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Irregular Periods & Infertility: Possible Causes, Treatments & More

Are irregular periods causing your fertility issues? Learn what typically leads to cycle irregularity and how you can still conceive successfully.

July 7th, 2023 | 12 min. read

By Christina Dias, RN, BSN

Understanding the menstrual cycle is an essential part any fertility journey, especially for those planning for pregnancy. Knowing when you’re ovulating can help optimize your chances of conception. But what if you have irregular periods? Does cycle irregularity equal infertility? 

In this article:

Can irregular periods cause infertility?

The menstrual cycle is one of nature’s most widely misunderstood bodily functions, and irregular periods and infertility are topics that can be tough to talk about openly. However, when you know the facts and understand your options for conceiving with irregular cycles, your goals will feel much more manageable.

What's the connection between irregular periods and infertility? In short, it is simply more difficult to determine when you’re ovulating each month, or if you’re ovulating at all. When you're unsure about the timing of ovulation, trying to conceive becomes difficult.

So, what can cause such erratic behavior in menstrual cycles?

There are many factors that can contribute to cycle irregularity, making them longer or shorter, or causing your body to skip cycles altogether. We'll explore four of the most common reasons for irregular periods below.

The good news is that even with irregular periods, it’s very likely you can still get pregnant! However, it will likely make planning a pregnancy more challenging.

That’s where the fertility professionals come in. We’re here to help you understand why this might be happening, what you can do about it, and what your options are.

Before we dive in, let's briefly recap what happens during a typical menstrual cycle.

How does the menstrual cycle work? 

A typical or "regular" menstrual cycle lasts roughly 28 days. Fun fact: That's about the length of the moon’s monthly revolution around the earth. This hormonal cycle prepares the female reproductive organs for a possible pregnancy.

Around day 14 of your cycle, ovulation occurs. This is when hormonal spikes cause a mature egg to be released from the ovaries and pushed down the fallopian tube where the egg meets one of two fates:


Fertilization occurs when the egg meets and is fertilized by a sperm, resulting in pregnancy. Contrary to what you may have learned in health class, your chances of getting pregnant (even without known fertility issues or period irregularity) in any given cycle are much lower than you might expect - only around 20-25%.

Those chances of success also decrease with age.


When the egg doesn't meet or get successfully fertilized by a healthy sperm, the egg will be discarded through the process of menstruation, where the lining of the uterus is shed. More commonly referred to as a "period," this process causes bleeding for about four to eight days every month, signaling the end of the cycle.

Possible Causes of Irregular Periods

Navigating menstrual cycle irregularity when trying to conceive can be quite frustrating, often leaving hopeful parents wondering, "What's wrong with me?" Before we go on, it's important to acknowledge that in nearly all cases, there is nothing you've done to cause this. 

So, what causes irregular periods? There are four common conditions that can lead to cycle irregularity or anovulation (the technical term for the absence of ovulation). Let's talk about these four possible causes and how you can still get pregnant in spite of them. 

1. Polycystic Ovary Syndrome (PCOS)

One of the most common causes of irregular periods, affecting 1 out of every 10 people assigned female at birth, is called Polycystic Ovary Syndrome (PCOS)

PCOS is an imbalance of the hormones involved in the reproductive process. These imbalances can cause problems at various points in the ovulation cycle - affecting the development of an egg or even impacting when that egg is released into the uterus.

This, in turn, causes irregular or "missed" periods.

Unfortunately, there isn’t a definitive cause of PCOS, however, it often appears alongside an unusually high presence of androgens (testosterone) or excess insulin. Sometimes, an inflammation of the ovaries is to blame.

How to Get Pregnant with PCOS

Fortunately, symptoms of PCOS can be managed through lifestyle changes or with the aid of medications. Those who struggle with excess weight or have a family history of diabetes have a higher chance of developing PCOS.

Focusing on improving your overall health is one of the best lines of defense when it comes to this challenging, complex condition. Working with an experienced nutritionist can also be helpful as you learn to navigate PCOS. 

Birth control can help regulate your menstrual cycle, while other medications can enhance or block various hormone levels. If these steps do not work, in vitro fertilization (IVF) treatment has a very high success rate for those with PCOS.

