It is possible for the test paper to appear dark and light when you are about to have your period, but if you have your period afterwards, the test paper will not appear dark and light. If the test paper appears dark and light when you are about to have your period, the test paper will be judged according to the test you choose. If the early pregnancy test is dark and light, it usually indicates pregnancy. 1. Early pregnancy test: If a woman has sexual intercourse and has not taken effective contraceptive measures, and usually has regular menstrual flow, when she is about to have her period, the early pregnancy test shows one deep and one shallow, which means it is weakly positive, and is mostly considered as pregnancy, but the pregnancy days are short. It is recommended to go to the hospital to have blood test to determine the HCG value. If pregnancy is confirmed, ultrasound examination should be performed at a later stage to clarify whether it is intrauterine pregnancy; 2. Ovulation test paper: before menstruation, due to the high hormone level, the result of monitoring with ovulation test paper is not accurate, if there are two lines, one deep and one shallow, it has no special clinical significance. You need to go to the hospital for an ultrasound to check the thickness of the endometrium and the follicles to determine whether you are before or after ovulation. If you want to use the test strips when you are about to have your period, you should ask your doctor for details on how to use the test strips when you buy them. In addition, the test results may be affected by various factors, so it is recommended to go to the hospital to complete the relevant tests under the guidance of a doctor.