Conceiving with Irregular Periods: Timings & What to Know

Conceiving with Irregular Periods: Timings & What to Know

If you’re wondering how to get pregnant with irregular periods, you’re not alone.

Even if the textbooks would have us believe that all women have a clockwork 28-day cycle, that’s only true for about 13% of women.

TTC with irregular periods can be a frustrating road, but there is hope.

So let’s take a look at the things that link irregular cycles and fertility, and ask what you can do to increase your chances of getting pregnant each month.

In this article 📝

  • Is it harder to get pregnant if you have irregular periods?
  • What causes irregular periods?
  • How can I get pregnant fast with irregular periods?
  • Getting pregnant with an irregular cycle
  • The last word on TTC with irregular periods

Is it harder to get pregnant if you have irregular periods?

We’re going to start with the bad news.

Yes, it may be a little harder to get pregnant with irregular cycles, but it isn’t impossible.

But let’s step back for a minute and make sure your cycle is actually irregular.

According to doctors, a cycle anywhere between 24 and 38 days is actually considered normal, and a couple days difference now and then is nothing to worry about.

If you have a regular period but it doesn’t match the 28-day cycle used by most fertility calculators, you can still easily predict your ovulation date with some tracking and a tiny bit of math.

Start by tracking your period for a few months to see just how long it usually is.

Then you’ll want to subtract 14 days from your overall cycle length.

This is because most women with regular periods, regardless of how long their cycle is, usually ovulate about 14 days before their period comes.

So, if your cycle consistently lasts about 38 days, you can predict that you ovulate around day 24.

If your cycle lasts 24 days, you probably ovulate around day 10.

The real challenge comes if your period is truly irregular.

If your cycle is shorter than 24 days, longer than 38 days, or varies significantly from month to month, then you technically have irregular periods, and it will be more challenging to predict ovulation.

The bottom line? If it’s harder to predict when you’re ovulating, it’s harder to time sex, which is why it generally takes longer to get pregnant with irregular cycles.

What causes irregular periods?

So many things can affect your cycle–from stress to breastfeeding to traveling to illness.

Sometimes it’s just a blip, but if you track your cycle over several months and notice that it’s often shorter than 24 days, longer than 38 days, or that it swings between two extremes, it’s probably safe to say that you have irregular periods.

What’s more, a lot of the conditions that might lie behind an irregular cycle can make it harder to get pregnant. But before we panic, let’s remember that:

  1. You’re not alone, and these conditions are more common than a lot of people realize.
  2. With blood tests, laparoscopic exams, and ultrasounds, diagnosis and treatment are very much on the cards.
  3. When the conditionals are managed, pregnancy is a very realistic goal for many women.

Most of the conditions that cause irregular cycles and make it harder to get pregnant involve an imbalance in the hormones that control ovulation.


PCOS is Polycystic Ovary Syndrome.

This means that fluid-filled cysts develop in your ovaries, which can stop/affect healthy eggs from being matured and released.

The condition can also make your estrogen levels erratic, so you’re fertile at unpredictable times.

There’s more information on how to get pregnant with PCOS and irregular periods here.


Endometriosis, (aka Endo), is a painful condition where the tissue that should form the lining of your womb grows beyond the uterus.

The endometrium or the lining can extend and grow on the fallopian tubes, ovaries, and even until the abdomen.

Different aspects of this condition can make it harder to get pregnant.

Along with that, hormonal changes, patches of endometrial tissue blocking your fallopian tubes, or increased inflammation in different parts of your body may have a knock-on effect.

If you’re struggling with endometriosis pain, there are some things that can help. Our Peanut community loves the OOVI pulse therapy kit, which can also help with period pain.

Over- or under-active thyroid

Your thyroid is partly responsible for making the hormones that regulate ovulation.

If it’s not producing the right balance of these hormones, it can affect your chances of getting pregnant.

Insulin resistance:

When it becomes harder for your body to absorb glucose, your blood sugar levels stay consistently higher.

