Ovulation test paper color is very light to prove that it is weak positive, this time intercourse may also be pregnant. The principle of ovulation test is to monitor the level of luteinizing hormone in the body to determine whether a woman is ovulating or not. In the middle of menstruation, the secretion of luteinizing hormone will increase faster, forming a peak, usually within 24 hours of ovulation. When a woman is in the safe period, the ovulation test paper is negative, and when she is approaching the ovulation period, the ovulation test paper will change from weakly positive to positive and strongly positive, that is, the color will change from light to dark. If a woman ovulates, luteinizing hormone will drop, and then it will change from positive to weakly positive and then to negative. The test paper will gradually change from dark color to light color. Therefore, if the color of the test paper is light, it is possible that you are about to ovulate, or you have already ovulated, so it is possible that you will get pregnant if you have intercourse at this time.