How and when to use pregnancy tests? Couples who are not yet ready to have children use a variety of contraceptive methods. With all the care and the use of a variety of contraceptive methods, there may still be doubts about the possibility of pregnancy. Delay in the onset of period is the most important sign that women may become pregnant, but delay in period is due to normal physical and mental stress. Understanding the types of pregnancy tests and how to use them can help you get rid of these worries as quickly as possible.