Can I detect pregnancy if my period is delayed by three days? Women\’s menstruation is a cyclical process. If you have sex and your menstrual period is delayed for three days, there is a possibility of pregnancy. To determine whether you are pregnant, you need to take a pregnancy test. So can I detect pregnancy if my period is delayed by three days? Below we will elaborate on it from four aspects. Pregnancy testing methods There are two methods for testing pregnancy, one is a pregnancy test paper, and the other is a pregnancy test.