How to Get Pregnant With Irregular Periods

Tips for getting pregnant with irregular periods

 Verywell / Brianna Gilmartin 

Can you get pregnant with irregular periods? Yes, but it may be more difficult for you than it is for someone with regular cycles. According to one study, women whose menstrual cycles varied by less than two days were twice as likely to get pregnant over a given period of time than women whose cycles varied by more than six days.

Another study found that women with regular cycles were four times more likely to get pregnant than those whose cycles varied by more than 10 days. Some women with irregular cycles will need to use fertility treatments. Sometimes, making lifestyle changes can regulate previously irregular periods and help you conceive.

How easily you'll be able to conceive depends on:

Are Your Cycles Truly Irregular?

An irregular period is defined as a menstrual cycle that is either shorter than 21 days or longer than 36 days. Your cycle may also be considered irregular if it varies significantly from month to month. For example, if one month your cycle is 23 days, and another it's 35, your cycles would be considered irregular.

Research has found that variations in cycle length are associated more strongly with infertility than just having a shorter or longer regular cycle. In other words, if your cycles tend to be slightly longer than the normal range, but they are consistently that length, you may be less likely to experience fertility problems than someone whose cycles vary significantly but the length falls within the norm.

If your cycles are off by a day or two from month to month, you don’t need to worry. It’s when the variations are longer—five or more days—that you may face fertility difficulties.

An occasional irregular cycle is also normal. Stress or illness can delay ovulation or menstruation, causing your cycle to be longer, and sometimes shorter, than usual. If you have just one or two of these "off" periods a year, you don't need to worry. However, if your cycles are frequently irregular—or you go quite a long time between menstrual cycles—you should see your doctor for an evaluation.

Detecting Ovulation When Cycles Are Irregular

If you are ovulating, but irregularly, you'll need to make a special effort at determining your most fertile time. There are many ways to predict ovulation. You might need to use more than one to help figure out when is the best time for you to have sex.

Ovulation predictor 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." This is especially common in women with PCOS.

Another possible pitfall of using these tests when your cycles are irregular is that you'll need to use more than the average number of test strips. You don't use the tests your entire cycle, but only around the general time you might expect to ovulate. When your cycles are irregular, that possible ovulation window may be longer than it is for other women.

You may want to consider charting your basal body temperature (BBT). BBT charting can show you when you actually ovulated. You can also share your BBT charts with your doctor. They may be able to use this information to make a diagnosis.

A Better Method of Conceiving With Irregular Cycles

You may also decide to forgo trying to detect ovulation and just have sex frequently throughout your cycle. Some couples find timing sex for pregnancy stressful. This avoids that stress. You won't be trying to have sex when you get the positive ovulation test result. You'll just have sex, frequently, all month long (ideally, every other day).

With this method, you don't have to worry about missing ovulation. If you're having sex three to four times a week, you're likely to have sex on a fertile day.

Causes of Irregular Cycles

Irregular cycles may point to a subtle hormonal imbalance. You may still be ovulating every month, but your ovulation day may vary. If you're ovulating, you may be able to get pregnant without the help of fertility drugs. Here are some possible causes of irregular cycles that are also infertility risk factors.

Anovulation

However, 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 without the help of fertility treatments.

Polycystic Ovarian Syndrome (PCOS)

Irregular periods may be a sign of polycystic ovarian syndrome (PCOS). PCOS is a common endocrine disorder affecting 1 in 8 women. Not everyone with PCOS will experience infertility, but many will take longer to get pregnant. Women with PCOS also have a higher risk of early miscarriage.

Thyroid Imbalance

An underactive or overactive thyroid can cause irregular periods, as well as infertility. Other possible symptoms of a thyroid imbalance include weight changes, difficulty falling asleep or feeling tired all the time, unexplained anxiety or depression, or problems with constipation or diarrhea.

