Best time to take pregnancy tests

Dear Ask The Doctor: I recently took 2 pregnancy test and they both came out negative but I still havent got my period what does that mean?

Dear Cecilia: This is a very frequent question that we get asked about. For accurate results, pregnancy tests should be taken after you have crossed the estimated date of menstruation. Urine tests for pregnancy are most sensitive 2-3 weeks after conception. A blood pregnancy test is more sensitive and will be able to determine pregnancy even after 1 week of conception. Sometimes stress may also lead to a delayed period.