Does your period appear each month like clockwork, or is it more of a free spirit? An irregular cycle can be a nuisance, but once you’re ready to get pregnant, you might wonder if it’s more than that. Truth is, the regularity of your period is indeed related to fertility. 

Before you spiral, a wonky cycle doesn’t mean you are infertile, says Lauren M. Beasley, M.D., an obstetrician-gynecologist who practices with Centre Obstetrics and Gynecology in Raleigh, North Carolina. "It's most important to understand what is causing the patient to have irregular periods, such as a hormonal issue or a problem with the ovaries,” she explains. “I would want to initiate blood work and do a pelvic ultrasound to evaluate for those causes so we can prescribe treatment and ultimately help her to conceive.”

Deep breaths. Then read on to learn more about the link between irregular periods and fertility—and how to move forward.

First, What is a Normal Cycle Anyway?

A cycle is counted from the first day of bleeding of one menstrual period to the first day of bleeding of the next period, according to the American College of Obstetricians and Gynecologists (ACOG). So, in menstrual math, a regular cycle for most women lasts between 21 and 35 days, with the typical period going from two to seven days.  

What is Considered an Irregular Period?

Every person’s body is different, so there’s a lot of variability in what’s considered menstrually “regular.” Part of it is what’s regular for you, but there are also general guidelines around regularity (do we sound like a fiber commercial?). 

Overall, your period is considered irregular if it comes early, late, or not at all, or if it changes in length. Here’s more detail on that, according to ACOG:

• Your cycle is shorter or longer than usual. Consider whether the time from the first day of your last period up to the start of your next period is less than 21 days or more than 35 days, and if you are bleeding or spotting in between periods. 
• Your periods come 90 days apart, even for just one cycle. 
• Your period lasts longer than 7 days.

Beyond the timing, you’ll also want to pay attention to the strength of your flow. For example, if your bleeding is heavier than usual, or you’re soaking through more than one pad or tampon every one to two hours. Give your doctor a call if something is significantly different.

What Can Cause Irregular Periods?

Having an off cycle from time to time is no biggie; it’s normal. Many factors can contribute to occasional irregular periods, including hormonal imbalances, stress, weight changes, and some medications. But certain health conditions—including uncontrolled diabetes and eating disorders—can also make your period act up. It’s always best to talk to your doctor to rule things out and make sure you don’t need treatment.

Now, this is even more important if irregular periods are occurring regularly (say that five times fast). Persistent irregularities with your menstrual cycle can be due to an underlying medical condition that can affect your fertility. Some health issues your physician may screen you for:

Polycystic Ovary Syndrome (PCOS)
This disorder affects as many as 12% of women in the United States during their reproductive years. It’s a common cause of female infertility. 

With PCOS, women develop small, fluid-filled sacs (cysts) in the ovaries and have too much of the hormone androgen in their bodies. This can prevent or delay ovulation and cause irregular menstrual cycles, such as fewer periods or periods lasting longer than usual. 

Thyroid Disease

The butterfly gland that is your thyroid may be small, but it can have some pretty big effects. That’s because your thyroid is tied to many functions of the body—and it happens to control the timing of ovulation and your period. 

Thyroid disease can cause your periods to be heavy or light and happen more or less frequently. It can also disrupt ovulation, making it harder to conceive. If you do get pregnant, uncontrolled hyperthyroidism (when the body produces too much thyroid hormone) and hypothyroidism (when you don’t have enough of the hormone) can lead to health problems that can affect both you and the baby. 

Hyperprolactinemia

Having hyperprolactinemia means there is an abnormally high level of a protein hormone, called prolactin, in your blood. This messes with your reproductive system and can cause irregular or missed periods.

Premature Ovarian Insufficiency

This is when the ovaries stop working as they should before age 40.  They no longer make sufficient estrogen or release eggs regularly. (This does not mean you are in premature menopause, which is defined as not having a period at all for 12 straight months.)

Endometriosis

You have cells that usually grow inside the uterus. When those cells form outside of it, that’s endometriosis. This condition is marked by painful, heavy periods and can lead to fertility issues.

If it turns out you have any of these conditions, your ob/gyn will work with you to determine the best treatments.

How to Boost Your Chances of Getting Pregnant With Irregular Periods

Having irregular periods does not always translate to fertility issues. But it may be harder for you to get pregnant. Or it might take longer to conceive—after all, it’s more challenging to determine when you’re ovulating with erratic cycles.

It bears repeating that seeing your doctor is the first step in figuring out what’s going on. Once health issues are ruled out, you can help set yourself up for pregnancy success with these five strategies. 

1. Know what a regular cycle is for you. Start tracking your periods on a calendar; over several months, you may be able to identify patterns in your monthly cycles. Keep a record, and if your irregular periods persist, bring this info to your physician. You'll want to record:

• Start date and end date: How long did your period last? Is it shorter or longer than usual?
• Your flow: Is it lighter or heavier this month? 
• Pain: Did you experience any unusual pain or cramping?
• Other symptoms: Did you experience anything else, like mood swings, nausea, or headaches? Do they coincide with any other changes in your cycle? Using apps like Glow, Clue, and Flo can help make it easier to track and see patterns in your cycle. 

2. Watch for signs of ovulation. Start paying attention to your vaginal discharge. (C’mon! It’s…fun? Or at the least, informative.) When the discharge is stretchy, translucent, and resembles egg whites, it indicates that you're in the fertile zone. A sure fire way to know is an Ovulation Predictor Kit (OPK).
3. Maintain a healthy weight. Your weight is a critical factor when trying to conceive. Being either underweight or overweight can affect ovulation. How? A lack or excess of fat can cause an imbalance of hormones, leading to (you guessed it) irregular or missed periods. "If you are obese, even losing 5 to 10 pounds of body weight can significantly improve your chances of ovulation and conception,” Dr. Beasley advises.
4. Lower your stress. Ever heard of alpha-amylase? It’s a substance in the body that indicates stress. And research has shown that women with higher levels of the stuff are less likely to get pregnant. 
   
   Telling you to just chill out is easier said than done, but you can start by prioritizing the activities in your day that help you manage stress. This could be taking a walk or doing a moderate workout, finding some quiet time to read or take some deep breaths, and focusing on getting eight hours of restful sleep. 
5. Have more sex. Simply put, doing it regularly throughout the month may up your odds of conceiving. That’s because, with an irregular cycle, you may not know your exact fertile window. 

Bottom line: If you have irregular periods and have been unsuccessful trying to get pregnant, we recommend scheduling a conception planning discussion with your physician. They can guide you through personalized strategies and treatments to support your health—and that of your future pregnancy.