Hyperprolactinemia

Prolactin is a hormone primarily responsible for stimulating the breasts to produce breast milk. Hyperprolactinemia is when the hormone is elevated even if a woman is not pregnant or currently breastfeeding. (Hyperprolactinemia can also occur in men.)

Abnormally high levels of prolactin can cause irregular periods or even cause your periods to cease completely. Other possible symptoms may include swollen or tender breasts, leaking breast milk from the nipples, or painful sexual intercourse (from vaginal dryness).

Primary Ovarian Insufficiency (POI)

Also known as premature ovarian failure (POF), primary ovarian insufficiency can cause irregular or even completely absent periods. Low estrogen levels sometimes occur along with POI/POF, and this can lead to symptoms like vaginal dryness, painful sexual intercourse, hot flashes or night sweats, difficult sleeping, or unexplained depression or anxiety.

Obesity

Obesity is the most common preventable cause of irregular periods and decreased fertility. Obesity can cause irregular cycles as well as difficulty conceiving. Sometimes, weight problems are caused by an underlying and undiagnosed hormonal imbalance. For example, both PCOS and hypothyroid can cause sudden weight gain and difficulty with losing weight.

If you’re struggling with your weight, experience a sudden increase in weight despite not changing your lifestyle significantly, or have great difficulty losing weight, talk to your doctor. If your weight problems are being caused by a hormonal imbalance, your doctor may be able to treat that problem—and that may, in turn, help you lose weight. 

Underweight

Just as being overweight can cause irregular cycles, being significantly underweight can also lead to irregular periods and fertility problems. Eating disorders are a risk factor for infertility and absent periods as well.

Extreme exercise and extreme dieting are also potential causes of irregular cycles. Female athletes are more likely to experience infertility for this reason.

Medications to Help You Conceive

If it turns out that you are not ovulating, you may need fertility drugs to help boost your ovulation. Even if you are ovulating, if ovulation is irregular or occurring very late in your cycle, fertility treatments may help.

Clomid is the most commonly prescribed drug for ovulatory dysfunction, and it has a good success rate. Another possible option is the drug letrozole. This cancer drug is used off-label to trigger ovulation. Research has found it to be possibly more effective than Clomid in women with PCOS.

While not a fertility drug, another medication your doctor may suggest trying is the diabetes drug metformin. Metformin may help women with insulin resistance and PCOS ovulate on their own. If these medications don't work, your doctor may suggest moving onto injectable fertility drugs (gonadotropins)IUI treatment, or IVF.

If your irregular cycles are caused by primary ovarian insufficiency, your fertility treatment options may be limited. In many cases with POI, IVF with an egg donor is needed to conceive. This isn’t always the case, however. Talk to your doctor about your options.

If the cause for your irregular cycles is a thyroid imbalance or hyperprolactinemia, treating these problems may regulate your periods and return your fertility to normal. This is why getting evaluated by a doctor is essential.

Lifestyle Changes and Supplements to Regulate Ovulation

Fertility drugs aren't your only option. You may be able to make lifestyle changes, depending on the cause of your irregular cycles.

If you are overweight, losing some weight may be enough to jumpstart ovulation and help you conceive. Research has shown that obese women who lose just 10% of their body weight can start ovulating on their own again.

Remember, though, that some weight problems are caused by an underlying hormonal imbalance. Don’t assume your obesity is just a question of eating right. See your doctor, and then make a weight loss plan. 

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. If your issue is over-exercise, cutting back may regulate your cycles. If you’re an athlete, speak to your doctor about your options. You may need to take a break from your sport to jump-start your cycles again.

You may want to consider trying a fertility supplement (only after consulting with your doctor). Two fertility supplements that may help regulate irregular cycles are myo-inositol and chaste tree berry (vitex agnus-castus). Whether or not these supplements can truly be effective in regulating periods and improving fertility is has not yet been determined.

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. This doesn't apply if there are signs of a problem. Irregular cycles are 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.

A Word from Verywell

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. 

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