text: why do some women skip a period even though they aren't pregnant? i took a pregnancy test and it was negative, but i still haven't started my period.  it isn't unusual for me to skip a period, but this is the first time i have skipped one while being sexually active.  i am not scared to be pregnant, i would actually like to be, but i just don't understand. there are many reasons why a period could be missed including diet, stress, pregnancy, infection, and hormonal balance.  as pregnancy blood tests are the most accurate, it is best to have one done 2 weeks after a missed period.  if it turns out to be negative, then your doctor can do further testing to see what's going on.