Irregular Periods? Could It Be PCOS or HA?
"PCOS and Hypothalamic Amenorrhoea are two of the most common reasons I see for irregular periods in practice. While they can seem similar on the surface, their root causes and treatment approaches are very different."
If your period has gone MIA or has become unpredictable, you're not alone. Missing or irregular cycles are one of the most common concerns I see in clinic. And while it might be tempting to jump straight to Google and self-diagnose, getting the right diagnosis from your doctor or medical specialist is really important. Not only to tell these two conditions apart, but also to rule out other causes such as thyroid dysfunction, perimenopause, and other hormonal conditions, so that the main drivers can be properly identified and treated.
Polycystic Ovary Syndrome (PCOS) and Hypothalamic Amenorrhoea (HA) can look similar from the outside (both can cause missing or irregular periods), but they have completely different underlying causes, hormone profiles, and treatment pathways. Treating one like the other can actually delay your recovery and make things worse.
Hypothalamic Amenorrhoea (HA) happens when your period disappears for several months because your body is under significant physiological stress. Essentially, your brain (specifically the hypothalamus) senses that conditions aren't safe for reproduction and turns off the signals that drive your menstrual cycle.
Common triggers can include a combination of:
- Chronic under-eating or not consuming enough energy
- Significant weight loss
- Intense or frequent exercise
- High levels of psychological stress
Left unaddressed, HA can have serious long-term effects including difficulty conceiving, reduced bone mineral density (which increases injury risk), and impaired gut function. The good news: HA is a functional condition, meaning it's often reversible with the right lifestyle interventions including improved nutrition, reduced exercise intensity, stress management, and addressing any disordered eating patterns.
PCOS is a complex endocrine-metabolic disorder that affects how the ovaries function. It's one of the most common hormonal conditions in women of reproductive age, and it looks very different to HA at a biochemical level.
PCOS is often characterised by a combination of:
- Insulin resistance
- Elevated androgen levels (male hormones)
- Inflammation
- Irregular or absent periods
It's worth noting that PCOS has different phenotypes, meaning not everyone with PCOS has the same symptoms or the same root causes. This is one reason why a personalised approach to management is so important.
PCOS can increase the risk of difficulty conceiving and is linked to higher rates of metabolic and mental health conditions, including type 2 diabetes, anxiety, and depression. Nutrition can play an important role helping to manage insulin resistance, inflammation, cravings, and fatigue.
Here's a quick reference comparison of how the two conditions differ across some key features, because the differences really do matter for how each is treated.
| Feature | HA | PCOS |
|---|---|---|
| Causes | Insufficient energy intake and/or chronic stress | Endocrine-metabolic disorder; elevated androgens and insulin resistance |
| Body type | Often lower BMI (but can happen in any body) | Often higher BMI (but can happen in any body) |
| Periods | Irregular, very light, or absent | Irregular or absent |
| Common symptoms | Low energy, cold hands/feet, low libido, frequent injury, poor recovery | Acne, facial/body hair growth, hair thinning, fatigue, possible weight gain |
| Common hormone profile | Low LH:FSH ratio · Low-normal androgens · Low oestrogen · Normal-elevated SHBG | High LH:FSH ratio · Typically elevated androgens · Low SHBG · Insulin resistance |
Common strategies include:
- Increasing overall energy intake, including adequate carbohydrates and fats
- Eating frequent meals and snacks throughout the day
- Reducing exercise intensity and overall training load
- Prioritising rest, sleep, and mental health support
- Addressing any disordered eating or negative body image concerns (if present)
- Optimising calcium and Vitamin D intake to support bone health
Common strategies include:
- Stabilising blood glucose levels throughout the day
- Focusing on low GI carbohydrate sources
- Incorporating an anti-inflammatory style of eating
- Including regular resistance training
- Supporting gut health, sleep quality, and stress management
- Targeted supplementation based on bloodwork (e.g. inositol, omega-3, Vitamin D)
Irregular or missing periods are not something to brush off or normalise. They're a sign your body needs more support.
Both PCOS and HA may seem similar but need very different approaches. Treating HA like PCOS (or vice versa) can delay recovery and management of the condition.
If your cycle is irregular or absent: don't guess. Get answers. Work with your GP and a dietitian who understands hormonal health to get a proper diagnosis and a plan that's specific to your needs.
Wanting personalised nutrition support for your periods?
Book a Free Discovery CallPersonalised dietitian support for PCOS, HA and hormonal health. Calgary and online.
