Endometriosis
Period pain so bad it stops your day, pain during sex, or trouble conceiving? These can be signs of endometriosis — a common but often-missed condition where tissue like the womb lining grows outside the uterus.
Affects roughly 1 in 10 women of reproductive age worldwide— WHO / global prevalence estimates
Affects roughly 1 in 10 women of reproductive age worldwide— WHO / global prevalence estimates
General education, not a diagnosis. SHELY is pre-launch — “Talk to someone” adds you to our experts waitlist; we don’t offer bookings yet.
Endometriosis is a condition where tissue similar to the lining of the womb (the endometrium) grows in places it shouldn't — most often on the ovaries, fallopian tubes, and the lining of the pelvis. Like the womb lining, this tissue responds to your monthly hormones: it thickens and bleeds with each cycle. But because it has no way to leave the body, it causes inflammation, pain, and over time scar tissue and adhesions that can stick organs together.
The hallmark is pain that is cyclical and severe — period pain that's far beyond ordinary cramps, often building in the days before bleeding. But endometriosis is also remarkably variable: some women with extensive disease feel little, while others with small amounts are in significant pain. This mismatch, plus the fact that 'bad periods' are so often normalised, is why diagnosis is frequently delayed by years.
It's a chronic condition, not an infection or a cancer, and it isn't caused by anything you did. While there's no cure yet, pain and fertility can be managed well — and naming it is the first step out of years of being told the pain is 'just part of being a woman.'
Signs & symptoms
- Severe period pain that interferes with daily life (dysmenorrhoea)
- Chronic pelvic pain, sometimes between periods
- Pain during or after sex (deep dyspareunia)
- Pain when passing urine or stool, especially during your period
- Heavy or irregular menstrual bleeding
- Bloating or a swollen, tender abdomen ('endo belly')
- Fatigue, particularly around your period
- Difficulty getting pregnant
- Pain that often starts days before bleeding and eases after it ends
Types
Superficial peritoneal endometriosis
The most common and mildest form — small deposits on the lining of the pelvis (peritoneum).
Ovarian endometrioma ('chocolate cyst')
Fluid-filled cysts on the ovaries containing old blood, which can affect ovarian function and fertility.
Deep infiltrating endometriosis (DIE)
Tissue that grows deeper into pelvic organs such as the bowel, bladder, or the ligaments behind the uterus, often causing the most severe pain.
Adenomyosis (related condition)
When endometrial-like tissue grows into the muscular wall of the uterus itself, causing heavy, painful periods; it often coexists with endometriosis.
What causes it
- Retrograde menstruation — period blood flowing backward through the tubes into the pelvis
- Cells outside the uterus transforming into endometrial-like tissue
- Genetics — endometriosis often runs in families
- Immune system differences that fail to clear the misplaced tissue
- Hormonal (oestrogen) sensitivity that drives the tissue to grow
- The exact cause isn't fully understood and is likely a mix of these factors
When to seek help
See a doctor if period pain regularly stops you from going to work, school, or daily activities, if you have pain during sex or when going to the toilet, or if you've been trying to conceive without success. Don't wait for the pain to become unbearable — endometriosis is often dismissed as 'normal' bad periods, so it helps to keep a symptom diary and ask directly whether endometriosis could be the cause.
How SHELY helps
SHELY Care
Track pain, bleeding, and how each day affects you — a clear cyclical record is powerful evidence to bring to your doctor and shorten the road to diagnosis.
Symptom Checker
Describe your pain pattern to understand whether it points to endometriosis and what to raise with a clinician.
SHELY Varsity
Honest guides on living with endometriosis — pain relief, hormonal and surgical options, fertility, and self-advocacy in appointments.
Not sure what comes next?
Pick a topic to explore what we know about Endometriosis. Educational only — not a diagnosis.
- Severe period pain that interferes with daily life (dysmenorrhoea)
- Chronic pelvic pain, sometimes between periods
- Pain during or after sex (deep dyspareunia)
- Pain when passing urine or stool, especially during your period
- Heavy or irregular menstrual bleeding
- Bloating or a swollen, tender abdomen ('endo belly')
- Fatigue, particularly around your period
- Difficulty getting pregnant
- Pain that often starts days before bleeding and eases after it ends
- Retrograde menstruation — period blood flowing backward through the tubes into the pelvis
- Cells outside the uterus transforming into endometrial-like tissue
- Genetics — endometriosis often runs in families
- Immune system differences that fail to clear the misplaced tissue
- Hormonal (oestrogen) sensitivity that drives the tissue to grow
- The exact cause isn't fully understood and is likely a mix of these factors
Superficial peritoneal endometriosis
The most common and mildest form — small deposits on the lining of the pelvis (peritoneum).
