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PCOS vs Endometriosis - What’s the Difference?

on 10 Mar 2023 1:47 AM
Photo of a model uterus on a yellow background with medications surrounding

If you have a uterus or know someone who does, you may have heard of PCOS, endometriosis - or both! But what are they, and are they any different? Let’s break it down.


PCOS stands for Polycystic Ovarian Syndrome. Despite the name, it’s a condition that has less to do with actual cysts and everything to do with hormones - insulin and androgens in particular. The cause of PCOS is still unknown, but it’s thought that raised levels of insulin in the body cause the ovaries to function differently resulting in the release of more androgens. Genetic factors play a big role in this condition so if you have an immediate family member who has PCOS, there’s a 50% chance that you will develop it too.

The two main players in this condition are Insulin and Androgens and so many symptoms of this condition are more or less severe depending on the levels of these two types of hormones.


Insulin is an important hormone that allows the cells in our body to use glucose from the foods we eat as energy. However, around 85% of women who have PCOS have insulin resistance which means their cells don’t respond normally to the available insulin which results in unstable glucose levels in their blood. When this happens, our bodies react by producing more insulin to try and regulate our glucose levels. This boost of insulin increases the production of androgens in the ovaries.

Insulin resistance can be caused by a variety of factors such as lifestyle and genetics and puts you more at risk of developing diabetes.


Androgens are hormones that are present in all people and high levels of these hormones cause symptoms such as increased body and facial hair growth, scalp hair loss, and acne. Higher levels of androgens in the body can contribute to changes in the menstrual cycle, causing symptoms such as irregular periods and irregular ovulation. These symptoms can reduce your fertility.

Other symptoms include mood changes, weight gain, irregular periods, and periods disappearing altogether.


Endometriosis is a long-term condition that gradually gets worse where cells that are similar to the endometrial cells that line the uterus are found in other parts of the body. They usually occur in the pelvis and affect a person’s reproductive organs.

During a period, endometrial cells along the lining of the uterus thicken, break down, and bleed. When cells do this outside of the uterus, they stick to other organs causing adhesions, scarring, and excruciating pain. Fatigue, nausea, and bloating are also other issues that can come with this condition.

Similar to PCOS, researchers are still unclear of the cause of endo. However, we have been able to identify some factors with family history being the main one. Long and heavy periods lasting more than five days, low body weight, and alcohol use are other factors thought to play a role in causing endometriosis.

Both endo and PCOS can make it difficult to fall pregnant depending on how severe the conditions are. They both need long-term symptom management often involving several different health specialists such as gynaecologists,  dieticians, endocrinologists, and a psychologist.

For more information, see:

Better Health Channel (PCOS)
Jean Hailes (PCOS)
Pregnancy, Birth and Baby: PCOS and pregnancy
ASK PCOS: Evidence-based information for women with Polycystic ovary syndrome

Better Health Channel (Endo)
Sexual Health Victoria
Endometriosis Australia
Jean Hailes: Endometriosis multilingual fact sheets
Royal Women's Hospital
Pregnancy Birth and Baby: How endometriosis affects pregnancy