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• Summary
• Start Here
• Diagnosis and Tests
• Treatments and Therapies

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• Related Issues
• Specifics

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• Clinical Trials
• Journal Articles

Resources

• Reference Desk
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• Children
• Teenagers
• Patient Handouts

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

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

Diagnosis and Tests

• Anti-Müllerian Hormone Test (National Library of Medicine) Also in Spanish
• Estrogen Levels Test (National Library of Medicine) Also in Spanish
• Follicle-Stimulating Hormone (FSH) Levels Test (National Library of Medicine) Also in Spanish
• How Do Health Care Providers Diagnose Menstrual Irregularities? (Eunice Kennedy Shriver National Institute of Child Health and Human Development) Also in Spanish

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) Also in Spanish
• What Are the Treatments for Amenorrhea? (Eunice Kennedy Shriver National Institute of Child Health and Human Development) Also in Spanish

Related Issues

• Adenomyosis (Mayo Foundation for Medical Education and Research) Also in Spanish
• Delaying Your Period with Hormonal Birth Control (Mayo Foundation for Medical Education and Research) Also in Spanish
• Menopause Hormone Therapy: Does It Cause Vaginal Bleeding? (Mayo Foundation for Medical Education and Research) Also in Spanish
• Noncontraceptive Benefits of Birth Control Pills (American Society for Reproductive Medicine)
• Period Problems: Fibroids, Endometriosis, and Other Issues (National Institutes of Health) Also in Spanish
• Toxic Shock Syndrome (Mayo Foundation for Medical Education and Research)

Specifics

• About Heavy Menstrual Bleeding (Centers for Disease Control and Prevention) Also in Spanish
• Amenorrhea (Eunice Kennedy Shriver National Institute of Child Health and Human Development) Also in Spanish
• Female Athlete Triad (American Academy of Family Physicians) Also in Spanish
• Menorrhagia (Heavy Menstrual Bleeding) (Mayo Foundation for Medical Education and Research) Also in Spanish
• Mittelschmerz (Mayo Foundation for Medical Education and Research) Also in Spanish
• The Facts on Tampons -- and How to Use Them Safely (Food and Drug Administration) Also in Spanish
• What Causes Menstrual Irregularities? (Eunice Kennedy Shriver National Institute of Child Health and Human Development) Also in Spanish

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)

• Article: Period poverty: a scoping review.
• Article: The effect of education on adolescents' knowledge of menstrual characteristics and...
• Article: Adolescents, menstruation, and physical activity: insights from a global scoping review.
• Menstruation -- see more articles

Reference Desk

• Female Reproductive System (Nemours Foundation) Also in Spanish

Find an Expert

• Department of Health and Human Services, Office on Women's Health Also in Spanish
• Eunice Kennedy Shriver National Institute of Child Health and Human Development Also in Spanish
• How to Find Find an Ob-Gyn (American College of Obstetricians and Gynecologists)

Children

• All about Periods (For Kids) (Nemours Foundation) Also in Spanish
• Five Things to Know About Periods (Nemours Foundation) Also in Spanish
• Pads and Tampons (Nemours Foundation) Also in Spanish
• PMS, Cramps, and Irregular Periods (For Parents) (Nemours Foundation) Also in Spanish
• Talking to Your Child About Periods (Nemours Foundation) Also in Spanish
• When Will I Get My Period? (For Kids) (Nemours Foundation) Also in Spanish

Teenagers

• Can I Get Pregnant Right After My Period Ends? (Nemours Foundation) Also in Spanish
• Can Masturbation Affect Periods? (Nemours Foundation) Also in Spanish
• Could I Get Pregnant if I've Never Had My Period? (Nemours Foundation) Also in Spanish
• Feeling Fresh (Nemours Foundation) Also in Spanish
• Irregular Periods (Nemours Foundation) Also in Spanish
• Period Products: Using Your First Tampon (Boston Children's Hospital) Also in Spanish
• PMS, Cramps, and Irregular Periods (For Teens) (Nemours Foundation) Also in Spanish
• Toxic Shock Syndrome (For Teens) (Nemours Foundation) Also in Spanish
• Your First Period (American College of Obstetricians and Gynecologists)

Patient Handouts

• Absent menstrual periods - primary (Medical Encyclopedia) Also in Spanish
• Absent menstrual periods - secondary (Medical Encyclopedia) Also in Spanish
• Endometrial ablation (Medical Encyclopedia) Also in Spanish
• Mittelschmerz (Medical Encyclopedia) Also in Spanish