My husband & i had unprotected sex 3 weeks ago. i took multiple pregnancy tests & all are negative. last test i took was 6 days ago. could i still be pregnant? ive been having headaches, mood swings. period has been irregular due to breastfeeding?

A urine pregnancy test should be positive 2 or more weeks after unprotected exposure if conception occurred. The tests are more often falsely negative early in the process, they are seldom falsely positive. The symptoms cited are non-specific. You can re-test as often as you wish.

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.