a sanitary pad with red glitter to represent irregular periods

Irregular Periods and Pregnancy: The Only Guide You Need

Is it here yet? Why is it not here yet? Wait a minute…am I pregnant

Playing the guessing game with Aunt Flo (or That Time of the Month) is a perpetual problem faced by those with irregular periods. While it could be a ‘nice’ problem — think not needing to deal with pads, tampons, or blood for a longer period — having an irregular period could be a concern if you are trying to conceive (TTC)

Here’s what you need to know about irregular periods and pregnancy, specifically how it could affect conception and how to increase your chances of baby-making success when trying to get pregnant.

Disclaimer: The information provided in this post is not intended as medical advice.

What Is Considered an Irregular Period?

You may have heard that the average cycle for a period is 28 days. However, this can differ from person to person. A 2020 global study analysed the menstrual cycle length of 1.5 million people aged 18 years and older and found that:

  • 89.04% had an average cycle length of 21-35 days 
  • 0.17% had a short cycle length of fewer than 21 days 
  • 8.60% had a long cycle length of more than 35 days

As such, your menstrual cycle can be considered regular if it falls within the 21 to 35-day window and lasts roughly the same length every cycle.

On the other hand, an irregular period has a cycle shorter than 21 days or more than 35 days. A period that lasts longer than 7 days, or less than 2 days, can also be counted as an irregular period.

Try tracking your cycle if you’re struggling with irregular periods and pregnancy. To help you determine if your period is regular or not (as well as figure out your fertile window, more on that later), you can track your periods by logging it on your calendar or using period tracker apps. Those concerned about data privacy may want to consider non-cloud-based period tracking apps like Drip and Euki. Such apps only store data locally and don’t enable third-party tracking.

What Causes Irregular Periods? 

Hormonal imbalances generally disrupt your menstrual cycle, causing irregular periods.

Besides that, there are various lifestyle and health factors associated with an erratic menstrual cycle:

  • Stress
  • Being overweight
  • Smoking, or have previously smoked
  • Alcohol consumption 

Other data has also shown that menstrual irregularities are associated with polycystic ovarian syndrome (PCOS) and may be a risk factor for diabetes.

As mentioned earlier, hormonal imbalance is usually the culprit behind an irregular period. If you’re trying to get pregnant with infrequent menstruation, get your hormone levels tested with an at-home hormone test kit. It can help paint a better picture of your reproductive health to see if you need to speak with a medical professional or not. For example, your test results may highlight any underlying health problems affecting your fertility levels — think anovulation (absent ovulation), endometriosis, and PCOS.

Shop The twoplus Hormone Test Kit

Let’s Look at Ovulation

If you’re wondering whether you can actually get pregnant with irregular periods, the answer is yes. That’s all thanks to ovulation, aka the one-day event within your fertile window when the egg is released from the ovary. Counting five days back from the day of the egg release, your fertile window encompasses this short time period in your menstrual cycle when you’re more likely to get pregnant.

Every month, one of your ovaries releases an egg. This typically happens 14 days before menstruation if you don’t experience hormonal imbalance.

The egg will travel from the ovary and into the fallopian tube. If sperm are already deposited in the vaginal tract and successfully made their way to the fallopian tube, the ‘winning’ sperm now has a chance to fertilise the egg there. Then the fertilised egg will move toward the uterus where it’s implanted to grow into a full-fledged foetus.

If the egg isn’t fertilised, the thickened uterine lining will shed and eventually flow out of your body through your vagina. The release of uterine tissue and blood is your menstrual period.

Fun fact: Contrary to popular belief, science explains that your ovaries don’t necessarily take turns ovulating every month. One study even highlighted that right-sided ovulation (when the ovary on the right side releases an egg) “favours pregnancy” more than the left side during artificial insemination!

Irregular Periods and Pregnancy: How Do They Affect Your Odds of Conception?

a calendar showing irregular period

It’s still highly possible for you to get pregnant even if you’re dealing with an irregular period. The only challenge is that you don’t know when your period might come.

This makes it more difficult for you to determine your fertile window and time sex around ovulation to maximise your chances of conceiving. Moreover, a person with a longer-than-usual menstrual cycle (i.e., more than 35 days) will likely have a lower frequency of ovulation.

For example, your best friend may regularly have her period every month, which means she ovulates about 12 times in a year. On the other hand, if you’re struggling with a sporadic cycle with extended breaks in between, you may only ovulate six times a year — that’s half the chances for conception!

And it’s not just simple maths.

