Painful Periods: Is This Normal or Could It Be Endometriosis?

What is normal period pain?

Menstrual cramps (dysmenorrhea) are caused by prostaglandins — hormone-like compounds that trigger the uterus to contract to shed its lining. Mild to moderate cramping in the first one to two days of a period is common and considered a normal physiological response.

Primary dysmenorrhea refers to cramps that occur in the absence of an underlying condition. It typically: - Begins 6–12 hours before or at the start of flow - Peaks in the first one to two days - Responds to over-the-counter NSAIDs (like ibuprofen) or heat - Does not worsen progressively over the years

Secondary dysmenorrhea refers to period pain caused by an underlying condition — most commonly endometriosis, fibroids, or adenomyosis. This type often worsens over time and may not respond fully to standard pain relief.

What is endometriosis?

Endometriosis is a condition in which tissue similar to the uterine lining (endometrium) grows outside the uterus — on the ovaries, fallopian tubes, pelvic walls, bowel, or bladder. This tissue responds to hormonal cycles just like the lining inside the uterus: it thickens, breaks down, and bleeds — but has nowhere to go. This causes inflammation, scar tissue (adhesions), and pain 1Ref 1American College of Obstetricians and Gynecologists (2010).Management of Endometriosis: ACOG Practice Bulletin, Number 114 (Reaffirmed 2022).Endometriosis definition, prevalence (~1 in 10), diagnostic approach (laparoscopy as gold standard, empirical treatment), and treatment options including hormonal therapy and surgery.

Endometriosis is estimated to affect roughly 1 in 10 people with a uterus of reproductive age, though many go undiagnosed for years because period pain is often normalized or undertreated 1Ref 1American College of Obstetricians and Gynecologists (2010).Management of Endometriosis: ACOG Practice Bulletin, Number 114 (Reaffirmed 2022).Endometriosis definition, prevalence (~1 in 10), diagnostic approach (laparoscopy as gold standard, empirical treatment), and treatment options including hormonal therapy and surgery.

How do I know if my period pain is 'too much'?

Pain that meets any of the following descriptions warrants evaluation by a gynecologist 1Ref 1American College of Obstetricians and Gynecologists (2010).Management of Endometriosis: ACOG Practice Bulletin, Number 114 (Reaffirmed 2022).Endometriosis definition, prevalence (~1 in 10), diagnostic approach (laparoscopy as gold standard, empirical treatment), and treatment options including hormonal therapy and surgery2Ref 2American College of Obstetricians and Gynecologists (2019).Screening and Management of Bleeding Disorders in Adolescents With Heavy Menstrual Bleeding: ACOG Committee Opinion, Number 785.Heavy menstrual bleeding (soaking through protection, passing large clots) as a feature accompanying painful periods that warrants clinical evaluation:

• Requires you to miss school, work, or planned activities on a regular basis
• Is not adequately controlled by over-the-counter NSAIDs taken on schedule (before cramping peaks)
• Gets progressively worse from one year to the next — rather than staying the same or improving
• Occurs outside of menstruation — mid-cycle pelvic pain, pain during or after sex (deep dyspareunia), pain with bowel movements or urination around your period
• Is accompanied by heavy bleeding — soaking through protection, passing large clots 2Ref 2American College of Obstetricians and Gynecologists (2019).Screening and Management of Bleeding Disorders in Adolescents With Heavy Menstrual Bleeding: ACOG Committee Opinion, Number 785.Heavy menstrual bleeding (soaking through protection, passing large clots) as a feature accompanying painful periods that warrants clinical evaluation
• Is accompanied by bloating or GI symptoms that reliably worsen with periods

Pain that has always been severe since your first period can also be endometriosis — the condition can be present from the very first menstrual cycles.

What other conditions cause period pain?

Conditions that can cause pelvic pain similar to or overlapping with endometriosis include:

Adenomyosis — when endometrial tissue grows into the muscle wall of the uterus. It often causes heavy, painful periods and a tender, enlarged uterus.

Fibroids — particularly submucosal fibroids, which can worsen cramping and bleeding.

Pelvic inflammatory disease (PID) — infection involving the uterus, tubes, or ovaries. Pelvic pain accompanied by fever, unusual discharge, or pain outside of periods should prompt urgent evaluation.

A gynecologist uses history, exam, imaging (ultrasound, and sometimes MRI), and sometimes diagnostic surgery to distinguish between these causes.

How is endometriosis diagnosed?

Definitive diagnosis of endometriosis has historically required laparoscopy — a minimally invasive surgical procedure in which a camera is used to directly visualize and biopsy lesions 1Ref 1American College of Obstetricians and Gynecologists (2010).Management of Endometriosis: ACOG Practice Bulletin, Number 114 (Reaffirmed 2022).Endometriosis definition, prevalence (~1 in 10), diagnostic approach (laparoscopy as gold standard, empirical treatment), and treatment options including hormonal therapy and surgery. However, ACOG's 2026 clinical guidance on the diagnosis of endometriosis acknowledges that many gynecologists begin treatment empirically based on clinical presentation — symptoms, examination, and imaging — without requiring surgery first, particularly when the presentation is classic.

An ultrasound can identify some types of endometriosis (particularly endometriomas on the ovaries) but misses superficial peritoneal lesions. MRI can provide additional detail. A thorough clinical history focused on the characteristic pain pattern is central to the diagnostic evaluation.

What treatment options exist?

Endometriosis is a chronic condition that is managed, not cured. Treatment aims to reduce pain and, where relevant, preserve fertility 1Ref 1American College of Obstetricians and Gynecologists (2010).Management of Endometriosis: ACOG Practice Bulletin, Number 114 (Reaffirmed 2022).Endometriosis definition, prevalence (~1 in 10), diagnostic approach (laparoscopy as gold standard, empirical treatment), and treatment options including hormonal therapy and surgery:

NSAIDs — taken on a scheduled basis (starting before pain peaks) to reduce prostaglandin-driven cramping. More effective when begun 1–2 days before expected flow.

Hormonal therapy — a wide range of hormonal options (including certain pills, the hormonal IUD, progestins, and GnRH agonists or antagonists) can suppress the cycle and reduce symptoms. The right choice depends on severity, fertility goals, and individual tolerance of side effects.

Surgery — laparoscopic excision or ablation of endometriosis lesions can provide symptom relief and improve fertility in some cases, though endometriosis can recur after surgery.

Management is individualized and often requires a gynecologist with experience in endometriosis care.