Quick Answers
Most girls get their first period and experience menstrual cramps between the ages of 10 and 15. The average age is around 12. Cramping and other premenstrual symptoms can start 6 months to 2 years before getting a first period as a part of premenstrual syndrome (PMS).
When Do Most Girls Start Their Periods?
Menstruation starts during puberty. Puberty begins at different ages for everyone, and is influenced by factors like genetics, body weight, and overall health.
Here are some key points about when puberty and menstruation start:
- The average age for a first period is 12.
- Most girls get their periods between the ages of 10 and 15.
- Periods can start as early as age 8 or as late as age 15 and still be considered normal.
- Girls who are overweight, have a family history of early puberty, or who engage in intensive athletic training may start puberty on the early side.
- Delayed puberty can happen in girls with chronic illnesses, malnutrition, eating disorders, or underweight body types.
Age Ranges for First Periods
Here is a breakdown of the typical age ranges when girls get their first period:
- By age 10: 2.5% of girls
- By age 11: 10.5% of girls
- By age 12: 53.5% of girls
- By age 13: 89.3% of girls
- By age 14: 98.8% of girls
- By age 15: 99.9% of girls
As these numbers illustrate, less than 5% of girls start their periods before age 10 or after age 15. The largest jump happens between ages 11 and 12, which is when most girls get their first period.
When Do Girls Start Having PMS and Cramps?
Some girls experience premenstrual symptoms months or years before ever seeing their first period. This is known as premenstrual syndrome or PMS. Having PMS symptoms before a first period is sometimes called premenarcheal PMS.
PMS includes both physical and emotional symptoms that happen in the weeks leading up to a menstrual period. Cramps are one of the most common physical symptoms. Girls can start having PMS cramps 2 years before menarche (first period):
- Mild PMS may start around 6-12 months before the first period.
- More severe PMS can start up to 2 years before the onset of menstruation.
- PMS symptoms may come and go at first, then become more predictable and cyclic as hormones regulate.
- Cramps may start out mild and become more severe as estrogen and progesterone levels rise.
Keeping track of PMS symptoms from early on can help girls know what to expect with their periods. While PMS can be uncomfortable, it’s also a sign that the reproductive system is maturing in preparation for adulthood.
Signs of Early PMS and Cramps
Cramping and other premenstrual symptoms do not have to be extreme to signal oncoming periods. Here are some subtle signs of PMS cramps:
- Mild abdominal discomfort that comes and goes
- Feeling gassy or bloated around the abdomen
- Fatigue and feeling run down
- Changes in bowel habits like constipation or diarrhea
- Moodiness, irritability, anxiety
- Food cravings, especially for salt, chocolate, or sweets
- Feeling more emotional or tearful than usual
- Trouble focusing and concentrating
- Feeling stressed out or overwhelmed
- Mild headaches
- Breast tenderness or sensitivity
Learning to track subtle symptoms represents an important part of menstrual education for young girls. This way they know what to expect and can be prepared to manage symptoms when periods actually start.
Common Causes of Menstrual Cramps
Menstrual cramps happen when the uterine muscle contracts to shed the lining of the uterus. This process is triggered by hormone changes throughout the menstrual cycle.
Some common sources of period cramping include:
Prostaglandins
Hormones signal the uterus to release chemicals called prostaglandins that trigger uterine contractions. Higher levels can cause more intense cramping.
Bloody Flow
Restricted blood flow during periods can cause painful cramping. This may happen if clots block the cervical opening.
Adenomyosis
This condition causes the uterine lining to grow into the muscular wall of the uterus. This can lead to severe menstrual cramps.
Fibroids
Noncancerous tumors that grow in the uterus can make cramps worse by distorting the shape of the uterine cavity.
Endometriosis
When uterine tissue grows outside the uterus, it still bleeds each month. This causes swelling, irritation, and cramping.
Pelvic Inflammatory Disease
This infection of the female reproductive system can cause cramping pain during periods as infected tissue swells and sheds.
Adenomyoma
A benign tumor of the deepest muscle layer of the uterus is thought to contribute to some cases of primary dysmenorrhea.
Cervical Stenosis
A narrowing of the opening of the cervix can obstruct menstrual flow and cause painful contractions.
