Late ovulation.
Another reason is to take your time and wait for your period to be late.
In some cycles, ovulation shifts several days from the middle of the cycle. This is preceded by stress, overwork, climate change, infectious diseases, recent discontinuation of combined oral contraceptives, endocrine dysfunction, metabolic disorders, sudden weight loss or weight gain. With late ovulation, hCG reaches the test threshold values of 15–20 mIU/ml approximately on the 33rd day from the first day of the last menstruation. In this case, if a woman’s menstrual cycle lasts 28 days, the coloring of the second strip will occur no earlier than on the 5th day of the delay.