 [ Symptoms ] what are the signs and symptoms that a teen might be pregnant [ Disease ] missing one or more menstrual periods is the classic sign of pregnancy but this can be tricky for teenage girls whose periods are not yet regular it can also be tricky for girls whose cycles are off as a result of excessive dieting or exercise or low body fat from sports or anorexia the full list of pregnancy signs includes a missed menstrual period nausea or vomiting    called morning sickness  though it can happen throughout the day sudden intense aversion to certain foods especially meats or fatty fried foods sore nipples or breasts unusual fatigue frequent urination unusual mood swings of course a positive pregnancy test is another sign of pregnancy today is home pregnancy tests are generally considered accurate these simple kits can be bought over the counter in drugstores