The most likely cause of an occasional decrease in menstrual flow is an endocrine imbalance during the month, but there are also other causes, such as ectopic pregnancy, that can lead to this condition. There are many reasons for endocrine disorders, such as work stress, stress, or even environmental changes, which can lead to endocrine disorders. Low menstrual flow due to endocrine disorders is characterized by a decrease in menstrual flow as expected. If there is a history of menopause and then a small amount of vaginal bleeding, it is possible that the condition is something else, such as ectopic pregnancy. It is best to go to the hospital to have a blood test for HCG, except for pregnancy-related diseases, and a gynecological ultrasound to understand the condition of the uterus and both ovaries, and then treat the condition according to the results of the test.