MRI of the pituitary gland can be done to determine the diagnosis. If the tumor is not large and the increased prolactin can be treated with oral bromocriptine, the larger tumor needs to be removed through surgery.