Why No Period By Age 15?

Medically Reviewed by Poonam Sachdev on April 28, 2022

Girls usually get their first menstrual period when they’re 12 or 13. It’s a sign that your body is maturing, so that one day, if you want to, you should be able to have a baby.

By age 15, 98% of teens have started their periods. If you’re not one of them, make an appointment to talk to your doctor. They can ask you and a parent about your family history, daily activity level, and examine you to figure out the causes for your delay. The reasons may be nothing to worry about. Or they could be a sign that you have a health condition that you need to treat.

Family History

If your mom didn’t get their period until they were 15 or older, chances are that being a late bloomer runs in your family. That may especially be true if your aunts, grandmothers, and cousins also started menstruating only after they were well into high school. Girls tend to get their periods 2-3 years after their breasts start to develop and 6-12 months after they notice a mucus-like vaginal discharge in their underwear. All these milestones can happen later than average in some families, including yours. Still, your doctor may want to rule out other health problems.

Low Weight

If you weigh much less than normal, that can affect your hormone levels and prevent you from getting your period. If your weight is 10% less than what’s healthy for your height, it can keep your hormones from working right and actually stop your periods. This is why girls who have eating disorders like anorexia or bulimia may not start menstruating.

Extra Weight

If you’re obese, you may not have your first period at the usual time, either. To set a monthly menstrual cycle, your body needs a normal range of fat levels. Too much or too little body fat can lead to delayed periods. Obesity for someone 5 feet, 2 inches tall starts at 155 pounds.

Too Much Exercise

Pushing your body too hard physically also can make your first period come late. This can happen with ballet dancers, runners, or other athletes. Intense workouts burn lots of calories and can leave very little body fat. Mix that with competitive pressure, and they can postpone your period until you’re well into high school.

Too Much Stress

It can be hard on your body in many ways, and one possible effect is to delay your first period. This may happen if you’re stressed all the time, no matter if it comes from too much homework, family problems, intense sports training, or other issues.


Certain types of drugs can keep you from having a period, including those used to treat cancer, high blood pressure, allergies, and depression. If you’re taking any of them, your doctor may have explained that this could happen.

Physical Problems

Very rarely, you may not be able to have periods because of the shape or other issues with your vagina, ovaries, fallopian tubes, or uterus. You might have extra tissue that covers an opening, a blockage, or physical issues. Your doctor can find out if these problems may be the reason.

Other Health Issues

Conditions that may be behind your delayed periods include:

Show Sources


American College of Obstetricians and Gynecologists: “Menstruation in girls and adolescents: Using the menstrual cycle as a vital sign.”

Nemours Foundation: “All about menstruation.”

Stanford Children’s Health: “Amenorrhea in teens.”

Mayo Clinic: “Amenorrhea: Risk factors,” “Amenorrhea: Causes.”

National Institute of Child Health and Human Development: “What causes amenorrhea?” “Who is at risk of amenorrhea?”

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