Yellowing of the leukorrhea and delayed menstruation are not necessarily a sign of pregnancy, as pregnancy does not cause yellowing of the leukorrhea. If possible, you should buy a pregnancy test to rule out the possibility of pregnancy, because environmental stress, mental factors, and hormonal changes in the endocrine system may cause delayed menstruation. And before menstruation, due to the body’s hormone levels, especially progesterone will be more vigorous, will cause the vaginal shedding cells become more, which will cause the leukorrhea is milky white or yellow viscous secretion. There may be some normal physiological manifestations, and not all intercourse can cause pregnancy. As far as possible through the laboratory to determine whether there is pregnancy, simply through some of the performance, there is no way to judge, there will be a certain error.