Content Map Terms


Topic Overview

Your first menstrual period is called menarche (say "MEN-ar-kee"). It usually starts sometime between ages 11 and 14. But it can happen as early as age 9 or as late as 15. If you are a teenage girl, see your doctor if you have not started having periods by age 15. Menarche is a sign you are growing up and becoming a woman. Along with starting your period, your body is changing. You've begun to develop breasts, pubic hair, and underarm hair. And your hips have begun to widen. Menarche also means that if you have sex, you can get pregnant. You can even get pregnant in the month before your first period starts.

Starting your period

In the days before you start your period, you may feel tense or emotional. You may gain water weight and feel bloated. You may have pain (cramps) in your abdomen, back, or legs that lasts a few hours or more. Your breasts may be tender, and your face may break out.

When you start your period, you'll notice a spot of blood on your underwear or when you use the bathroom. The flow of blood from your vagina is usually light at first and may get heavier for a few days before tapering off. The blood may be a brownish colour at first and then turn brighter red. Your period will usually last 3 to 7 days each month.

Ask your mom, a doctor, or a woman you trust for advice on using feminine products for the bleeding, such as tampons or pads. A tampon fits inside your vagina and is good to use when swimming or doing other physical activities. A pad has adhesive strips that help it stick to your underwear. You'll need to change tampons and pads regularly. Having a period won't prevent you from doing any of the activities you normally do. And no one will be able to tell when you're having one.

If you have cramps with your period, regular exercise, a heating pad, a warm bath, and non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen may help. Be safe with medicines. Read and follow all instructions on the label. If you are younger than 18, do not take aspirin. Aspirin raises the risk of Reye syndrome, a disease that affects the brain and liver. If these treatments don't help, talk to your doctor about prescription medicines.

For more information on managing menstrual cramps, see:

Your menstrual cycle

Your period is part of your menstrual cycle, the time from the first day of your period to the first day of the next period. A normal menstrual cycle for teenagers can be anywhere from 21 days to 45 days.

For the first year or two, your cycle may not be regular and you may not have a period sometimes. If you are underweight because of dieting or exercise, have a lot of stress in your life, or are overweight, your periods may be hard to predict.

Keep a calendar, and mark the day you start your period each month. This can help you predict when you'll have your next period and is also useful when you talk with your doctor.

Your menstrual cycle makes it possible for you to get pregnant. Sometime around the middle of each cycle, you will ovulate, which means one of your ovaries will release an egg. You may have a slight discharge from your vagina or some spotting of blood when you ovulate.

You are most likely to get pregnant if you have sexual intercourse on the day of ovulation or on any of the five days before it. For more information, see:

Pregnancy facts

You should assume you can get pregnant any time of the month. The timing of ovulation is different for everyone, especially those who have periods that don't start at the same time every month.

Don't rely on your friends' advice about how and when you can get pregnant. Talk to a health professional—your doctor, school nurse, or nurse practitioner—and parents, if possible, for reliable information about preventing pregnancy and sexually transmitted infections.

The following is a list of myths about sex and pregnancy:

Myths about sex and pregnancy



You can't get pregnant the first time you have sex.

Getting pregnant has nothing to do with how many times you have sex. If you are near the time of ovulation when you have sexual intercourse, you can get pregnant.

You can't get pregnant if you're very young.

If you have started your periods, you can get pregnant, even if your body is not mature enough to handle the stress of pregnancy. Girls age 10 or 11, or even younger, have become pregnant. You can also get pregnant in the month before you start your first period.

You can't get pregnant if you have sex standing up.

Position has nothing to do with getting pregnant. The egg and sperm can move no matter what position your body is in.

You can't get pregnant if you have sex during your period.

Although the chance of getting pregnant at this time is less for most women, if you have short cycles (less than 28 days) or irregular periods, you may be able to get pregnant if you have sex during your period.

You can't get pregnant if you have sex in a hot tub.

If you have unprotected sex, you can get pregnant, regardless of where you are.


Other Works Consulted

  • American Academy of Pediatrics, American College of Obstetricians and Gynecologists (2006, reaffirmed 2009). Menstruation in girls and adolescents: Using the menstrual cycle as a vital sign. Pediatrics, 118(5): 2245–2250.


Current as of:
February 11, 2021

Author: Healthwise Staff
Medical Review:
Sarah Marshall MD - Family Medicine
Anne C. Poinier MD - Internal Medicine
Martin J. Gabica MD - Family Medicine
Kathleen Romito MD - Family Medicine
Femi Olatunbosun MB, FRCSC - Obstetrics and Gynecology
Rebecca Sue Uranga