When to Worry About Missed or Irregular Periods

Common and Uncommon Causes You Should Know

no period pcos
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Polycystic ovary syndrome (PCOS) affects at least 10 percent of women of childbearing ages in the United States. PCOS is characterized by high levels of testosterone (all women have testosterone just like all men have estrogen) creating an imbalance of female sex hormones. In fact, PCOS is the most common cause of ovulatory infertility due to the hormone imbalance seen with the condition.

Having irregular periods and no periods (amenorrhea) is a definite symptom of PCOS. However, there are many things that can cause irregular periods, and PCOS is not the only one.

Possible Causes

The causes for irregular or absent periods are many and can involve either abnormalities within the uterus (like uterine fibroids) or external conditions that are sometime harder to pin down. PCOS is one of the conditions your doctor may explore, particularly if the menstrual irregularities are ongoing and persistent.

PCOS is typically diagnosed when a woman has at least two of three characteristic symptoms:

  • High androgen levels
  • Irregular menstrual cycles
  • Ovarian cysts

If you are a teenager who has only recently gotten her first period, or an older woman approaching ovarian failure (or menopause), irregular cycles are very common because your hormones are fluctuating. Menstrual irregularities may also be caused by a intrauterine device (IUD) or a recent change in an oral contraceptive.

If you exercise excessively, lose a significant amount of weight, or are under a lot of stress, your periods may be affected as well. Other medical conditions such as hypothyroidism (low thyroid function) and hyperthyroidism (excessive thyroid function) can also cause missed or absent periods. 

You should make an appointment to see a doctor if you have missed at least three menstrual periods in a row, or if you are 15 or older and have not yet menstruated.

Risks and Complications

An occasional missed period is normal. However, not having a regular period can increase your risk for endometrial cancer.

During a normal menstrual cycle, the endometrium is exposed to hormones, like estrogen, which cause the lining to proliferate and thicken. When ovulation does not occur, the lining is not shed and is exposed to much higher concentrations of estrogen, causing the endometrium to grow much thicker than normal. This is what contributes to the increased risk of cancer.

Keep in mind that this does not apply if you are taking a birth control pill, especially one designed to prevent you from getting your period more than once every few months. The pill keeps your hormone levels low and endometrial lining thin, dramatically reducing your risk of endometrial cancer.

Symptoms of endometrial cancer include pelvic pain, bleeding between periods, pain during intercourse, and a watery or blood-tinged discharge. As there are usually no other early warning signs, do not hesitate to see a doctor even if the symptoms are mild.


There are many different ways to treat irregular or absent periods in PCOS depending on your goals and health history. Generally, it's not good if you're not shedding your uterine lining each month. This can cause a build-up in the endometrial lining, increasing the risk for uterine cancer.

Some doctors recommend oral contraceptives to balance out hormones and create a regular cycle. Although not indicated for this reason, metformin can also help some women regulate their cycle.

Women with PCOS can experience regularity to their menstrual cycle through weight loss, changes to their eating, and exercise. In addition, the dietary supplement inositol, has been shown to be helpful to regulate periods and balance hormones in women with PCOS. 

If your periods suddenly become irregular, bring it to your doctor’s attention. Further diagnostic testing and/or medical intervention may become necessary.

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