Ovarian endometrioma ('chocolate cyst')
Fluid-filled cysts on the ovaries containing old blood, which can affect ovarian function and fertility.
Deep infiltrating endometriosis (DIE)
Tissue that grows deeper into pelvic organs such as the bowel, bladder, or the ligaments behind the uterus, often causing the most severe pain.
Adenomyosis (related condition)
When endometrial-like tissue grows into the muscular wall of the uterus itself, causing heavy, painful periods; it often coexists with endometriosis.
See a doctor if period pain regularly stops you from going to work, school, or daily activities, if you have pain during sex or when going to the toilet, or if you've been trying to conceive without success. Don't wait for the pain to become unbearable — endometriosis is often dismissed as 'normal' bad periods, so it helps to keep a symptom diary and ask directly whether endometriosis could be the cause.
SHELY Care
Track pain, bleeding, and how each day affects you — a clear cyclical record is powerful evidence to bring to your doctor and shorten the road to diagnosis.
Symptom Checker
Describe your pain pattern to understand whether it points to endometriosis and what to raise with a clinician.
SHELY Varsity
Honest guides on living with endometriosis — pain relief, hormonal and surgical options, fertility, and self-advocacy in appointments.
Symptoms
- Severe period pain that interferes with daily life (dysmenorrhoea)
- Chronic pelvic pain, sometimes between periods
- Pain during or after sex (deep dyspareunia)
- Pain when passing urine or stool, especially during your period
- Heavy or irregular menstrual bleeding
- Bloating or a swollen, tender abdomen ('endo belly')
- Fatigue, particularly around your period
- Difficulty getting pregnant
- Pain that often starts days before bleeding and eases after it ends
Causes
- Retrograde menstruation — period blood flowing backward through the tubes into the pelvis
- Cells outside the uterus transforming into endometrial-like tissue
- Genetics — endometriosis often runs in families
- Immune system differences that fail to clear the misplaced tissue
- Hormonal (oestrogen) sensitivity that drives the tissue to grow
- The exact cause isn't fully understood and is likely a mix of these factors
Types
Superficial peritoneal endometriosis
The most common and mildest form — small deposits on the lining of the pelvis (peritoneum).
Ovarian endometrioma ('chocolate cyst')
Fluid-filled cysts on the ovaries containing old blood, which can affect ovarian function and fertility.
Deep infiltrating endometriosis (DIE)
Tissue that grows deeper into pelvic organs such as the bowel, bladder, or the ligaments behind the uterus, often causing the most severe pain.
Adenomyosis (related condition)
When endometrial-like tissue grows into the muscular wall of the uterus itself, causing heavy, painful periods; it often coexists with endometriosis.
When to seek care
See a doctor if period pain regularly stops you from going to work, school, or daily activities, if you have pain during sex or when going to the toilet, or if you've been trying to conceive without success. Don't wait for the pain to become unbearable — endometriosis is often dismissed as 'normal' bad periods, so it helps to keep a symptom diary and ask directly whether endometriosis could be the cause.
How SHELY helps
SHELY Care
Track pain, bleeding, and how each day affects you — a clear cyclical record is powerful evidence to bring to your doctor and shorten the road to diagnosis.
Symptom Checker
Describe your pain pattern to understand whether it points to endometriosis and what to raise with a clinician.
SHELY Varsity
Honest guides on living with endometriosis — pain relief, hormonal and surgical options, fertility, and self-advocacy in appointments.
Frequently asked
Why does endometriosis take so long to diagnose?
Severe period pain is too often treated as normal, and symptoms overlap with other conditions. On average it can take several years and more than one doctor. Keeping a detailed symptom diary and asking directly about endometriosis can help speed things up.
Can endometriosis be cured?
There's no cure yet, but it's manageable. Pain relief, hormonal treatments to quieten the tissue, and keyhole (laparoscopic) surgery to remove deposits can all help significantly. The right plan depends on your symptoms and whether you're trying to conceive.
Does endometriosis mean I can't have children?
Not necessarily. Endometriosis can make conceiving harder, but many women with it have children, sometimes with medical or fertility support. If pregnancy is a goal, raise it early so it shapes your treatment choices.
Is the amount of pain a sign of how severe it is?
Surprisingly, no. Someone with extensive endometriosis may feel little, while a small amount of tissue can cause intense pain. Your pain is valid regardless of what a scan shows — and worth investigating.
✔ Written from established medical guidance — independent clinical review in progress
This guide is for general education and does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your health. In an emergency or crisis, see our crisis support resources.