When after intercourse would a home pregnancy test be effective?

10-14 days: The pregnancy test can be effective 10-14 days after intercourse. I suggest to wait for the regular menstruation. If the menstruation fail to start, do one pregnancy test. If the test is negative, wait another 1-2 weeks for the menstruation to come. If not, repeat the pregnancy test. If the test is again negative and menstruation is absent, there may be other causes for the missing menstruation.