Why Do Some Women Get Their Period Twice a Month?

The causes of frequent periods

Getting frequent periods, and even two periods in one month, is at the very least annoying, and it could be a sign of an underlying medical issue. However, it could also just be how your body functions or a stage of life you're going through. Regardless, if you're having more frequent periods than you're used to, or you get them more frequently than most, it's worth a conversation with your doctor to figure out why.

The 28-day cycle that's thought of as "standard" is really just an average, not the rule. It's considered normal for a menstrual cycle to range anywhere from 21 to about 35 days. While most women have a regular cycle they can rely on, some have irregular periods for their entire lives.

Your period frequency, how many days it lasts, and how much you bleed is influenced by your body's current hormone levels. Hormones fluctuate, especially when you're near the beginning or end of your reproductive years, have certain medical conditions, or even make certain lifestyle changes. All of these things can make you have more frequent periods or give you an occasional early period. Factors that could be at play include:

  • Age
  • Endometriosis
  • Thyroid disease
  • Uterine polyps or fibroids
  • Skipping or discontinuing birth control
  • Pelvic inflammatory disease
  • Cancer
  • Weight gain
  • Lifestyle changes

Age

Age plays a major role in your menstrual cycle, including period frequency, duration, and heaviness. Your teen years are a prime time for cycle irregularities, as are your 40s and early 50s.

Causes of Irregular Menstrual Cycles in Teenagers

Verywell / Ellen Lindner

Teen Years

The average age to start menstruating is 12, but again, that's not a rule. The first period can come anywhere between 8 and 16. The first couple of years can be irregular due to constantly shifting hormones, which may increase the likelihood of periods that are close together.

While it's usually not a cause for concern, you shouldn't just assume that frequent or irregular periods are normal—especially if your cycle suddenly changes, going from regular to irregular or, say, from 28 days to 14 days. Be sure to let your doctor know what's going on so they can check for medical causes.

If there's no underlying condition causing frequent or irregular periods, the most common treatment is oral contraceptives (birth control pills).

 HORMONAL CHANGES AVERAGE AGE AGE RANGE
First period  12 8-16
Perimenopause  41-43 Late 30s-Mid 40s
Menopause 51 Late 40s-Early 50s
Early menopause -- 40-45
Premature menopause -- Under 40

Perimenopause

Perimenopause is when you go through what used to be called "the change," and declining estrogen levels can make your cycle irregular and your periods more (or less) frequent, as well as shorter or longer and lighter or heavier.

A lot of times, people refer to this transitional time as menopause, but menopause doesn't officially begin until you've gone a full year without a period. The average age for menopause is in the late 40s and early 50s, but it's possible to arrive there earlier or later.

You can be in perimenopause for about eight to 10 years before reaching menopause. Some women also have early (before age 45) or premature (before age 40) menopause. Changes in period frequency may be a sign that you're entering one of these phases.

Abnormal uterine bleeding has a lot of potential causes, though. Don't assume it's perimenopause-related, and see your doctor for proper diagnosis and treatment. If your frequent periods are due to perimenopause, you may be able to regulate them with birth control pills, patches, or rings.

Bleeding After Menopause

Any vaginal bleeding after menopause is considered abnormal and may be a sign of serious disease, including endometrial cancer. Call your doctor right away if you're postmenopausal and have any vaginal bleeding or abnormal discharge.

Endometriosis

Endometriosis is a medical condition in which the tissue that lines the inside of the uterus (called the endometrium) grows on the outside of that organ. The two primary symptoms of endometriosis are painful periods, excessive bleeding, and short menstrual cycles—which can mean having two periods a month.

The reason for these extra and more severe periods is that your body has more endometrium to shed because of the overgrowth outside of the uterus. You might also have bleeding and pain when you ovulate because the tissue can adhere to the ovaries and form cysts.

Ovulation typically happens between 11 and 21 days after the start of your menstrual cycle (the first day of your most recent period), depending on the length of your cycle. If you have a short cycle and bleed during ovulation, you may experience very frequent bleeding.

