Leukorrhea is a physiological manifestation of a woman in ovulation, when she should experience a decrease in leukorrhea before her normal menstruation. The greater the likelihood that the leucorrhoea appears before menstruation is that ovulation is pushed back. The physiological cycle can be affected by the external environment, and normal ovulation in women will come 14 days before the arrival of the next period. When the body’s hormone level changes, the external environment such as cold, emotional changes, the impact of strenuous exercise, there may be ovulation pushed back, before the arrival of the menstrual period appears white belt pulling, the corresponding time of the arrival of the menstrual period appears pushed back the probability is relatively high, need to be combined with the regularity of the menstrual cycle.