Does 3 week after intercourse can give reliable result? home pregnancy test?

The hormones of pregnancy can be detected as early as 3 weeks after exposure or when menses is delayed. Simple urine pregnancy tests are sometimes falsely negative early but will eventually be positive. The first morning urine is more concentrated & likely to be positive if pregnancy is present.

Conception occurs within day or so of the sex. It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully