Five Questions to Ask About Irregular Periods

1. What is an irregular period? 

A period occurring more frequently or less frequently than a typical monthly cycle.   

The definition varies depending on the age of the patient. In the first two to three years of an adolescent patient starting their period, there will be some irregularity as the body establishes monthly periods.  

Anywhere from 21 to 45 days between cycles is considered normal in the early years. 

Anything more than three months between cycles or more frequently than 21 days between cycles would be considered an irregular period, even within the first three years of a child starting their period.  

As patients age, periods typically become more consistent, roughly 21 to 35 days between cycles. Once a regular monthly period is established, it would not suddenly become irregular without an underlying cause.   

2. What’s the most common reason that periods are irregular?   

The most common reason a period might be irregular in the first two to three years after periods start is hypothalamic pituitary ovarian (HPO) axis immaturity. This means the body is still sorting out the coordinated signaling every month from the brain to the ovaries to the uterus to have a set period cycle.   

As patients get older and pass the age for HPO axis immaturity, other common causes include thyroid disease and polycystic ovarian syndrome (PCOS), which occurs in about one in 10 patients. These causes require treatment.   

Because the symptoms of PCOS can overlap with puberty, including increased hormones, excess hair and acne, parents often worry their child's period irregularity might indicate PCOS. However, this is not always the case. Gynecologists recommend giving a child's period time to become regular in at least the first two to three years before making a PCOS diagnosis.    

3. What evaluation would a patient have for an irregular period?   

When a patient comes to the ACH gynecology clinic with an irregular cycle, the first thing our medical experts do is document the patient’s period history, asking: 

• When the first period started
• Frequency of periods over time   
• How long their period usually lasts  
• Amount of menstruation products a patient uses each day of their period  
• Any other symptoms associated with their cycle   

A pelvic exam or ultrasound is not typically required to evaluate an irregular period cycle in a pediatric or adolescent patient. If the questionnaire indicates HPO axis immaturity, gynecologists may recommend using a menstrual calendar to see if the cycle regulates over time.   

Bloodwork may be drawn to test for causes of irregularity, like thyroid disease, if a patient’s period has been irregular for a significant amount of time. 

4. Why take irregular periods seriously?   

When patients go significant amounts of time without a cycle and eventually get their period, it can be heavier or longer than a regular menstrual cycle. As patients get older, if they continue to have prolonged episodes of no periods, it can impact their uterine health.   

5. What is the treatment for irregular periods?   

Treatments for irregular periods vary. It may include a menstrual calendar and observation, a short course of medication or hormonal therapies to regulate a cycle.