However, the bleeding that comes with ovulation should be just a bit of spotting. If it's heavy enough to fill even a pantyliner, call your doctor.

Painful, frequent periods don't always indicate endometriosis. Other symptoms of endometriosis include:

  • Menstrual cramps that aren't relieved by over-the-counter anti-inflammatory drugs
  • Nausea and vomiting
  • Excessive gas
  • Diarrhea
  • Chronic pelvic pain
  • Fatigue
  • Headaches or migraines
  • Leg pain
  • Pain during vaginal penetration
  • Painful bowel movements
  • Difficulty getting pregnant

Endometriosis is often managed with low-dose birth control pills or other hormone therapies. In some cases, doctors recommend surgery to remove the problem tissues or to remove the uterus itself.

Thyroid Disease

Your thyroid gland and the hormones it produces are important for regulating your menstrual cycle. Having either too much or too little thyroid hormone can impact your periods in multiple ways, but having too little—called hypothyroidism—is the more likely one to give you frequent periods.

Hypothyroidism can also make your periods especially heavy. You may need to change your pad, tampon, or cup every hour or double up (such as wearing a tampon and pad.) They may also last longer than a week. Other symptoms of hypothyroidism include:

  • Feeling especially cold
  • Constipation
  • Muscle weakness
  • Unexplained weight gain
  • Joint or muscle pain
  • Fatigue
  • Especially dry skin
  • Thinning hair
  • Depression or sadness
  • Puffy face
  • Decrease in sweating

Hypothyroidism is typically treated with synthetic thyroid hormones.

Too Much Thyroid Hormone

Having too much thyroid hormone is called hyperthyroidism. It's most often associated with less frequent or missed periods, or even the absence of periods.

Uterine Polyps or Fibroids

Uterine polyps, also called endometrial polyps, are soft growths in the endometrium. They can range from sesame-seed sized to larger than a golf ball and are not usually cancerous. Uterine polyps become more common with age and are rare in anyone under 20. You may develop one or many.

Uterine fibroids are another type of non-cancerous growth on the uterus, but they develop from the muscle tissue rather than the endometrium. They may be inside or outside of the uterus and, as with polyps, you can have one or several.

Both polyps and fibroids can cause menstrual irregularities, including more frequent periods, longer and heavier periods, and bleeding between periods. They can also interfere with your fertility and cause miscarriage. Other symptoms of uterine polyps include:

  • Post-menopausal bleeding or spotting
  • Bleeding after vaginal penetration
  • Infertility

Other symptoms of uterine fibroids include:

  • Bloating and distension
  • Frequent urination and inability to empty your bladder
  • Pain during vaginal penetration
  • Pain in the lower back
  • Constipation
  • Vaginal discharge

Treatments for polyps and fibroids ranges from hormonal therapies and symptom management to surgical removal of the growths or, in more serious cases, hysterectomy.

Other Names for Fibroids

  • Leiomyomas
  • Myomas
  • Uterine myomas
  • Fibromas

Skipping or Discontinuing Birth Control

Birth control pills suppress your normal menstrual cycle with hormones that prevent ovulation. The pills usually come in a three-week supply followed by a week of placebos (pills that don't contain hormones), and the lack of hormones during the placebo week is what makes you have a period.

When you go off of the pill, or even miss just a pill or two, your body may react like it does during the placebo week and start shedding the uterine lining. This can happen even if it hasn't been very long since your last period. A similar process happens if you make a mistake with a birth control patch or ring.

The proper way to resume your birth control after missing one or more doses varies by type, so be sure to read the information that comes with your contraceptive or ask your doctor or pharmacist what to do. And don't forget that you may need a backup method of contraception or emergency contraception to avoid an unintended pregnancy.

