Endometriosis is a chronic condition in which tissue similar to the uterine lining grows outside the uterus. It can cause significant pelvic pain, heavy periods, painful sex, bowel or bladder pain, bloating, fatigue, and sometimes infertility. It affects about 1 in 10 people of reproductive age worldwide. There’s no single blood test that proves someone has endometriosis, but smart use of lab tests can help rule out look-alike conditions, document complications (like iron-deficiency anemia), and set baselines before medical or surgical treatment—and then monitor recovery afterwards.
Quick truth: Most guidelines support diagnosing and treating endometriosis based on symptoms and imaging, reserving surgery for select situations—so labs are supportive, not definitive.
Pelvic pain is one of the hallmark symptoms of endometriosis — This lifestyle image represents the daily impact of endometriosis and underscores the importance of early diagnosis and targeted lab testing.
What Is Endometriosis?
Endometriosis is a chronic, inflammatory condition in which tissue similar to the lining of the uterus (endometrium) grows outside the uterine cavity. These misplaced tissue deposits—often called endometrial-like implants or lesions—respond to hormonal changes just like the uterine lining: they thicken, break down, and bleed during each menstrual cycle. But because this tissue is outside the uterus, it has no natural way to exit the body. The trapped blood and inflammation can cause scarring, adhesions, cyst formation, and significant pain.
Where It Can Occur
Endometriosis most commonly affects the pelvic region, but lesions can appear in:
Ovaries – often forming endometriomas (“chocolate cysts”).
Peritoneum – the tissue lining the abdominal cavity.
Uterosacral Ligaments – strong support structures for the uterus.
Rectovaginal Septum – tissue between rectum and vagina.
Bladder or Bowel Surface – less common, but can cause urinary or GI symptoms.
Rare cases involve distant sites like the diaphragm or lungs.
Hormones & Immune Factors
Endometriosis is estrogen-dependent, meaning estrogen fuels lesion growth. Many patients also have increased inflammation and altered immune function, which can help lesions survive and cause nerve growth into affected areas—amplifying pain.
Common Symptoms
Symptoms range from mild to severe and may include:
Pelvic pain before/during periods (dysmenorrhea)
Pain during sex (dyspareunia)
Pain with bowel movements or urination
Heavy or irregular periods
Chronic pelvic pain
Infertility
Bloating, fatigue, low back pain
Potential Complications
Infertility (affects up to 30–50% of patients)
Chronic pelvic pain
Ovarian cyst rupture or torsion
Scar tissue binding organs
Mental health effects (anxiety, depression)
Diagnosis
Diagnosis is based on symptoms, pelvic exam, and imaging (ultrasound, MRI). Laparoscopy—a minimally invasive surgery—is the gold standard for confirmation. While no lab test can diagnose endometriosis, labs help:
Common pelvic sites for endometriosis lesions — This anatomical diagram helps patients visualize where endometriosis can develop and how it relates to pelvic organs.
Why There’s No Definitive Cure
Endometriosis is a chronic, estrogen-dependent condition with a tendency to recur. Even after surgical removal of visible lesions, microscopic disease can remain, and new lesions can form—especially if menstrual cycles continue. Because the condition is hormonally influenced, it can be suppressed but not permanently “eradicated” without also eliminating the hormonal cycles that drive it.
Treatment Approaches
1. Medical Therapy
Hormonal suppression (continuous combined oral contraceptives, progestins, GnRH agonists/antagonists, or LNG-IUS) can significantly reduce pain and slow lesion growth.
These treatments are usually long-term and work by reducing estrogen exposure to the implants.
2. Surgical Management
Laparoscopic excision or ablation can remove visible lesions and restore anatomy.
Particularly effective for ovarian endometriomas and deep infiltrating endometriosis.
Recurrence rates can be lowered when surgery is followed by hormonal suppression (if pregnancy is not the goal).
3. Definitive Surgery
Hysterectomy with or without oophorectomy can relieve symptoms in severe cases for those who have completed childbearing.
Even then, some patients experience residual pain if microscopic implants remain.
Symptom & Recurrence Control
Post-surgery maintenance with hormonal suppression can keep symptoms at bay for years.
Lifestyle and supportive therapies—pelvic floor physical therapy, anti-inflammatory diet, stress management—can help with pain control and improve well-being.