Meet Mayra & Hervin

After unsuccessfully trying to conceive with irregular cycles and PCOS, a couple sought help from a fertility specialist to grow their family.

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2. Thyroid Imbalances

Do you have unexplained weight loss, increased appetite, difficulty sleeping and a perplexing amount of nervousness or anxiety? Or maybe you’re experiencing the opposite: weight gain, fatigue, and constipation? These symptoms might mean your thyroid (a tiny gland in your neck that regulates metabolism) isn’t working quite right. 

There are two ends of the spectrum when it comes to thyroid imbalances - your thyroid gland can either be producing too much or too little of the hormones your body needs to function normally.

When that little gland under-produces thyroid hormones, this is known as hypothyroidism. This often causes your body to slow down and feel sluggish. When it over-produces thyroid hormones (a condition known as hyperthyroidism), it sends your metabolism into overdrive.

How Thyroid Imbalances Impact Ovulation

Thyroid dysfunction can also impact your ability to get pregnant, since thyroid hormones send important signals to your ovaries. 

With hyperthyroidism (an overactive thyroid), the flooding of thyroid hormones causes an overall elevation of luteinizing hormone (LH), the same hormone that kicks off ovulation. But when LH is already elevated, the increase of LH during your ovulation cycle isn’t enough to signal ovulation to begin.

On the other hand, hypothyroidism (an underactive thyroid) causes low LH levels, which means there isn’t enough LH to cause ovulation to start. Either way, a thyroid disorder makes it more difficult for your body to ovulate. And if you can’t ovulate, you can’t get pregnant.

How to Get Pregnant with Thyroid Imbalances

Fortunately, there are very effective daily medications that either block thyroid hormone production (for hyperthyroid) or replace them with synthetic hormones (for hypothyroid).

Depending on the cause and severity of your thyroid disorder, there are also more permanent treatments, including thyroid surgery. Once thyroid levels are restored, your cycle should get back on track, too. But it will be important to monitor your thyroid throughout pregnancy and postpartum.

3. Endometriosis

Intense and unusual pain during the menstrual cycle, during intercourse, or general pain in your pelvic area can be due to a condition called endometriosis.

Endometriosis occurs when the endometrium (the tissue that lines the uterus) attaches and grows outside of the uterus. It can grow in the ovaries, fallopian tubes, outer surface of the uterus, or anywhere inside the lower abdominal region.

And it’s more common than you might estimated 11% of women of childbearing age have this condition. (Including all of these celebrities!) Although we don’t know why some people develop endometriosis, researchers have some hunches.

What causes endometriosis?

During your period, the lining of the uterus can get "backlogged" instead of shedding normally. In other cases, the immune system may not be strong enough to fight off leftover tissue before it attaches elsewhere. The disease also seems to run in families, suggesting a genetic link. Hormonal imbalances, too, are thought to possibly play a role.

How does endometriosis impact fertility?

These growths are typically benign, but can significantly impact your ability to get pregnant. For instance, if one of these abnormal tissue growths blocks your fallopian tubes or impacts the lining of the uterus, it could block your ability to ovulate or make it impossible for an embryo to successfully implant.

There are many reasons why this condition might endanger the path to pregnancy at various points within the process. While there is no cure for endometriosis, there are successful treatments.

How to Get Pregnant with Endometriosis

While endometriosis can be quite painful and complex, your chances of pregnancy are still quite high, as long as you receive proper treatment and support.

For those trying to conceive, temporarily halting ovulation by means of a gonadotropin-releasing hormone (GnRH) agonist can stop endometrial growth and allow for a healthy pregnancy once ovulation is resumed. In severe cases, surgery to remove the abnormal tissue can be an option.

Controlling the frequency of periods with hormonal birth control can offer pain management.

4. Diminished Ovarian Reserve (DOR)

One of the more serious conditions that affects the menstrual cycle and a person's ability to conceive is called Diminished Ovarian Reserve (DOR). This rare condition occurs when ovarian function is impaired in women under the age of 40.

Ovaries that don’t function well tend not to release eggs. It also often leads to a decrease in estrogen, which not only impacts your ability to become pregnant but it can cause other health problems, such as osteoporosis.

