I did sex 3 months ago i had regular period after sex till june but in july i miss my period .is any change of getting pregnent?

Not possible, but...: If a woman has a regular normal period after sex, then she is not pregnant. If she cannot be certain that her bleeding was a normal period, then she could possibly be pregnant. A urine pregnancy test (available in stores everywhere) done 3 weeks after the last time she had sex will give the answer. Be sure to read the instructions and do the test correctly.