On the fifteenth day of ovulation, if the test strip has only a light mark, it means that there is no pregnancy, or the time is early, the HCG concentration is low, and it has not been shown; if the control strip does not show it, it may also be the quality of the test strip or the method of measurement is wrong. If the control strip shows and the test strip is shallow, it usually indicates pregnancy, and it is recommended to go to the hospital to check the HCG to make it clear. The earliest time you can detect pregnancy after ovulation is about 14 days after ovulation with a test strip. Fertilized eggs are formed about 24 hours after intercourse, and the fertilized eggs begin to implant and secrete HCG 6 to 8 days after the formation of the fertilized eggs to promote the implantation of the fertilized eggs and the development of the embryo, and the earliest time for HCG to rise in the blood is 8 to 10 days after the formation of the fertilized eggs. As HCG in the blood rises, it can be detected in the urine with a pregnancy test stick 14 days after the formation of the fertilized egg, so the test paper on the 15th day of ovulation shows two marks, and the test strip is also considered to be pregnant, but of course false positives cannot be ruled out, and it is recommended that you can go to the hospital for blood tests to check HCG and progesterone, to make clear whether you are pregnant or not.