Determining whether a girl is pregnant can be difficult, particularly if the girl is young or not yet regular in her menstrual cycles. The symptoms of early pregnancy are startlingly similar to those typically associated with the days before menstruation, meaning that it's easy to confuse a pregnancy with an impending period. Further, since younger women and girls are less likely to be regular in their menstrual periods, they may not know that they've missed a period until quite some time has passed, and they may be less attuned to their bodies and new sensations than older women. A logical approach, culminating in physician confirmation of a suspected pregnancy, helps tremendously.
Use a calendar to keep track of menstrual cycles by marking each day of menstrual flow. This way, if cycles are regular, it will be easier to determine whether a menstrual period is missing.
Mark ovulation dates on the calendar, if possible. Some girls can feel themselves ovulate. In their book "What to Expect When You're Expecting," Heidi Murkoff and Sharon Mazel point out that ovulation typically takes place 12 to 14 days before the start of the menstrual period. Girls who can feel ovulation should mark it on their calendar as a sign of impending menstruation.
Anticipate the expected arrival of a period. A girl who menstruates regularly should know approximately when her period is due to arrive. If it does not show up within a few days of the expected date, and if she has had sexual intercourse since her last period--protected or not--this is a sign of potential pregnancy.
If an expected period does not arrive, check for pregnancy using a home pregnancy test. These tests can detect the pregnancy hormone, hCG, in urine. While tests claim to be accurate from the first day of a missed period, the American Pregnancy Association says that tests are more accurate when taken at least one day after an expected and absent menstrual period.
Visit an appropriate health-care professional for confirmation of the pregnancy. This step is important whether a home pregnancy test shows a positive result or not, if a regularly menstruating girl has missed a period by more than a week. Most doctors' offices are equipped with blood tests that are more sensitive and reliable than home urine tests, so they can confirm pregnancies even when home tests aren't showing positive results.
Things You'll Need
Home pregnancy test
If a home pregnancy test taken a few days after a missed period turns out negative, it’s worthwhile to wait at least another week before testing again, as this gives hCG plenty of time to build up in the girl’s body. If, after a week, the expected period is still absent, retesting with a home pregnancy test is more likely to give a positive result than tests taken earlier in the pregnancy.
If a girl suspects she's pregnant, it's best for her to behave as though she is until receiving confirmation one way or another. Avoiding drugs, unnecessary medication, alcohol and caffeine goes a long way toward a healthy baby.