It may be caused by cold before or after menstruation, or it may be caused by eating cold food, or it may be caused by pregnancy and pre-eclampsia mistaken for menstruation. If this is the case, it is recommended to have a timely checkup. A blood HCG test can be performed to find out if the low menstrual flow is caused by pregnancy. If it is caused by pregnancy, a progesterone test, an estradiol test and an ultrasound test should be performed if you are planning to have a baby. If bleeding not caused by pregnancy is ruled out, an ultrasound examination should be performed to understand the condition of the endometrium and adnexa. If the endometrium is thick, progesterone can be given for withdrawal bleeding to see how the next menstrual period comes. Before and after menstruation, pay attention to keep warm and do not eat spicy and stimulating food.