Menstruation

Also called: Menses, Menstrual period, Period

On this page

Summary

Menstruation, or period, is normal vaginal bleeding that occurs as part of a woman's monthly cycle. Every month, your body prepares for pregnancy. If no pregnancy occurs, the uterus, or womb, sheds its lining. The menstrual blood is partly blood and partly tissue from inside the uterus. It passes out of the body through the vagina.

Periods usually start between age 11 and 14 and continue until menopause at about age 51. They usually last from three to five days. Besides bleeding from the vagina, you may have

Abdominal or pelvic cramping pain
Lower back pain
Bloating and sore breasts
Food cravings
Mood swings and irritability
Headache and fatigue

Premenstrual syndrome, or PMS, is a group of symptoms that start before the period. It can include emotional and physical symptoms.

Consult your health care provider if you have big changes in your cycle. They may be signs of other problems that should be treated.

NIH: National Institute of Child Health and Human Development

Start Here

All about Menstruation (For Teens) (Nemours Foundation) Also in Spanish
Menstrual Cycle: What's Normal, What's Not (Mayo Foundation for Medical Education and Research)
Menstruation and Menstrual Problems (National Institute of Child Health and Human Development) Also in Spanish
Menstruation and the Menstrual Cycle (Department of Health and Human Services, Office on Women's Health) Also in Spanish
What Are Menstrual Irregularities? (National Institute of Child Health and Human Development) Also in Spanish

Latest News

No Such Thing as Menstrual Memory Fog (07/05/2017, HealthDay)
Concussion Can Spur Short-Term Change in Women's Periods (07/03/2017, HealthDay)

Diagnosis and Tests

Estrogen Test (American Association for Clinical Chemistry)
FSH (Follicle-Stimulating Hormone) Test (American Association for Clinical Chemistry)
How Do Health Care Providers Diagnose Menstrual Irregularities? (National Institute of Child Health and Human Development) Also in Spanish
Menstrual Cycle Problems (American Academy of Family Physicians) Also in Spanish
When You Visit Your Doctor: Irregular Menstrual Periods (Harvard Medical School)

Treatments and Therapies

Black Cohosh (National Center for Complementary and Integrative Health)
Chasteberry (National Center for Complementary and Integrative Health)
Endometrial Ablation (American College of Obstetricians and Gynecologists) - PDF
What Are the Common Treatments for Menstrual Irregularities? (National Institute of Child Health and Human Development) Also in Spanish
What Are the Treatments for Amenorrhea? (National Institute of Child Health and Human Development)

Related Issues

Adenomyosis (Mayo Foundation for Medical Education and Research)
Bleeding Disorders in Women (Centers for Disease Control and Prevention) Also in Spanish
Delaying Your Period with Birth Control Pills (Mayo Foundation for Medical Education and Research)
Hormone Replacement Therapy: Can It Cause Vaginal Bleeding? (Mayo Foundation for Medical Education and Research)
Noncontraceptive Benefits of Birth Control Pills (American Society for Reproductive Medicine) - PDF
Toxic Shock Syndrome (Mayo Foundation for Medical Education and Research)

Specifics

Amenorrhea (Hormone Health Network) - PDF
Amenorrhea (National Institute of Child Health and Human Development) Also in Spanish
Female Athlete Triad (American Academy of Family Physicians) Also in Spanish
Heavy Menstrual Bleeding (Menorrhagia) (Centers for Disease Control and Prevention)
Menorrhagia (Heavy Menstrual Bleeding) (Mayo Foundation for Medical Education and Research)
Mittelschmerz (Mayo Foundation for Medical Education and Research)
What Causes Menstrual Irregularities? (National Institute of Child Health and Human Development) Also in Spanish

Images

Menstrual Cycle (Department of Health and Human Services, Office on Women's Health)

Health Check Tools

Heavy Menstrual Bleeding (DSHI Systems)
Irregular Menstrual Periods (DSHI Systems)

Clinical Trials

ClinicalTrials.gov: Amenorrhea (National Institutes of Health)
ClinicalTrials.gov: Menstruation Disturbances (National Institutes of Health)

Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)

Reference Desk

Female Reproductive System (Nemours Foundation) Also in Spanish
Heavy Menstrual Bleeding (American College of Obstetricians and Gynecologists) - PDF
Menstrual Cycle (Merck & Co., Inc.)

Find an Expert

National Institute of Child Health and Human Development Also in Spanish
womenshealth.gov (Department of Health and Human Services, Office on Women's Health) Also in Spanish

Children

All about Menstruation (For Children) (Nemours Foundation) Also in Spanish
Five Things Girls Want to Know about Periods (Nemours Foundation)
Getting Your Period (Department of Health and Human Services, Office on Women's Health)
Menstrual Problems (For Parents) (Nemours Foundation) Also in Spanish
Pads and Tampons (Nemours Foundation) Also in Spanish
Talking to Your Child about Menstruation (Nemours Foundation) Also in Spanish
When Will I Get My Period? (For Kids) (Nemours Foundation) Also in Spanish

Teenagers

Coping with Common Period Problems (For Teens) (Nemours Foundation) Also in Spanish
Feeling Fresh (Nemours Foundation) Also in Spanish
Female Athlete Triad (Nemours Foundation) Also in Spanish
Irregular Periods (Nemours Foundation) Also in Spanish
Medical Uses of the Birth Control Pill (Children's Hospital Boston)
Menstrual Disorders (American Academy of Pediatrics) Also in Spanish
Problem Periods (Department of Health and Human Services, Office on Women's Health)
Toxic Shock Syndrome (For Teens) (Nemours Foundation) Also in Spanish
Using Your First Tampon (Children's Hospital Boston) Also in Spanish
Your First Period (American College of Obstetricians and Gynecologists) Also in Spanish
Your Menstrual Cycle (Department of Health and Human Services, Office on Women's Health)

Patient Handouts

Amenorrhea - primary (Medical Encyclopedia) Also in Spanish
Endometrial ablation (Medical Encyclopedia) Also in Spanish
Mittelschmerz (Medical Encyclopedia) Also in Spanish
Secondary amenorrhea (Medical Encyclopedia) Also in Spanish

Topic Image

MedlinePlus Email Updates

MEDICAL ENCYCLOPEDIA

National Institutes of Health

The primary NIH organization for research on Menstruation is the National Institute of Child Health and Human Development

Disclaimers

MedlinePlus links to health information from the National Institutes of Health and other federal government agencies. MedlinePlus also links to health information from non-government Web sites. See our disclaimer about external links and our quality guidelines.