Getting pregnant can be challenging, and can become even more so if you have irregular periods. However, you are not alone – up to one third of patients diagnosed with infertility have issues with irregular periods.

What are considered irregular periods?

Well, the average menstrual cycle occurs every 28 days. Cycles that are shorter or longer by more than 7 days are considered abnormal. In other words, cycles that are shorter or longer than every 21-35 days.

If your cycle length falls outside this range, you may not be ovulating (releasing an egg) each month, which will decrease your chances of getting pregnant. The medical term used to refer to this set of problems is “anovulatory disorders.” There are different causes for anovulation, and it is recommended that you talk with your gynecologist if this is a regular problem for you.

Some of the reasons that women can fail to ovulate are:

• weight-related (being too thin or too heavy)
• an overactive or underactive thyroid
• extreme stress or exercise
• and in rare cases, benign or cancerous growths within the brain.

However, the most common reason for irregular periods and anovulation is a disorder called Polycystic Ovary Syndrome (PCOS). PCOS is a hormonal disorder that affects 5-10% of all females. Women are often unaware that they have this diagnosis until they start trying to conceive, since many of them are placed on birth control as teenagers to help regulate their periods.

The diagnosis of PCOS is made using 3 criteria:
(1) the inability of the ovaries to release an egg on a regular basis (anovulation resulting in irregular periods)
(2) signs of increased male hormone levels such as acne or hair growth in certain areas; and/or
(3) polycystic-appearing ovaries on ultrasound. If you have two out of three of these, you fit the diagnosis of PCOS.

Why is it important to determine the cause of irregular periods?

If one the above problems is identified, your doctor or a fertility specialist can talk about ways to treat the underlying issue to allow for more predictable ovulation and more regular periods. Some of these underlying conditions can have other effects on your overall health as well. For example, patients with PCOS are at higher risk for diabetes, high blood pressure and overgrowth of the uterine lining.

Women who are not trying to conceive:
Your doctor may recommend birth control pills to help regulate your periods. This is so that your period comes monthly.

If you are trying to conceive:
Your doctor can help determine if you would benefit from taking a medicine to assist with ovulation. Clomiphene citrate is the most commonly used ovulation-inducing fertility medicine. It is taken orally for 5 days of your cycle. This helps induce an egg to grow within the ovary so that you can ovulate and potentially become pregnant.

Original post February 2016
Updated May 2021