Scientific data also suggested that people with irregular periods (i.e., “high menstrual cycle variability”) have lower odds of getting pregnant in each cycle than people with regular menstruation. Recent research also observed that those with regular periods “conceived more quickly.”



How To Get Pregnant With Irregular Periods

Even if your periods are irregular, you can still get pregnant, though it could be more challenging than someone who consistently ovulates every month.

For peace of mind, consult a licensed healthcare professional to determine that your irregular periods aren’t a sign of an underlying medical issue that can affect your chances of conception. For instance, an erratic menstrual cycle is a symptom of anovulation — the ovaries fail to release an egg during the menstrual cycle. This medical condition is one of the most common causes of infertility in people with ovaries.

If you’ve received a clean bill of health, there are a few things you can do to improve your chances of getting pregnant with irregular periods.

Have Regular Sex

If you find that ovulation tracking adds too much stress to your conception journey, one way is to have sex regularly instead of pegging it to your fertile window. Make time for intercourse at least once every 2-3 days as your schedule permits. This way, you can skip the stress of timed intercourse and boost your odds of getting pregnant.


Use an Ovulation Test Kit

But if a hectic lifestyle makes regular sex inconvenient — a common scenario for many of us trying to conceive — use an ovulation test kit to check if you’re ovulating.

Sure, ovulation testing can be more accurate for those with regular periods as you can easily pinpoint the start of your fertile window. Still, rest assured that ovulation test kits will work even with irregular menstruation. The trick is to test more often during your cycle.

twoplus Fertility’s Ovulation Test Kit (by Point of Care) is an at-home ovulation test that allows you to check the level of Luteinising Hormone (LH) in your body to predict your ovulation status anywhere, any time. The best part? You’ll get your results back in less than 10 minutes.

If you intend to use an ovulation test kit every other day to track your fertile period, we recommend getting the twoplus Ovulation Test Kit in bundles of four or six for extra cost savings. Bonus: The kit is discreetly packaged and comes with free delivery. 

Get The Ovulation Test Kit


Track Your Basal Body Temperature

If you haven’t heard, your basal body temperature refers to the temperature when your body is at rest. Besides measuring your hormone levels, you can also pay close attention to your basal body temperature when trying to get pregnant with irregular periods, otherwise known as the basal body temperature (BBT) method.

To track your BBT when trying to conceive, you should:

  • Note down your BBT before getting out of bed in the morning: Use a digital oral thermometer or a thermometer specifically designed to measure the basal body temperature. For a more accurate reading, get at least three hours of uninterrupted sleep each night. 
  • Be consistent in taking your BBT: Measure your basal body temperature at the same time every day (or as often as possible). Skip tracking when you’re travelling or if you drank alcohol the night before, as your results may be affected.
  • Record your temperature on a chart: This helps you understand your average basal body temperature. Keep an eye out for an increase of about 0.4 °C. When your BBT has stayed at the increased reading for three days, you have likely ovulated.

Do note that there are a lot of other factors that may affect your basal body temperature and skew the results of your BBT chart tracking, such as:

  • Stress
  • Shift work
  • Lack of sleep
  • Interrupted sleep cycles or oversleeping
  • Alcohol
  • Certain medical disorders and medications

Take note that the BBT method only shows whether ovulation has occurred but not when it happened. As such, BBT chart tracking may not be an accurate way to determine your fertile window.

Still, the BBT method has one important benefit: Consistent tracking of your basal body temperature over a few months can help you roughly gauge when you will ovulate in your cycle.

Inspect Your Vaginal Discharge

egg white symbolises vaginal discharge

Your vaginal discharge (aka cervical mucus) can also be an indicator of ovulation. When your cervical mucus is clear, viscous, and has the consistency of egg whites, this could be a sign that you are ovulating. The runny texture of your vaginal discharge also helps guide sperm along their journey to the cervix. 

How Do You Fix an Irregular Period?

Perhaps you’re wondering, “Can you make your irregular period regular?”

To answer the question, you must first identify the root cause of your erratic cycles to pursue the right solution. For instance, if chronically high stress is disrupting your natural menstrual frequency, you may want to find ways to reduce your stress levels or speak to a therapist for healthy stress management techniques.

Besides that, try positive lifestyle changes such as:

  • Eating a balanced, healthy diet 
  • Regular exercise to maintain a healthy weight and release endorphins
  • Quit smoking
  • Reduce your alcohol intake

Remember that these suggestions are not guaranteed to help regulate your menstrual cycle. To understand your reproductive health better, especially if you’re trying to conceive, speak with a medical professional about your irregular periods.


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Are you taking too long to conceive? Check out our Getting Pregnant 101 Guide for must-know TTC tips below & above 35 years old.