Pelvic Inflammatory Disease

Sometimes, normal vaginal bacteria or sexually transmitted infections, especially chlamydia and gonorrhea, can move from the vagina up to the uterus and cause pelvic inflammatory disease (PID). The risk of this is higher during your period and when your cervix is open, such as if you've recently had a baby, miscarriage, abortion, or IUD placement.

PID can cause irregular menstrual cycles or spotting and cramping between periods. Other symptoms include:

  • Pain or tenderness in the lower abdomen
  • Yellow or green vaginal discharge with a strange odor
  • Fever or chills
  • Nausea and vomiting
  • Burning with urination
  • Pain during vaginal penetration

Repeated bouts of PID can cause scarring on the fallopian tubes that can lead to chronic pelvic pain, ectopic pregnancy, and infertility. Antibiotics can clear up the infection but can't get rid of the damage it does to your reproductive organs, so it's important to get prompt treatment.

Warning: Anemia

Heavy or prolonged menstrual bleeding can lead to iron-deficiency anemia, which can cause fatigue and weakness. If you experience these symptoms during or after a heavy period, see your doctor to have your iron levels checked.

Cancer

Cancers of the reproductive organs can disrupt your hormones and menstrual cycle. While most menstrual irregularities aren't a sign of cancer, they can be. This makes it important for you to see your doctor any time your menstrual cycle changes without a clear reason, such as missing a few birth control pills.

While cervical and ovarian cancers are tied to menstrual irregularities, they're generally associated with long and heavy periods and less associated with more frequent periods. Uterine cancer can cause you to have periods more often.

Uterine Cancer

Two types of cancer are possible in your uterus:

  • Endometrial cancer: By far the most common, tumors develop in the uterine lining.
  • Uterine sarcoma: This extremely rare cancer develops in the wall of the uterus.

Either type of cancer can cause more frequent periods that may be very long and heavy, especially if you're over 40. They can also cause bleeding between periods and spotting or bleeding after menopause. Other symptoms include:

  • Pain or cramping in the lower abdomen/pelvis
  • Unexplained weight loss
  • After menopause, a thin, clear or white vaginal discharge

Treatments for uterine cancer depend on the type you have and how healthy you are. They may include:

Weight Gain and Obesity

Weight gain and obesity can affect the frequency of your period in a couple of ways. Rapid weight gain can throw your cycle off because it affects the hypothalamus, which is a part of your brain that regulates hormones. That can lead to hormonal fluctuations that may include more- or less-frequent periods.

Obesity has a complex relationship with menstruation. High levels of fat, also called adipose tissue, can upset the balance of sex hormones and lead to excess estrogen, which can make you have short menstrual cycles and more periods. It also can cause heavier bleeding, more cramps, and more prolonged pain during your period. These problems are most pronounced when the adipose tissue is concentrated around the abdomen.

Losing weight, or maintaining a healthy weight, can help keep your menstrual cycle regular. If you need help losing weight, talk to your doctor about what options you have.

Weight and PCOS

Being overweight may increase your risk of polycystic ovary syndrome (PCOS), which can prevent ovulation and cause infrequent periods that tend to be longer than usual.

Lifestyle Changes

Changes in your day-to-day routine may have an impact on your menstrual cycle and lead to having more periods, including:

  • High stress levels
  • Extensive travel
  • Increase in exercise levels
  • Lack of sleep

All of these factors put the body under stress, which throws off the hypothalamus and leads to the release of excess cortisol (a stress hormone). All that cortisol causes changes to your hormone regulation that can lead to irregular menstrual cycles and either more or fewer periods.

Typically, a return to your normal routine will get your cycle back on track. If it keeps being irregular, talk to your doctor.

Call Your Doctor If:

  • Your period becomes irregular
  • You don't have a period for three months
  • Your periods are less than 21 days apart
  • Your periods are more than 35 days apart
  • You have a period that lasts more than 7 days
  • You have an unusually heavy or painful period
  • You bleed between periods
  • You bleed at all after menopause

A Word From Verywell

With so many factors influencing your menstrual cycle, it's likely that you'll experience some menstrual irregularities during your lifetime. You shouldn't assume the worst every time things are off by a few days, but you should let your doctor know about any menstrual irregularities you have. Catching a problem early can prevent it from having a much bigger impact on your health and your life.

