Why Women With PCOS Have Irregular Periods

People with polycystic ovary syndrome (PCOS) often have irregular or absent menstrual cycles, due to hormonal imbalances. Sometimes irregular periods are a sign of infertility in PCOS. Fortunately, menstrual irregularity and infertility can be treated.

This article discusses how PCOS influences menstrual cycles and how to regulate it.

How PCOS Affects the Menstrual Cycle

Every month, a follicle matures and gets released by the ovaries to be fertilized. This is not the case in PCOS. When ovulation doesn't occur, it can cause ovulatory infertility. PCOS is the most common cause of ovulatory infertility.

Among its effects, PCOS causes females to have higher levels of androgens like testosterone, and high levels of luteinizing hormone (a hormone that helps support ovulation and pregnancy).

Here's how PCOS affects your menstrual cycle:

  • High levels of circulating androgens, such as testosterone, interfere with the menstrual cycle and can prevent ovulation.
  • Because of the hormonal imbalance of PCOS, the follicle doesn't mature or get released.
  • Instead of being released, the follicle (often miscalled a cyst) stays in the ovaries, where it can be seen on an ultrasound.
  • Without ovulation and the hormonal events that lead up to it, the uterus does not have the stimulation it needs to shed its lining (have a regular period).

This effect can produce different symptoms. Some people who have PCOS can have regular periods every 28 days, others have periods every 30 to 40 days, and still, others don't have periods at all.

While menstrual irregularity is a normal symptom of PCOS, it needs to be treated, especially if you are getting fewer than eight or nine periods each year.

Not having a regular period can affect your fertility, and can also increase your risk of developing endometrial cancer.

Woman laying in bed with period cramps
skaman306 / Getty Images

Best Ways to Regulate Your Cycle

There are some ways that you can control your period and ensure that your uterus sheds its lining regularly.

  • Losing Weight: If you are overweight, even losing 5% to 10% of your total body weight can improve menstrual regularity and fertility in PCOS.
  • Taking the Birth Control Pill: Birth control medications can regulate your hormone levels and lower your testosterone level to give you a more consistent period.
  • Taking Medications Such as Glucophage or Provera: Both of these medications can cause women with PCOS to have a period. Provera is used cyclically to induce shedding of the uterine lining to protect it from becoming cancerous. Glucophage (Metformin) may be used off-label for weight loss and promoting ovulation, though some data does not support its use.
  • Taking a Combination of Myo and d-Chiro Inositol: Inositol has been shown to reduce testosterone and aid in regulating menstrual cycles, as well as promoting ovulation in women with PCOS. These supplements are not FDA-approved as a treatment for PCOS.

You should speak with your healthcare provider before starting to take any medication or supplement. Due to your specific health condition, you may not be a good candidate to take a particular medication, or your healthcare provider may recommend a certain regimen.

Ask your healthcare provider any questions you have about other alternatives, or why they have recommended the suggested treatment.

3 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. Welt CK, Carmina E. Clinical review: Lifecycle of polycystic ovary syndrome (PCOS): from in utero to menopauseJ Clin Endocrinol Metab. 2013;98(12):4629–4638. doi:10.1210/jc.2013-2375

  2. Harris HR, Titus LJ, Cramer DW, Terry KL. Long and irregular menstrual cycles, polycystic ovary syndrome, and ovarian cancer risk in a population-based case-control studyInt J Cancer. 2017;140(2):285–291. doi:10.1002/ijc.30441

  3. Teede H, Deeks A, Moran L. Polycystic ovary syndrome: a complex condition with psychological, reproductive and metabolic manifestations that impacts on health across the lifespanBMC Med. 2010;8:41. doi:10.1186/1741-7015-8-41

By Nicole Galan, RN
Nicole Galan, RN, is a registered nurse and the author of "The Everything Fertility Book."