Menstruation

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

Eunice Kennedy Shriver National Institute of Child Health and Human Development

Start Here

• About Menstruation Eunice Kennedy Shriver National Institute of Child Health and Human Development
• All about Menstruation (For Teens) Nemours Foundation
• Menstrual Cycle Department of Health and Human Services, Office on Women’s Health
• Menstrual Cycle: What’s Normal, What’s Not Mayo Foundation for Medical Education and Research
• What Are Menstrual Irregularities? Eunice Kennedy Shriver National Institute of Child Health and Human Development

Patient Handouts

• Absent menstrual periods – secondary Medical Encyclopedia
• Amenorrhea – primary Medical Encyclopedia
• Endometrial ablation Medical Encyclopedia
• Mittelschmerz Medical Encyclopedia

Related Issues

• Adenomyosis Mayo Foundation for Medical Education and Research
• 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
• Period Problems: Fibroids, Endometriosis, and Other Issues National Institutes of Health
• Toxic Shock Syndrome Mayo Foundation for Medical Education and Research
• What Are Bleeding Disorders in Women? Centers for Disease Control and Prevention

Children

• All about Menstruation (For Children) Nemours Foundation
• 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
• Pads and Tampons Nemours Foundation
• Talking to Your Child about Menstruation Nemours Foundation
• When Will I Get My Period? (For Kids) Nemours Foundation

Specifics

• Amenorrhea Eunice Kennedy Shriver National Institute of Child Health and Human Development
• Female Athlete Triad American Academy of Family Physicians
• 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
• The Facts on Tampons — and How to Use Them Safely Food and Drug Administration
• What Causes Menstrual Irregularities? Eunice Kennedy Shriver National Institute of Child Health and Human Development

Diagnosis and Tests

• Anti-Müllerian Hormone Test National Library of Medicine
• Estrogen Levels Test National Library of Medicine
• Follicle-Stimulating Hormone (FSH) Levels Test National Library of Medicine
• How Do Health Care Providers Diagnose Menstrual Irregularities? Eunice Kennedy Shriver National Institute of Child Health and Human Development
• Menstrual Cycle Problems American Academy of Family Physicians
• 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
• What Are the Common Treatments for Menstrual Irregularities? Eunice Kennedy Shriver National Institute of Child Health and Human Development
• What Are the Treatments for Amenorrhea? Eunice Kennedy Shriver National Institute of Child Health and Human Development

Clinical Trials

• ClinicalTrials.gov: Amenorrhea National Institutes of Health
• ClinicalTrials.gov: Menstruation Disturbances National Institutes of Health

Find an Expert

• Department of Health and Human Services, Office on Women’s Health Department of Health and Human Services, Office on Women’s Health
• Eunice Kennedy Shriver National Institute of Child Health and Human Development Eunice Kennedy Shriver National Institute of Child Health and Human Development
• Find an Ob-Gyn American College of Obstetricians and Gynecologists

Teenagers

• Dr. Stacey Missmer on Painful Periods in Teens National Institutes of Health
• Feeling Fresh Nemours Foundation
• Female Athlete Triad Nemours Foundation
• Irregular Periods Nemours Foundation
• Menstrual Disorders in Teens American Academy of Pediatrics
• Period Products: Using Your First Tampon Boston Children’s Hospital
• PMS, Cramps, and Irregular Periods Nemours Foundation
• Problem Periods Department of Health and Human Services, Office on Women’s Health
• Toxic Shock Syndrome (For Teens) Nemours Foundation
• Your First Period American College of Obstetricians and Gynecologists
• Your Menstrual Cycle Department of Health and Human Services, Office on Women’s Health

Encyclopedia

• Endometrial biopsy Medical Encyclopedia
• Prolactin blood test Medical Encyclopedia

Reference Desk

• Female Reproductive System Nemours Foundation
• Menstrual Cycle Merck & Co., Inc.

Journal Articles

• Menstrual cycle