This in turn means that your body starts to produce less estrogen, which is essential for ovulation.

The first thing to note is that there are some things that can help to manage these conditions without medications:

  • Losing weight
  • Avoiding certain food groups that trigger your symptoms
  • Building more exercise (especially strength training) into your weekly routine

But it goes without saying that you should try to make these lifestyle changes alongside consulting your doctor and getting medication, if you need it.

High prolactin levels

Prolactin is the hormone responsible for breast milk production.

Prolactin levels that are higher than normal can interfere with the normal production of hormones such as estrogen and progesterone.

This causes irregular or missed periods due to changes or a stop in ovulation.

How can I get pregnant fast with irregular periods?

Unfortunately, we can’t guarantee a quick conception with irregular periods–or even with regular periods, for that matter!

But here are some steps you can take to increase your chances of getting pregnant each month.

Figure out when you’re ovulating

This is usually the first piece of advice for anyone who’s TTC, but how do you know when you’re ovulating if you have irregular periods?

Information is power, and it’s helpful to start tracking your symptoms as soon as you can.

At home, you could try these things to get to know your body:

  • Note when you have ovary pain (especially on one side). This can be caused by cysts, but it’s also a symptom of ovulation for about 40% of women.
  • Check your cervical mucus. When you’re ovulating, it should be clearer and stretchier, a bit like egg white.
  • Check the position of your cervix. You can feel your cervix as the small, donut-shaped muscle at the top of your vagina. It’s higher, softer, and more open around the time you’re ovulating.
  • Track your basal body temperature (i.e. your body temperature immediately after you wake up). It should fall slightly for a few days around the middle of your cycle and then be suddenly higher on the day you ovulate

Using ovulation sticks is also an option, but this can get expensive if you have to test on more than a couple of days a month, and conditions like PCOS can, unfortunately, cause false positives.

If you’ve tried these things for a few months and are still none the wiser, the only official way to know when you ovulate is with blood tests and an ultrasound.

This scan checks how your eggs are developing and measures how thick the lining of your uterus is.

Getting pregnant with an irregular cycle

First off, if you already know that you have a condition like PCOS or endometriosis, it’s not unreasonable to schedule a doctor’s appointment at the beginning of your TTC journey to make a plan.

And you should also book an appointment if you’ve been TTC for 12 months with no success (or six months, if you’re over 35).

The first piece of advice will probably be to have sex regularly (as in, every two days) throughout your cycle, to make sure that you cover the days when you’re fertile, whenever they happen to be.

Fertility drugs may also be an option. Depending on your situation, your doctor might prescribe Clomid, an oral tablet, to encourage your body to produce fertility-stimulating hormones, or you might get these hormones injected directly into your body.

Oral tablets such as Clomid promote FSH and LH production, which can help with the growth of the egg.

Both these drugs increase your chances of getting pregnant each month.

The last word on TTC with irregular periods

Even if your body is a Swiss clock, TTC can be tough.

And the journey can be even more of a rollercoaster if you’re TTC with irregular periods.

Talking helps, and you’re not alone.

The women in the Peanut community are always there if you need a friend on the road.

💡 You might also like:
Prostaglandins and Period Pain: What You Need to Know
Can You Get Pregnant Right Before Your Period?
Can You Get Pregnant Right After Your Period?
Things You Should Know About Your Period, But Don’t
Can You Have Two Periods in One Month?
How Late Can a Period Be?
How to Reduce Period Pain
What to Know About Black Period Blood
Boobs Sore After Period? What to Know
Having Sex on Your Period: What to Know
Are There Drinks That Help With Period Cramps?
What Does Brown Discharge Before My Period Mean?
8 Signs Your Period is Coming Tomorrow
Why Am I So Hungry On My Period?
The 411 on Period Poop
Why Do I Crave Chocolate On My Period?
Blood Clots During Your Period: Yes, It’s Normal
How Long Do Periods Last? When Do Periods End?
Why Did My Period Come Early? 10 Reasons
The Menstrual Cup: Do They Really Work?

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