16 days late came on period should i be concern?

Maybe not, but...: A doctor can check to see if there is any worrisome medical issue, if a woman has mild menstrual-related symptoms. Many women have some variation of their periods or a missed period on occasion. Some women feel normal after a few days, but others do have repeated symptoms and follow-up with their doctors. A urine pregnancy test is very accurate if done correctly, and done after a missed period.