My period is 4 days late and i took a blood pregnancy test yesterday and it was negative. i also have taken urine tests and they were all negative. what is my chances of pregnancy? should i test again in a week? why is my period late?

TIMING: You haven't mentioned sexual intercourse, but since you are concerned, I'll assume that you are sexually active. If your periods are regular and you hd unprotected intercourse at mid-cycle (12-14 days prior to next expected period), you may be pregnant although it is not a certainty. A pregnancy test, which is reliable, will diagnose an early pregnancy before a careful pelvic examination, and tak