Irregular Periods and Polycystic Ovary Syndrome (PCOS): What's the Connection?

Irregular Periods and Polycystic Ovary Syndrome (PCOS): What's the Connection?

When it comes to your period, it all comes down to hormones. If your periods are irregular, or you experience abnormal bleeding, you may have an imbalance in the ratio of hormones such as testosterone, estrogen, and progesterone.

One of the most common hormonal imbalances that affect your period is called polycystic ovary syndrome (PCOS). Up to 12% of girls and women in their reproductive years have PCOS. Although PCOS is not a life-threatening condition, it can cause discomfort and complications, including infertility and diabetes.

Our expert OB/GYNs, Daniel McDyer, MD, FACOG, and Julian Stephen Suhrer, MD, diagnose and treat PCOS at our two Florida Woman Care of Jacksonville offices in Jacksonville, Florida. If you’re wondering why you can never predict when — or if — your period’s going to come, PCOS may be the reason. Here’s why.

How a “normal” period behaves

When your hormones are in balance, you have your period on a regular basis. Although the exact timetable varies by individual, most girls and women menstruate for 3-7 days. Each period starts anywhere from 21-35 days after the last. The average cycle is 28 days. 

Your cycle is regulated by the hormones your body produces at different times. A normal period has four phases:

Menses phase

You count your cycle from the first day you shed blood, otherwise known as Day One. The menses phase usually lasts from 3-5 days.

Follicular phase

Starting around day 6 and lasting until day 14, your body produces more of the hormone estrogen. Because you’ve shed your uterine lining, it’s time to build it up again in case you get pregnant.

You also produce another hormone called follicle-stimulating hormone (FSH) so that some of the follicles in your ovaries start to grow. From about days 10-14, at least one of those follicles produces a mature egg.


A hormone called luteinizing hormone (LH) triggers the follicle to release its egg. 

Luteal phase

From about days 15-28, your egg travels through your fallopian tube toward your uterus. Now you produce the hormone progesterone to help prepare the uterine lining for a pregnancy. If you don’t get pregnant, progesterone drops and you begin menstruating on Day One.

How PCOS affects your periods

If you have PCOS, your body doesn’t produce the hormones you need to take you from one phase to the next in your menstrual cycle. Instead, you have higher-than-normal levels of androgens, such as testosterone, that throw your cycle off kilter.

When androgens are too high, your ovaries don’t trigger the follicles to develop and release an egg. Women without PCOS usually have 12 menstrual cycles per year. If you have PCOS, however, the excess androgen disrupts this process and, instead, you may only have 6-8 periods per year, or even fewer. 

PCOS affects more than your period

The excessive androgens that your body produces do more than disrupt your cycle and make it harder to get pregnant. Because hormones affect your metabolism, PCOS may lead to weight gain. 

PCOS is also associated with insulin resistance, which can lead to prediabetes or even diabetes. In fact, more than 50% of women with PCOS have type 2 diabetes by the time they’re 40.

You may also notice that you have more hair on your face than most other women. You might also have more body hair. Other signs of PCOS are losing scalp hair and being prone to acne. 

Because you don’t produce eggs and menstruate regularly, it may be harder than normal to get pregnant and stay pregnant. If you have PCOS and want to become pregnant, you should start working with a specialist immediately to increase your chances.

Treating PCOS and irregular periods

If PCOS is behind your irregular periods, we design a treatment plan that’s targeted to your severity of disease, age, and reproductive goals. Lifestyle changes that may shift your hormonal balance include:

If you want to become pregnant, we may recommend medications that help you ovulate. If you don’t want to become pregnant right away, you could benefit from hormonal contraception, which can help regulate your period. Diabetes medications, such as metformin, may also be helpful.

Irregular periods are a sign that your hormones are out of balance. Find out why your periods are irregular and get the individualized treatment you need by contacting our supportive team today at our Jacksonville, Florida, location nearest you. Or, use our online appointment form.

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