if you are more than a week late starting your period you should take a pregnacy test. just to be sure. in my experience sex has never changed my cycle except when i was pregnant. one of my pregenacies i spotted for only one day which was not normal for me. so i took a test to rule that out but it turned out that was the reason why. hope this helps.
does sex change our period cycle? or could i be pregnant? . im not on birth control and have been having sex regularly. i had brown spotting and then the next morning bright red period (not the usual flow but still quite a bit) and its a week early. my breasts are tender and i feel extremely bloated. i took a pregnancy test a week before (was negative) but i reckon that was too early. i just want to know what i should do.