Lab tests such as CBC, Ferritin, AMH, and CRP support ongoing monitoring for complications or treatment effects.
Signs & Symptoms of Endometriosis
Common symptoms
Period pain that interferes with school, work, or daily life (dysmenorrhea)
Chronic pelvic pain (with or without periods)
Pain with sex (dyspareunia), bowel movements, or urination
Heavy menstrual bleeding (can lead to iron‑deficiency anemia)
Bloating, nausea, fatigue
Difficulty getting pregnant
When symptoms suggest complications
Heavy bleeding → fatigue, pallor, shortness of breath (possible anemia)
Severe pain or sudden worsening → possible endometrioma (“chocolate cyst”), ovarian torsion, or other urgent issues
Fertility goals → planning labs that inform ovarian reserve and treatment choices
Understanding the Stages of Endometriosis
Endometriosis is typically classified into four stages—Minimal, Mild, Moderate, and Severe—using the Revised American Society for Reproductive Medicine (rASRM) system. Staging is determined during laparoscopy by scoring the number, depth, and location of lesions, the presence and size of ovarian cysts (endometriomas), and the extent of scar tissue (adhesions).
Note: The stage reflects the extent of visible disease, not the intensity of symptoms. Many women with minimal disease have severe pain, while others with extensive disease may have mild or no symptoms.
EndometriosisStage I — Minimal
Findings: A few small, superficial implants on the peritoneum or ovaries.
Adhesions: None or minimal.
Symptoms: May range from none to severe.
Clinical Note: Even minimal lesions can cause significant pain or infertility.
EndometriosisStage II — Mild
Findings: More implants than Stage I, some slightly deeper.
Adhesions: Minimal or absent.
Symptoms: Painful periods (dysmenorrhea), pelvic discomfort, and/or pain during sex (dyspareunia).
Clinical Note: Fertility may start to be affected, particularly if lesions are close to reproductive structures.
Stage III — Moderate
Findings: Many deep implants, small endometriomas on one or both ovaries.
Adhesions: More extensive, possibly causing distortion of pelvic anatomy.
Symptoms: Persistent pelvic pain, possible bowel/bladder symptoms, higher infertility risk.
Clinical Note: Surgical treatment often aims to remove cysts, release adhesions, and restore normal pelvic anatomy.
EndometriosisStage IV — Severe
Findings: Numerous deep implants, large endometriomas, and widespread adhesions.
Adhesions: May involve the uterus, fallopian tubes, ovaries, bladder, bowel, or ureters.
Clinical Note: Complex surgery may require a multidisciplinary team (gynecology, colorectal, urology).
Alternative Classification Systems
While rASRM is most common, some specialists use the Enzian classification to describe deep infiltrating endometriosis (DIE), which rASRM doesn’t capture well. The Enzian system details the exact location, depth, and organ involvement, which can be useful for complex cases. Reference: PubMed PMID 28709619
Pre-Surgical Staging With Imaging
Advanced imaging, such as MRI and high-resolution transvaginal ultrasound, can sometimes predict severity and map lesion locations before surgery. This is especially helpful for detecting deep lesions and planning surgical strategy. Reference: PubMed PMID 35044862
Fertility Impact by Stage
Stage I–II: Fertility may still be possible naturally, though subtle changes in pelvic environment can affect conception.
Stage III–IV: Higher likelihood of needing fertility treatments such as IVF. See also:AMH Test for Ovarian Reserve for fertility planning.
Symptom-Stage Mismatch
Stage does not predict pain intensity. Nerve involvement, inflammatory activity, and lesion location often drive symptoms more than lesion size or number.
Surgical Complexity
Lower stages: Typically less complex and shorter procedures.
Higher stages: May require longer operating time, advanced surgical skills, and multidisciplinary teams if organs beyond the reproductive system are involved.
Post-Stage Treatment Approaches
Stage I–II: Often managed with hormonal suppression to prevent progression.
Stage III–IV: Combination of surgical excision, hormonal suppression, and fertility counseling if pregnancy is desired.
Recurrence Risk
Recurrence can occur at any stage. Risk is higher if lesions are incompletely excised or if no post-op hormonal therapy is used when pregnancy is not the goal.
