The vast majority of women have relatively high menstrual volume on the second day of their period, and it is the day when the volume is high during the whole menstrual time. If the volume is particularly low on the second day, it is often caused by the following reasons: 1. not paying attention to daily life and drinking too many frozen drinks, which contract the uterus and cause a sharp decrease in menstrual volume. 2. taking some estrogenic drugs to make the uterine lining repair as soon as possible, so it will cause a sudden decrease in menstrual volume. 3. because no special attention is given in daily life, on the second day of menstruation The sudden emotional shock or cold stimulation can also reduce the menstrual flow. 4. To rule out pregnancy or ectopic pregnancy in this case, it is recommended to have a blood test for HCG.