Do you get pregnant if you have sex 3 days after ovulation, i took a test the first day of having sex , and it said negative , ?

Wait, don't test yet: A urine pregnancy test done correctly gives a reliable result 3 weeks after sex (3 weeks after when conception might have happened) or 1 week after missing a period. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and therefore lead to a repeat test. If a woman has her normal regular period, then she is not pregnant, and a test is not needed.