When to Worry About Missed or Irregular Periods

Polycystic ovary syndrome (PCOS) affects 3% to 10% percent of women of childbearing ages. 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.

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.

A woman talking to her a doctor
Tetra Image / Getty Images

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 sometimes 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 your 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 an 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 of 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.

This causes the endometrium to grow much thicker than normal. It 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 of 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 to regulate their cycle.

People 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 people 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.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Wolf WM, Wattick RA, Kinkade ON, Olfert MD. Geographical prevalence of polycystic ovary syndrome as determined by region and race/ethnicity. Int J Environ Res Public Health. 2018;15(11). doi:10.3390/ijerph15112589

  2. The Practice Committee of the American Society for Reproductive Medicine. Current evaluation of amenorrhea. Fertil Steril. 2004;82 Suppl 1:S33-9. doi:10.1016/j.fertnstert.2004.07.001

  3. The Rotterdam ESHRE/ASRM‐sponsored PCOS consensus workshop group. Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome (PCOS). Hum Reprod. 2004;19(1):41-7. doi:10.1093/humrep/deh098

  4. Parazzini F, La vecchia C, Bocciolone L, Franceschi S. The epidemiology of endometrial cancer. Gynecol Oncol. 1991;41(1):1-16. doi:10.1016/0090-8258(91)90246-2

  5. Naderpoor N, Shorakae S, De courten B, Misso ML, Moran LJ, Teede HJ. Metformin and lifestyle modification in polycystic ovary syndrome: systematic review and meta-analysis. Hum Reprod Update. 2015;21(5):560-74. doi:10.1093/humupd/dmv025

  6. Morley LC, Tang T, Yasmin E, Norman RJ, Balen AH. Insulin-sensitising drugs (metformin, rosiglitazone, pioglitazone, D-chiro-inositol) for women with polycystic ovary syndrome, oligo amenorrhoea and subfertility. Cochrane Database Syst Rev. 2017;11:CD003053. doi:10.1002/14651858.CD003053