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If I Have Irregular Periods, Will I Have Trouble Getting Pregnant?


Updated August 15, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Woman looking at a calendar to predict her period

If you don't know when your period is coming, it may be harder to know when you're ovulating.

Vstock LLC / Getty Images

Irregular periods can make getting pregnant more difficult, but they don't necessarily mean you won't be able to get pregnant on your own.

The cause of your irregular periods, how irregular your periods are, and whether or not you can time sex for pregnancy accurately will all factor into the chances of your getting pregnant.

What Are Irregular Periods?

An irregular period is defined as menstrual cycle that is either shorter than 21 days, or longer than 36 days. It may also be defined as cycles that vary significantly from month to month, even though they are within the normal time frames. For example, if one month your cycle is 23 days, and another it's 35, and then another it's 30, you might say you have irregular cycles.

It's actually normal for women to experience irregular cycles occasionally. Stress or illness can cause a delay in ovulation or menstruation, causing your cycle to be longer, and sometimes shorter, than usual. One or two periods a year that are "off" isn't something to be worried about.

However, if your cycles are often irregular, or you've got quite a long time between menstrual cycles, you should see your doctor for an evaluation.

What Causes Irregular Periods?

As mentioned above, the cause behind irregular cycles has a lot to do with your chances of getting pregnant. Sometimes, irregular periods are a sign of anovulation. Anovulatory cycles are menstrual cycles where ovulation doesn't take place. If you're not ovulating, you can't get pregnant.

Irregular periods may be a sign of polycystic ovarian syndrome (PCOS). Depending on whether you ovulate on your own or not, you may be able to get pregnant by yourself with PCOS.

Sometimes, irregular cycles point to a more subtle hormonal imbalance, but you may still be ovulating month to month. Just that your ovulation day varies greatly. If you're ovulating, you may be able to get pregnant without the help of fertility drugs.

Another possible cause of irregular periods -- being overweight, or underweight, can cause a disruption in your menstrual cycles. Both being overweight, and underweight, can also cause anovulation. Extreme exercise and extreme dieting are more potential causes of irregular cycles.

In this case, losing weight may be enough to regulate your cycles again, increasing the chances of getting pregnant naturally. If extreme dieting is the problem, changing your diet to a more balanced plan, and even gaining some weight if you're underweight, can help regulate your cycles.

When to Talk to Your Doctor About Irregular Cycles

If you have irregular periods, the best thing to do is see your gynecologist. Even if you weren't trying to get pregnant, it's a good idea to get checked out.

Usually, the recommendation is that you try to get pregnant for one year (or six months if you're age 35 of older), and then, if you don't conceive, to see a doctor. T

However, this doesn't apply if there are signs of a problem. Irregular cycles is a risk factor for infertility.

Your doctor can run some simple blood tests to see if you are ovulating or not. If your blood work indicates that you are ovulating, and you're not over 35, you might want to keep trying to get pregnant on your own for a bit longer.

Catching the Egg When Your Cycles Are Irregular

If you are ovulating, but irregularly, you'll need to make a special effort at detecting your most fertile time.

There are many ways to predict ovulation, and you might need to use more than one to help figure out when is the best time for you to have sex.

An ovulation predictor test may be able to help you time sex for pregnancy. These tests work a lot like pregnancy tests, in that you pee on test strips to determine when you're most fertile.

However, in some women, the tests give multiple "false positives."

Ovulation prediction kits detect the hormone LH, which usually peaks right before ovulation. Some women have many LH peaks before they actually ovulate. This makes the tests less than useful.

You may also decide to forgo trying to detect your most fertile time and have sex frequently throughout your cycle. There are many benefits to taking this approach.

What If You Still Can't Get Pregnant?

While it's sometimes possible to get pregnant on your own with irregular cycles, you should not ignore abnormal menstrual cycles. It's important to get checked out by your doctor, to confirm nothing serious is going on.

If it turns out that you are not ovulating, you may need fertility drugs to help boost your ovulation. Clomid is the most commonly prescribed drug for ovulatory dysfunction, and it has a high success rate.

Ovulation problems are a common cause of female factor infertility, with a pretty good treatment success rate. There's no shame in needing some help. Don't be afraid to seek it out.

More on getting pregnant:

Would you like to receive trying to conceive tips and fertility information every week? Sign up for a free fertility newsletter here.


Abnormal Uterine Bleeding. American College of Obstetricians and Gynecology Education Pamphlet. Accessed September 29, 2008. http://www.acog.org/~/media/For%20Patients/faq095.ashx?dmc=1&ts=20120128T1501101594

Menstruation. American College of Obstetricians and Gynecology Education Pamphlet. Accessed September 29, 2008. http://www.acog.org/~/media/For%20Patients/faq049.ashx?dmc=1&ts=20120128T1502272463

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