Endometriosis Stages at a Glance
Stage
Lesion Characteristics
Adhesions / Scar Tissue
Common Symptoms
Fertility Impact
Typical Treatment Approaches
Stage I — Minimal
Few small, superficial implants on peritoneum or ovaries
None or minimal
Painful periods (dysmenorrhea), pelvic discomfort, may be asymptomatic
Fertility generally preserved, but subtle pelvic changes may affect conception
Dysmenorrhea, pelvic pain, pain with sex (dyspareunia)
Slightly increased infertility risk
Hormonal suppression, NSAIDs, surgical removal if symptomatic or fertility affected
Stage III — Moderate
Many deep implants; small ovarian cysts (endometriomas) on one/both ovaries
More significant adhesions, may distort pelvic structures
Chronic pelvic pain, bowel or bladder discomfort, heavier menstrual bleeding
Higher infertility risk; may need assisted reproductive technologies (ART)
Laparoscopic excision of lesions/cysts, adhesion removal, hormonal suppression post-surgery
Stage IV — Severe
Numerous deep implants; large endometriomas; widespread lesions
Extensive adhesions, often binding organs together; possible involvement of bladder, bowel, ureters
Severe pelvic pain, GI or urinary symptoms, heavy menstrual bleeding
Marked infertility risk; ART often required
Complex multidisciplinary surgery, hormonal suppression if not seeking pregnancy, pain management, pelvic floor therapy
How Lab Tests Help with Endometriosis
Rule out other causes of pelvic pain, heavy bleeding, or irregular cycles (infection, thyroid issues, bleeding disorders).
Document complications (e.g., anemia from heavy periods, systemic inflammation).
Establish pre‑op baselines and ensure safety for anesthesia and surgery.
Track recovery and guide long‑term management (e.g., anemia resolution, ovarian reserve after endometrioma surgery).
Guideline snapshot: Blood biomarkers like CA‑125 are not recommended for diagnosing endometriosis. Imaging (transvaginal ultrasound or MRI) is preferred to evaluate ovarian endometriomas and deep disease; laparoscopy is not mandatory to start treatment.
Individual Test Breakdowns (with direct ordering links)
What it is: A tumor‑associated glycoprotein; can be elevated in endometriosis and many other conditions.
What it measures: Serum CA‑125 level.
Why it matters:Not specific to endometriosis and not recommended to diagnose the disease; may be considered if a clinician already found an ovarian mass and wants an adjunct data point, or to trend only if it was elevated previously.
How it helps patients: Limited role; discuss with your clinician.
Order:CA‑125 Test Guideline note: ESHRE does not recommend serum biomarkers (including CA‑125) for diagnosis. eshre.eu
Anemia & Nutritional Impact from Heavy Periods
Complete Blood Count (CBC)
What it is: A core hematology panel.
What it measures: Hemoglobin/hematocrit, red and white blood cells, platelets.
Why it matters: Heavy menstrual bleeding can cause or worsen iron‑deficiency anemia—CBC shows low hemoglobin/hematocrit and microcytosis.
How it helps patients: Baseline if heavy bleeding; recheck 4–8 weeks after therapy or surgery.
What it measures: Relative quantity of remaining follicles.
Why it matters:Endometrioma surgery (cystectomy) can lower AMH for months; partial recovery at ~12 months is possible. Discuss timing with your clinician if you’re planning pregnancy or egg freezing.
How it helps patients: Baseline before ovarian surgery; recheck 3–12 months post‑op to understand ovarian reserve trajectory.
Order:AMH Test (Female) Evidence: AMH declines significantly after endometrioma cystectomy, with varying recovery by 12 months.
FSH and LH
What they are: Pituitary gonadotropins.
Why they matter: Help characterize cycle dynamics or potential ovulatory dysfunction when cycles are irregular.
What it is: Measures human chorionic gonadotropin.
Why it matters:Required before many imaging tests or surgeries; also essential when pelvic pain and a missed period raise concern for pregnancy or ectopic pregnancy.
There isn’t a single “endometriosis test.” Most results help rule out other causes, track complications (like anemia), or monitor your status. Oxford Academic
Patterns matter:
CBC/Ferritin: Low hemoglobin or ferritin confirms anemia from heavy bleeding; values should rise after effective treatment or surgery. ACOG
CRP/ESR: Often normal in endometriosis; a new rise after surgery warrants evaluation for infection or another inflammatory process.