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  1. Cleveland Clinic. Normal menstruation. Updated August 25, 2019.

  2. TeensHealth from Nemours. Irregular periods.

  3. National Institutes of Health, Eunice Kennedy Shriver National Institute of Child Health and Human Development. What are the common treatments for menstrual irregularities? Updated January 31, 2017.

  4. The American College of Obstetricians and Gynecologists. Perimenopausal bleeding and bleeding after menopause. Updated October 2020.

  5. Cleveland Clinic. Menopause, perimenopause and postmenopause. Updated December 24, 2019.

  6. Delamater L, Santoro N. Management of the perimenopauseClin Obstet Gynecol. 2018;61(3):419-432. doi:10.1097/GRF.0000000000000389

  7. American Cancer Society. Signs and symptoms of endometrial cancer. Updated March 27, 2019.

  8. National Women's Health Network. How does endometriosis affect my menstrual cycle? Updated March 8, 2018.

  9. American Pregnancy Association. What is ovulation? Updated April 24, 2020.

  10. Endometriosis Foundation. Endometriosis symptoms: Abnormal periods. Updated March 9, 2021.

  11. Ajmani NS, Sarbhai V, Yadav N, Paul M, Ahmad A, Ajmani AK. Role of thyroid dysfunction in patients with menstrual disorders in tertiary care center of walled city of DelhiJ Obstet Gynaecol India. 2016;66(2):115-119. doi:10.1007/s13224-014-0650-0

  12. U.S. Department of Health & Human Services, Office on Women's Health. Thyroid disease. Updated April 1, 2019.

  13. Cleveland Clinic. Uterine polyps. September 28, 2018.

  14. University of Michigan Medical School, Michigan Medicine: Von Voigtlander Women's Hospital. Uterine fibroids & abnormal bleeding.

  15. Cleveland Clinic. Uterine fibroids. August 24, 2020.

  16. University of Iowa Hospitals & Clinics. Birth control pill fact sheet. Updated November 2015.

  17. Planned Parenthood. Will missing my birth control mess up my period? Updated April 21, 2020.

  18. University of Michigan, Michigan Medicine. Symptoms of pelvic infection. Updated July 17, 2020.

  19. Cleveland Clinic. Abnormal menstruation (periods). August 25, 2019.

  20. Centers for Disease Control and Prevention. Pelvic Inflammatory Disease (PID) - CDC Fact Sheet. Updated January 25, 2017.

  21. Cleveland Clinic. Pelvic inflammatory disease (PID). Updated November 23, 2020.

  22. Centers for Disease Control and Prevention. Heavy menstrual bleeding. Updated December 20, 2017.

  23. National Institutes of Health, U.S. National Library of Medicine: MedlinePlus. Cervical cancer. February 26, 2021.

  24. Centers for Disease Control and Prevention. Ovarian cancer: What are the symptoms? Updated March 8, 2021.

  25. Cleveland Clinic. Uterine cancer. Updated January 20, 2021.

  26. Cleveland Clinic: Healthessentials. Can stress cause you to skip a period? Updated September 18, 2020.

  27. Kafaei-Atrian M, Mohebbi-Dehnavi Z, Sayadi L, Asghari-Jafarabadi M, Karimian-Taheri Z, Afshar M. The relationship between the duration of menstrual bleeding and obesity-related anthropometric indices in studentsJ Educ Health Promot. 2019;8:81. Published 2019 Apr 24. doi:10.4103/jehp.jehp_24_18

  28. Planned Parenthood. Does being overweight cause your period to be irregular? If so, how many missed periods could you have? Updated June 29, 2020.

  29. University of Pennsylvania Medical School: PennMedicine. Irregular periods: Why is my period late? Updated November 2, 2020.

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