Endometrial Hyperplasia
Having an abnormally thick endometrial lining, which may happen with hormonal imbalance, can worsen menstrual cramps.
Intrauterine Devices
Some women experience increased cramping for the first 3-6 months after getting certain types of IUDs.
When to See a Doctor
Most of the time menstrual cramps are just a regular part of having periods. But severe or ongoing cramps can be a sign of an underlying gynecological condition that needs medical attention. See a doctor for cramps if:
- Cramps are so painful that normal activities are disrupted
- Pain medication provides little or no relief
- Cramps get worse over time instead of better
- Cramps are accompanied by heavy bleeding
- Cramps cause nausea, vomiting, or fainting
- Cramps are still severe 6-12 months after starting menstruation
- Cramps happen at unusual times in the cycle, like during ovulation
A gynecologist can perform exams and testing to check for any issues that may be contributing to severe menstrual cramps.
Typical Age Ranges for Puberty Development in Girls
Menstruation does not start until a sequence of puberty changes have happened. Here are the normal age ranges for different pubertal milestones:
| Puberty Stage | Average Age Range |
|---|---|
| Breast bud tissue develops | 8-13 years old |
| Pubic and underarm hair growth begins | 9-15 years old |
| Acceleration in growth | 10-14 years old |
| Menarche (first period) | 10-16 years old |
| Body odor increases | 9-17 years old |
As this timeline shows, breast development is usually the first visible sign of puberty. Periods typically start later, along with other changes like new hair growth and body odor.
Is It Possible to Get a Period Before Going Through Puberty?
It is extremely rare, but possible in exceptional circumstances for girls to menstruate before other puberty changes happen. This is called isolated menarche. Some examples include:
- Newborn vaginal bleeding – Some female infants have temporary bleeding from hormonal withdrawal right after birth.
- Premature adrenarche – Early secretion of androgens from the adrenal glands may trigger menstruation.
- Exogenous hormone exposure – Early use of products containing estrogens or androgens has triggered periods in a few young girls.
- Ovarian cysts – Cysts on the ovaries in young girls have sometimes led to atypical menstrual bleeding.
These cases are highly unusual, however. Doctors thoroughly evaluate any child who seems to get a true period without other puberty signs to check for precocious puberty or other abnormality.
Key Points About Menstrual Timing and Cramps in Young Girls
Here are some key takeaways about when most girls start menstruating and having cramps:
- Average age for first period is around 12 years old.
- Most girls get periods between 10 and 15 years old.
- Cramps may start 1-2 years before the first actual period.
- PMS symptoms often precede menarche as the body ramps up hormones.
- Menstrual cramps tend to become more severe once periods start.
- Cramps happening at normal times are usually just part of monthly cycles.
- Severe cramps may be a sign of an underlying medical condition.
Learning about what to expect around puberty and menstruation helps young girls be prepared. Tracking symptoms month to month allows differences from the norm to be identified.
FAQs
At what age do most girls start their periods?
Most girls get their first period between the ages of 10 and 15, with the average age being around 12 years old.
Is it normal to have cramps before your first period?
Yes, many girls start having mild cramps up to 2 years before getting their first period as part of premenstrual syndrome (PMS). These cramps are caused by hormonal cycles preparing for menstruation.
How early can PMS and cramping start?
PMS symptoms like cramping can start as early as 6-12 months before the onset of menstruation. Mild symptoms tend to come and go at first.
Should you see a doctor for period cramps?
See a gynecologist if period cramps are severe, persistent, or getting worse instead of better over the first 6-12 months after menarche. Unusually severe cramps may indicate an underlying problem.
Is it possible to get a period without going through puberty?
In extremely rare cases, girls might have isolated early menarche without other signs of puberty. This warrants medical evaluation to check for issues like hormone abnormalities.
The Bottom Line
Getting a first period is a key milestone in a girl’s life that means her body is maturing into adulthood. Doctors consider menstruation normal any time between age 8 and 15. Cramping often starts 1-2 years before the first actual period as part of PMS. While cramping can be uncomfortable, it shows the reproductive system is developing on track.
Severe or worsening cramps may signal a problem needing medical attention. But in general, experiencing cramps around puberty just means a girl’s body is preparing for this important transition. Tracking symptoms and cycles from early on helps girls learn what’s normal for their bodies.
