Irregular periods explained: 8 big reasons your period's gone MIA

Everything you ever wanted to know about irregular periods — it doesn't always mean you're pregnant

Sometimes the only thing worse than getting your period is not getting your period. Those of us cursed with irregular periods know all to well what it's like to worry about when the next monthly cycle will come.

The frustration of an irregular period is real, and because a woman's body and hormonal system can be so sensitive, it's a fairly common condition. But just because it's common, doesn't mean that dealing with a menstrual flow that decides to show up whenever it wants isn't a huge pain.

Furthermore, a regular cycle is a huge signifier that your reproductive health is in working order, or that you're not pregnant — so beyond frustration, irregular periods are sometimes cause to worry. The good news is that once you've ruled out any potential medical issues, you can attempt to figure out the underlying trigger messing with your cycle.
A normal period versus an irregular period

"The monthly menstrual cycle typically occurs every 28 days, is controlled by various hormones and is a key function of the female body," says Dr. Sherry Ross, MD, OB/GYN and Women’s Health Expert at Providence Saint John’s Health Center in Santa Monica, California. "Your 'period' begins around 11-12 years of age, lasts 2-7 days and continues until your reach menopause, which occurs around 51 years old."

Dr. Ross continues, "Ovulation is an important part of the menstrual cycle and occurs around Day 14 when an ovarian follicle produces an egg, which can be fertilized by sperm. The egg is only available to be fertilized for 24 hours before it disintegrates. Once you have ovulated, your period will occur, which is typically 14 days later."

The amount of blood shed during a period varies from woman to woman. Some women routinely have heavier periods (losing up to 12 teaspoons of blood each month) while others may experience a period that's almost non-existent (losing as little as four teaspoons of blood).

If you've been menstruating for a while, your body will get into a period flow, which is why an irregular period is usually defined as any type of bleeding that's abnormal when compared to your last few menstrual cycles. It can include everything from a late period to early bleeding, and scant bleeding to extremely heaving bleeding. For many women, this can even mean an absent period (amenorrhea) or two periods in one month (metrorrhagia). Two periods in one month, or a period every two weeks, are thought to be caused by an imbalance in estrogen and progesterone and may require a trip to the doctor since this can induce anemia.

And if you're not prone to PMS, you can also consider a period irregular if you experience heavy cramping and bloating or headaches.
The many causes of irregular periods

Every woman will experience an irregular period from time-to-time, and though, in most cases, they aren't dangerous, it's important to figure out what's causing the irregularity. Here are a few common reasons you may be experiencing an abnormal flow. 

1. Stress 

Stress is the most common cause of irregular periods. Cortisol, the stress hormone, has a direct impact on how much estrogen and progesterone, two sex hormones, gets produced by the body. If you have too much cortisol in your bloodstream, the time and flow of your cycle could change. Dr. Carolyn C. Thompson, MD, FACOG, board-certified OB/GYN, says, "In order for a woman to have a normal menstrual cycle (in which she does not become pregnant), the hypothalamus in the brain must send hormonal signals to the pituitary gland, which must in turn signal the ovary, which then signals the uterus. The hypothalamus is adjacent to areas in the brain that influence emotion; neurotransmitters form these centers can shut down the signals to the hypothalamus and therefore stop the outgoing signals from the hypothalamus. Evolutionarily speaking, this makes sense — if a woman is under a great deal of stress, either physical or emotional, it is likely not an ideal time for a pregnancy, so the system shuts down."

2. Diet

Another common reason for a late or missing period is the food you eat and, more specifically, the weight you're carrying. If you're eating a diet that's rich in unhealthy carbs or if you've gained weight, your body will produce varying levels of certain hormones, shifting when you ovulate. The same goes for women as they lose weight. "In order for a woman to maintain a regular cycle, her body fat percentage needs to be at least 17-22 percent. This is again related to the evolutionary idea that a state of starvation is not conducive to maintaining a healthy pregnancy, so, again, the system shuts down," says Dr. Thompson.

3. Exercise 

Our bodies need energy to menstruate. If you're burning too much of your energy in the gym, there will be nothing left for your body to use during that time of the month. "The list of what causes irregular periods is longer than you think, but we know excessive exercising, sudden weight changes and being underweight can offset your hormone levels. One of these hormones is called Leptin and is produced in fatty tissue. Excessive exercising and drastic weight changes can decrease the body fat, causing this and other hormones to drop, contributing to irregular periods," says Dr. Ross.
 

4. Birth control pills

 It can take several months for your body to get used to the dose of hormones birth control pills deliver. On top of that, Dr. Ross explains, "One of the side effects of a low dose birth control pill is a light or non-existent period. For many, this is a welcomed side effect! When some women stop taking the pill, their periods may take one to three months to return to normal. The birth control pill doesn’t cause you to have amenorrhea. It may be once you are off the pill you may find you have an underlying hormonal problem that was masked by taking the birth control pill. If this is the case, you should alert your healthcare provider."

5. Polycystic ovary syndrome (PCOS)

 Affecting up to 5 million women in the U.S., this condition causes cysts to form on the ovaries, interfering with regular ovulation. Other symptoms of the condition include hair growth, weight gain, dandruff and infertility. While Dr. Thompson reminds us that PCOS is far more complicated than a missed period, she says that anovulation (absence of ovulation) is one of the hallmarks of the disorder. "If the egg is not released from the ovary, the progesterone withdrawal never occurs, so the uterine lining never sheds. The lining can build under the continuous influence of estrogen until it can no longer sustain itself, then a heavy and lengthy period can result," Dr. Thompson explains.

6. Menopause

 As with pregnancy, this time of life happens when hormone levels in the body begin to shift. Irregular periods can start as early as 10 years before menopause sets in (usually when a woman is in her late 40s or early 50s). According to Dr. Thompson, the reason that menopause can cause irregular periods is quite simple: "Menopause is the cessation of ovulation — all of the eggs have been used up." She adds, "As a woman approaches menopause, ovulation becomes sporadic, so the period can be sporadic as well."

7. Taking medications

 If you were recently sick and had to take prescription or over-the-counter medication, your period may show up a day or two late. That's largely because most medications interfere with the way your body produces estrogen and progesterone. Dr. Ross agrees, saying, "There are many medications that can affect your menstrual cycle. They include aspirin, Coumadin, ibuprofen and naproxen, birth control pills, Depo-Provera, Nexplanon or Implanon, Mirena IUD and thyroid medication."

8. Pregnancy

 "Pregnancy obviously stops the menstrual period; a period occurs when a prepared endometrium (uterine lining) fails to implant a fertilized egg. There is no such thing as a woman continuing to have periods during a pregnancy. Bleeding in pregnancy is never normal, and usually needs to be investigated," explains Dr. Thompson. If there's a chance you may be pregnant, speak with your doctor.

Treating irregular periods

"Unfortunately, not having a period is not how our bodies are meant to function from a hormonal perspective. When you get a period each month, this suggests your hormones are balanced," says Dr. Ross. "There is something magical when your body is in sync hormonally. When your periods are monthly, a lot of women feel more emotionally and physically balanced." She advises, "If you are not getting your period for more than six months, it’s important you visit your healthcare provider for a general workup. If you are having irregular periods, there are treatment options available for you. Hormonal options, such as the birth control pill or progesterone, are typically used to regulate and balance out your periods. You can try acupressure or a homeopathic alternative to try to regulate your menstrual cycle, but hormones tend to work best."

And as the rule goes with most health concerns, if something doesn't feel right, don't hesitate to ask your doctor for help. Dr. Ross says, "Always better safe than sorry, especially with irregular periods."

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