Better Me

Can You Get Pregnant with an Irregular Period?

Not all women’s periods operate like clockwork. Some women have their periods right on schedule every 28 days, while other women’s periods are irregular and unpredictable.

An irregular period can be frustrating for anyone, but what about if you’re trying to get pregnant? It can be upsetting if you’re trying to conceive and are having difficulties.

There are a number of factors that affect a woman’s ability to become pregnant and one of those is irregularity in your periods. Here’s everything you need to know about the link between irregular periods and pregnancy.

What are considered irregular periods?

Just like no two people are alike, women’s menstrual cycles aren’t alike either. However, there are standard parameters of what’s considered “normal” versus irregular.

“A ‘normal’ cycle is anywhere between 21 to 35 days with consistently not more than a two to three day variance from cycle to cycle,” said Emilee Sandsmark, MD, an OBGYN at Banner Health Clinic in Loveland, CO. “Any cycle that occurs more or less frequently than this is considered abnormal, as is a woman who experiences cycles that are 24 days, then 29 days, then 34, etc.”

If your period is occurring more frequently than 21 days (polymenorrhea), this is considered abnormal. If it occurs less frequently than every 35 days (oligomenorrhea), this is also considered abnormal.

What causes irregular periods?

There are a number of things that can affect your period—from stress to weight fluctuations to medications and medical conditions like polycystic ovarian syndrome (PCOS) or thyroid issues.

But in general, irregular ovulation is what causes irregular menstrual cycles, Dr. Sandsmark said. It’s a common misconception that irregular periods cause irregular ovulation, as it is typically the other way around.

“Hormones released by the hypothalamus and pituitary gland (both in the brain) and the ovary are the messengers that regulate monthly cycles,” Dr. Sandsmark said. “There can be a number of abnormalities at any of these steps that can cause irregular ovulation and abnormal periods.”

If you’re experiencing irregular periods, it’s best to talk to your health care provider about ways to treat the underlying issues to allow for more predictable ovulation and more regular periods.

Can I get pregnant with an irregular period?

“Yes, because women with irregular periods can still ovulate, however, the timing of ovulation may be harder to predict,” Dr. Sandsmark said.

Sometimes making lifestyle changes can regulate previously erratic periods and help you conceive. Some women, however, may require the use of other treatment options.

Here are some general guidelines when it comes to conception and medical evaluations:

  • If you’re younger than 35 years old and have been having unprotected sex for 12 months with no success
  • If you’re over the age of 35 and have been having unprotected sex for 6 months or more
  • If you’re 40 years old or older

[Also read “Diagnosing Fertility: Common Tests on the Pathway to Pregnancy”]

What can I do to determine if I’m ovulating?

While one of the biggest indicators of ovulation is a regular menstrual cycle, there are electronic apps and ovulation predictor kits you can purchase. But be mindful, Dr. Sandsmark said, as “some of these tools can vary in quality and data on their usefulness are limited.”

Another issue is that unless you have regular cycles, both the apps and predictor kits can be more challenging to use. So those who may need them the most (i.e., you), might have the most difficulty using them.

The most accurate and helpful tool is bloodwork. “Bloodwork ordered by your physician done on specific days of your menstrual cycle can help determine the best options for trying to conceive,” Dr. Sandsmark said.


Irregular ovulation can lead to irregular periods. Irregular ovulation doesn’t mean you can’t get pregnant, but it can make your ability to conceive a little harder. Seek professional and medical help to regulate your menstrual cycle and better determine when you ovulate each month.

To find a Banner Health specialist near you, visit

Related Articles:

Women's Health Pregnancy