Symptoms of DOR mimic those of early menopause, such as:

  • Hot flashes
  • Decreased libido
  • Irritability

Sometimes this ovarian dysfunction can be traced back to chromosomal anomalies, autoimmune responses, or genetics, but more often than not, the cause is simply unknown.

Women with DOR sometimes have an ovulation cycle and release an egg, which can lead to pregnancy in about 5-10% of cases. But the frequency and predictability of ovulation is severely impacted, which makes planning a "natural" pregnancy highly difficult.

Unfortunately, there’s no cure or treatment proven to restore ovarian function.

How to Get Pregnant with Diminished Ovarian Reserve

Learning you may never be able to conceive due to diminished ovarian reserve can be extremely difficult news to receive. It will take time to process all of the information and grieve the vision you've held of being pregnant and bearing a child with your genetics.

However, if experiencing pregnancy is important to you, there are alternatives.

Many couples facing DOR expand their families by seeking out an egg donor and pursuing IVF treatment. Talk to your fertility clinic about your options. Be sure to have a strong support network in place as you explore the possibilities (a fertility counselor can be helpful too).

What can I do to help irregular periods?

A healthy body has the highest chance of getting pregnant, and this is the case whether or not you are struggling with irregular periods. However, in the case of an unpredictable menstrual cycle, improving your overall health and wellness can especially helpful for getting your periods back on schedule.

Nutrition & Movement

Those who struggle with excess weight or nutritional deficiencies have an increased risk for conditions that cause irregular cycles. With this in mind, we recommend eating a balanced, nutritious diet and starting an exercise routine that's right for your body. 

This is also a great opportunity to consult with a nutritionist, who can offer expert guidance and support around any nutrition and lifestyle modifications you're considering making.

Note: Be cautious and don't overdo it on the workouts. Extreme physical activity can also cause irregular cycles, as often seen in professional athletes. Make sure to take the time to build up your fitness appropriately.

Stress Reduction

Menstrual cycles are also highly impacted by emotional stress. It isn’t uncommon for stress to trigger your period or cause your body to skip a cycle. Finding ways to reduce stress - perhaps through techniques such as meditation, yoga, taking breaks from work, or even by prioritizing sleep - may help restore your cycle.

When facing irregular periods, consider your overall wellness, as it is an enormous factor in hormonal imbalances and focusing on things holistically often makes a real, positive impact.

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When should I call a doctor?

Start by tracking the number of days between the start of your periods.

If you consistently get your period in less than 21 days or more than 35 days apart, this is considered an irregular period.

Stress, exercise and other factors can sometimes impact your cycle in the short term, so some fluctuation can be normal and not a cause for major concern. However, you should reach out to a doctor if you’ve had irregular (or missed) periods for more than three months.

When the menstrual cycle is upset for a sustained period of time, there may be an underlying issue that needs attention. Unusual or deep pain is also a sign that it’s time to get checked out.

Should I see my OB/GYN or a fertility specialist?

You can always start by speaking with your OB/GYN about your concerns, or opt to go straight to a board-certified reproductive endocrinologist, who can monitor your overall health and test for various conditions that may be impacting your cycle and ability to conceive.

When you meet with your doctor, be sure to discuss your full medical history and any recent changes to your health, including any of the following:

  • Weight loss or gain
  • Unusual hair growth
  • Intensity and length of your periods
  • Changes to your sleep patterns
  • Prior pregnancies and surgeries
  • Mental health issues, such as depression or anxiety
  • Known reproductive problems in genetically-related family members

Getting Pregnant with Irregular Periods

If you're struggling with irregular periods while trying to conceive, stay hopeful! It's likely that you will still be able to get pregnant - it may simply require a little extra planning.

Feeling uncertain about when (or if) you're ovulating, experiencing cycle irregularity, or just wanting to rule out any fertility issues? It's never too early to reach out to a fertility specialist. By working with a reproductive endocrinologist, you can feel confident that you've left no stone unturned and have all the support you need on your journey to parenthood.

Christina Dias, RN, BSN

Christina Dias, RN, BSN joined the team at Illume Fertility in 2004. She currently serves as our Director of Nursing, overseeing our clinical care teams. She received her Bachelor of Science in Nursing from Sacred Heart University.

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