If the normal menstrual cycle is regular, the ovulation period usually occurs about 14 days before the next menstrual period. If there is sexual intercourse around the days before and after the ovulation period, the chance of pregnancy is relatively high. Generally, two weeks after sexual intercourse, or when the next menstrual period is due or delayed, early pregnancy test strips can be used to test. If the early pregnancy test strip shows two red lines, it is clear that pregnancy has occurred. If the test shows one red line, it indicates that there is no pregnancy. If one red line is darker and the other is lighter, it can be retested after a week.

Early pregnancy test strips can usually detect pregnancy one week or more after the menstrual period is delayed. For women who have had sexual intercourse without contraception, if the menstrual cycle is regular, generally, pregnancy can be considered 10 days or so after the expected date of the menstrual period. Early pregnancy symptoms usually appear about six weeks after the menstrual period stops, with symptoms such as dizziness, constant drowsiness, nausea, vomiting, aversion to oil, etc. From about the 8th week of pregnancy, symptoms such as frequent urination and breast enlargement may occur. When the early pregnancy test strip shows a positive result, it is recommended to go to a regular hospital department of obstetrics and gynecology for further diagnosis.

The appearance of a blank strip on the ovulation test strip is a major indication of a failed test. The reasons for the blank strip on the ovulation test strip are on the one hand due to incorrect operation steps during the testing process, and on the other hand, it is considered that the quality of the test strip is not good, expired, or invalid. If a quality-assured ovulation test strip is used to test the ovulation period, and the operation steps are correct, there will not be a blank result regardless of the time range of the entire menstrual cycle.

The result of ovulation test strips is negative before the uterus is fully developed during the ovulation monitoring. As the egg matures, the ovulation test strips gradually turn from faintly positive to positive and strongly positive. After the ovulation test strips show strongly positive, the ovulation period occurs within 24 to 48 hours. After the ovulation period, the ovulation test strips quickly change from strongly positive to faintly positive, and then to negative, but it is not easy to appear white strips.