There is no difference between leucorrhea before pregnancy and leucorrhea before menstruation, both are due to the increase of estrogen secretion level in the body, and the phenomenon of increased leucorrhea, but the color and smell of leucorrhea do not change abnormally, so clinically there is no way to determine whether a woman is pregnant or about to have her period through leucorrhea. However, if a woman has delayed menstruation and has increased leucorrhea and has had normal sexual intercourse, she should go to the hospital for an early pregnancy test to rule out pregnancy. If the early pregnancy test is negative, it may be a sign that the woman is about to have her period. Whether a woman is pregnant before her period or has fishy smelling leukorrhea, or is accompanied by itching of the vulva and yellowish color of the leukorrhea, it may be caused by gynecological inflammation and should be brought to the attention of the patient.