If your menstrual periods are irregular, it may be more difficult for you get pregnant – and it may not. Whether irregular periods will affect your ability to conceive depends on the underlying reason for the variation in cycle length, as well as on other health and fertility factors.
Irregular periods are sometimes a symptom that you are not ovulating, and without ovulation, conception is impossible. Therefore, the first thing you need to do is find out whether you are ovulating or not.
If you are ovulating, your main challenge is to find your fertile period in order to optimize intercourse timing. If you are not ovulating, you will likely need medical assistance in order to get pregnant.
What are irregular periods?
Your cycle length is the number of days between each of your periods.
A slight variation in cycle length is normal, but your cycles are considered irregular if you have more than five cycles a year that are more than five days longer or shorter than your average cycle length.
Cycles that are always shorter than 21 days, or longer than 36 days, are also considered irregular cycles.
Read more: Understanding the menstrual cycle
How to find out if you are ovulating
Irregular periods often indicate that you are not ovulating, a condition clinically known as anovulation. Because you cannot get pregnant if you are not ovulating, it is important to confirm whether you are ovulating or not.
The simplest method is to chart your basal body temperature (BBT), by measuring and recording your body temperature first thing every morning. If you are ovulating, your temperature chart will show a shift from lower temperatures before ovulation to slightly higher temperatures after ovulation. If you can’t detect this two-phase pattern on your charts, you are probably not ovulating. Learn more about BBT charting
You can also ask your doctor or gynecologist for blood tests to confirm ovulation. You may be asked to take tests at different times in your cycle in order to measure the levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH) before ovulation, and of progesterone after ovulation. Some doctors may also do a mid-cycle ultrasound to see if eggs are developing normally in your ovaries.
How to find your fertile period with irregular cycles
If your temperature charts and/or your blood tests confirm that you are indeed ovulating, your most important task is to find out when ovulation happens so you can make sure to have intercourse during your most fertile period, which is the last 2-3 days before ovulation.
If you and your partner are making love three times per week or more, you will most likely have intercourse at least once during your most fertile days in any case. And if you are relaxed about how long it may take to get pregnant, you may want to leave it at that.
However, your probability of conception will increase with every intercourse in your fertile period. And if you are experiencing difficulties getting pregnant, or you just want to make sure you give yourself the best possible odds in every cycle, you will want to identify your most fertile days so you can time your lovemaking perfectly. Unfortunately, basal body temperature charting only identifies the ovulation day once ovulation is over, when it is already too late to conceive in that cycle. To predict ovulation and optimize intercourse timing, you need different methods.
The simplest tools are ovulation tests, or ovulation predictor kits. Ovulation tests detect the increased presence of luteinizing hormone (LH) in your urine which occurs 12 to 36 hours before ovulation. A positive ovulation test means that ovulation is likely to happen within the next day or two, and that it is time to take your partner to bed.
However, when your menstrual cycles are very irregular, it can be difficult to know when to start testing. You may also have to spend a lot of tests before you get a positive result. Many women with irregular cycles therefore prefer using a fertility monitor which predicts ovulation based on changes in electrolyte concentration (salinity) in saliva samples, rather than LH in the urine.
Possible reasons why you are not ovulating
If you are not ovulating, you cannot get pregnant, and you are likely to need medical assistance in order to conceive. Here are some of the most frequent reasons for anovulation.
Polycystic Ovarian Syndrome (PCOS)
Polycystic ovary syndrome (PCOS), a hormonal imbalance, is the most frequent cause of infertility caused by anovulation. Some women with PCOS do still ovulate and can get pregnant naturally, but PCOS often leads to infertility or subfertility. Besides irregular periods, other typical symptoms of PCOS include unexplained obesity or weight gain, insulin resistance, high blood pressure, and excess hair growth on the body and face.
Reducing insulin resistance through medications such as metformin often helps restore ovulation in women with PCOS. If not, your doctor may prescribe ovulation-inducing medications, typically clomiphene citrate.
Underweight or overweight
Both underweight and overweight are associated with an increased risk of anovulation.
In underweight women, anovulation is usually due to hormonal imbalances and/or nutritional deficiencies caused by undernourishment. Gaining a few pounds to achieve a healthy body mass index (BMI) will often be enough to restore a normal menstrual cycle.
The cause-effect relationship between overweight and anovulation is often more complex. For example, increased insulin levels are a frequent cause of infertility in overweight women. It isn’t the excess body fat that causes anovulation; the abnormal insulin levels are the underlying cause of both the weight and the ovulation problems. Losing excess weight may help get your cycles back on track and will also help sustain a healthy pregnancy, but do see your doctor to discuss whether you need an additional treatment to restore ovulation.
Extreme dieting or very intense exercising may also disrupt the normal functioning of your reproductive system. If you suspect this is your case, you may want to consult a dietician to help you establish a balanced diet and exercise regime.
An underactive thyroid gland is another frequent cause of anovulation. This condition, known as hypothyroidism, affects the production of reproductive hormones including estrogen and FSH. Sometimes hyperthyroidism, or an overactive thyroid, may also result in irregular menstrual cycles and anovulation. When you consult your doctor about your irregular menstrual cycles, ask for a check of your thyroid levels.