Hello and thank you for visiting our site. In women who are having unprotected intercourse, and who have a delay in their period along with other symptoms of pregnancy (lower abdominal pain and breast tenderness), then by all means they might be pregnant. You absolutely need to check a pregnancy test. If the test is positive, then you need immediate evaluation given the pain in order to rule out an ectopic pregnancy (a pregnancy in the fallopian tube). If the test is negative, then these symptoms are related to your cycle - they are common symptoms that occur after ovulation but before your period. I hope that this helps and good luck! Dr. Tim