CA‑125: Not for diagnosis; if your CA‑125 was elevated before treatment, your clinician may decide whether trending adds value for you. eshre.eu
AMH: Expect a drop after ovarian endometrioma surgery; some recovery by ~12 months is common. Timing your fertility decisions around these trends can be helpful. PMC
Typical retesting cadence (individualized by your clinician):
CBC/Ferritin: at baseline; again 4–8 weeks after therapy/surgery; then every 3–6 months if heavy bleeding persists.
CRP/ESR: only if clinically indicated (e.g., suspected post‑op complication).
AMH: baseline before ovarian surgery or IVF planning; repeat ~3–6 months, and again at 12 months post‑op if fertility is a goal.
Thyroid/Prolactin: baseline if cycles are irregular or fertility is a goal; repeat as advised.
hCG: prior to procedures and as clinically indicated.
When to Talk to Your Doctor—Right Away
Severe, worsening pelvic pain, fever, vomiting, fainting, or pain with a positive pregnancy test
Heavy bleeding soaking through pads/tampons hourly for several hours, or symptoms of anemia (shortness of breath, chest pain, dizziness)
Post‑op red flags: fever, foul discharge, uncontrolled pain, rapidly rising CRP/ESR, or falling hemoglobin
Fertility planning: if you’re considering pregnancy, IUI/IVF, or endometrioma surgery, discuss AMH and timingfirst.
Quick truth: Most guidelines support diagnosing and treating endometriosis based on symptoms and imaging, reserving surgery for select situations—so labs are supportive, not definitive.
Post Endometriosis Surgery
Surgery—whether conservative excision/ablation or removal of an endometrioma—can be a turning point. The goal after surgery is twofold: (1) help you feel better now and (2) reduce the chance that pain or cysts come roaring back. There isn’t a single lab that “checks for endometriosis recurrence,” but a smart follow-up plan uses targeted labs to confirm healing, watch for potential complications, and support fertility planning when that’s on your roadmap.
Post-Op Lab Roadmap
If you dealt with heavy periods or low iron levels before surgery…
By combining symptoms, imaging, and targeted labs, you and your clinician can better navigate diagnosis, surgery planning, and long-term management. Whether you’re checking for anemia, assessing ovarian reserve, or monitoring post-operative healing, Ulta Lab Tests makes it easy to order affordable, physician-reviewed labs online—no insurance or doctor’s visit required.
Frequently Asked Questions
1. Understanding Endometriosis Lab Testing
Q: Is there a blood test that can diagnose endometriosis? A: No single blood test can definitively diagnose endometriosis. Biomarkers such as CA-125 can be elevated in endometriosis but also in other conditions, so they are not specific. Diagnosis is usually based on symptoms, imaging, and sometimes laparoscopy. Reference: PubMed PMID 30799259, NIH/NICHD Endometriosis Fact Sheet.
Q: Which lab tests are most useful for women with endometriosis symptoms? A: Lab tests can help rule out other causes of pelvic pain, identify anemia from heavy menstrual bleeding, and assess fertility. Commonly used tests include:
CRP or ESR for inflammation Reference: PubMed PMID 33285437, CDC Heavy Menstrual Bleeding Guidelines.
2. Anemia and Nutritional Testing
Q: How can heavy periods from endometriosis cause anemia? A: Excessive bleeding can lower iron levels, leading to iron-deficiency anemia, which can cause fatigue, dizziness, and weakness. Blood tests like CBC and ferritin measure hemoglobin and iron stores to guide treatment. Reference: CDC Iron-Deficiency Anemia Facts, PubMed PMID 34818372.
3. Fertility and Hormone Panels
Q: Why is AMH testing important for women with endometriosis? A: The Anti-Müllerian Hormone test measures ovarian reserve, which may be reduced in women with ovarian endometriomas or after surgery. AMH helps in fertility planning. Reference: PubMed PMID 30807861, NIH Reproductive Health Data.
Q: What hormone tests may be ordered if cycles are irregular? A: Clinicians may check FSH, LH, estradiol, progesterone, prolactin, and TSH to evaluate reproductive and thyroid function. Reference: PubMed PMID 28642174.
4. Inflammation and Monitoring
Q: Can CRP or ESR detect endometriosis? A: These inflammation markers are non-specific and not diagnostic for endometriosis but may be ordered to evaluate other conditions or postoperative complications. Reference: PubMed PMID 32876594.
