Why Do Some Women Get Their Period Twice a Month?

Getting your period twice in a month can be annoying, inconvenient, and confusing. It can be a sign of an underlying medical problem, but it could also happen because of a habit change, a phase of life, or simply because of the way your body works.

This article explains the most common reasons you might have a period more often than expected:

• Age
• Endometriosis
• Thyroid disease
• Uterine polyps or fibroids
• Skipping or discontinuing birth control
• Pelvic inflammatory disease
• Cancer
• Weight gain
• Lifestyle changes, such as getting less sleep

It also reviews other signs and symptoms of conditions that can cause irregular cycles and how they are treated.

While this article is a good place to start when working to solve the mystery of your frequent periods, it's important to see your healthcare provider—especially if this persists.

The "Normal" Menstrual Cycle

Ovulation is the release of an egg that's ready for fertilization. Ovulation typically happens 11 to 21 days after you start bleeding from a period (the start of menstruation).

Getting your period every 28 days is considered "normal." But that's an average, not the rule. Normal menstrual cycles actually last anywhere from 21 to about 35 days.

Some woman naturally have very short cycles and some even bleed during ovulation. However, ovulation-related bleeding should be just a bit of spotting.

While most women have a regular cycle they can rely on, some have irregular periods at certain times or even for their entire lives because of factors we delve into next. This may mean more frequent periods or occasionally early periods.

Age

Your period frequency, how many days it lasts, and how much you bleed are influenced by your body's current hormone levels. These fluctuate throughout your life.

This is especially true during the teen years, when cycles are often irregular. Cycles may normalize in one's 20s or 30s only to once again become irregular in their 40s and early 50s—the lead up and transition to menopause.

Teen Years

The average age to start menstruating is 12, but again, that's not a rule. The first period can come anywhere between ages 8 and 16.

Periods in the first few years may be irregular, as hormones are constantly shifting. That may increase the chances that periods come close together.

While it's usually not a cause for concern, a healthcare provider should do an evaluation to be sure.

If there's no underlying condition causing frequent or irregular periods, doctors may prescribe oral contraceptives (birth control pills) to regulate your cycle.

Perimenopause

Perimenopause is the period of time in which you are transitioning to, but have not yet reached, menopause (the point at which you have gone 12 months without a period).

Estrogen levels drop during this time, which can make your cycle irregular and your periods more (or less) frequent. The blood flow may also be shorter or longer and lighter or heavier.

Most women experience this phase in their late 30s and mid-40s and stay there 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.

If period changes are due to perimenopause, you may be able to regulate them with birth control pills, patches, or rings.

Call your healthcare provider 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 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 since it is overgrown. You might also have bleeding and pain when you ovulate because the tissue can adhere to the ovaries and form cysts.

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, healthcare providers recommend either surgery to remove the problematic tissues or a hysterectomy, which is surgery to take out the uterus itself.

Thyroid Disease

Your thyroid gland and the hormones it produces are important for regulating your menstrual cycle. Where having too much thyroid hormone (hyperthyroidism) can cause missed or absent periods, having too little—called hypothyroidism—is more likely to make periods more frequent.

Hypothyroidism can also make your periods especially heavy. You may need to change your pad, tampon, or cup every hour or double up your protection (such as wearing a tampon and pad). Periods 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
• Dry skin
• Thinning hair
• Depression or sadness
• Puffy face
• Decrease in sweating

Hypothyroidism is typically treated with synthetic thyroid hormones.

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. These growths 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. You may also hear them called leiomyomas, myomas, or fibromas.

Fibroids may be inside or outside 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 swelling of the abdominal area
• 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 range from symptom management and hormonal therapies to surgical removal of the growths or, in more serious cases, hysterectomy.

Pelvic Inflammatory Disease

Sometimes, normal vaginal bacteria or sexually transmitted infections—especially chlamydia and gonorrhea—can move from the vagina up to the uterus, fallopian tubes, or ovaries. When it does, the infection is called 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 any damage it may do to your reproductive organs, so it's important to get prompt treatment.

Cancer

While most menstrual irregularities aren't a sign of cancer, they can be.

Cancers of the reproductive organs, including the uterus, cervix, and ovaries, can disrupt your hormones and menstrual cycle.

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: Tumors develop in the uterine lining (by far the most common type)
• Uterine sarcoma: Cancer develops in the wall of the uterus (extremely rare)

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
• Thin, clear or white vaginal discharge (after menopause)

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

• Chemotherapy
• Radiation
• Hormone therapy
• Immunotherapy
• Medications that stop cancer cells from multiplying
• Surgery, most often hysterectomy
  

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). 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, causing a period. This can happen even if it hasn't been very long since your last one.

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.

Weight Gain and Obesity

Rapid weight gain can throw your cycle off because it affects the hypothalamus, a part of your brain that regulates hormones. That can lead to hormonal fluctuations that may cause periods to be more (or less) frequent.

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 more estrogen than you need. Too much estrogen 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 severe when fat is mostly around the belly.

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 your options.

Lifestyle Changes

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

• Stressful events
• 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. This 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.

When to Call Your Doctor

While some of the causes of frequent periods aren't harmful and don't need to be treated, you shouldn't just assume that's true in your case.

Call your doctor if:

• Your period becomes irregular, especially if it's sudden or without an obvious cause (like a missed birth control pill)
• Your periods are less than 21 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

It's helpful to come with a record of when recent periods started and stopped. Also track symptoms such as pain and heavier blood flow, fatigue, weight gain, or fever. This will help your healthcare provider narrow down the possible causes.

If they find that there is a medical cause for your frequent periods, treatment can be started. And if there's no medical cause, you can be reassured that you are healthy and get advice on how to get your cycle back on track.

Summary

Shorter menstrual cycles are not necessarily a sign that something is wrong. They may actually be the norm for some people. However, if your period suddenly changes without an obvious reason like menopause, talk to your doctor. 

There are many reasons your period might be coming more often than usual. Natural hormone fluctuations can cause this, as can lifestyle factors like being overweight or stressed. But having your period twice in one month could also be a sign of a medical condition that needs treatment.

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.

Try not to assume the worst every time things are off by a few days, but be sure you make your doctor aware of any menstrual irregularities you have. Catching a problem early can prevent it from having a much bigger impact on your health and your life.