📋 Key Information Summary
- Always exclude ectopic pregnancy first — perform a urine or serum β-hCG in any woman of reproductive age presenting with lower abdominal or pelvic pain, regardless of contraceptive history or reported menstrual pattern.
- Surgical emergencies to consider: ruptured ectopic pregnancy, ovarian torsion, appendicitis, and ruptured ovarian cyst — all require urgent imaging and surgical consultation.
- Ectopic pregnancy affects approximately 1 in 80 pregnancies in Australia; risk factors include previous ectopic, prior tubal surgery, PID history, IUD use, and assisted reproduction. Transvaginal ultrasound (TVS) with β-hCG ≥ 1,500 IU/L is the standard diagnostic pathway.
- Haemodynamically unstable patient with positive β-hCG: assume ruptured ectopic until proven otherwise — activate surgical emergency pathway immediately; do not delay for imaging.
- Pelvic inflammatory disease (PID) is frequently underdiagnosed; empirical treatment should be initiated in any sexually active woman with pelvic pain, cervical motion tenderness, and/or adnexal tenderness when no other cause is identified. Treat with ceftriaxone 500 mg IM stat plus doxycycline 100 mg PO BD for 14 days ± metronidazole 400 mg PO BD for 14 days.
- Chlamydia trachomatis remains the most common notifiable sexually transmitted infection in Australia, with highest rates in young Aboriginal and Torres Strait Islander women aged 15–24 years.
- Endometriosis affects an estimated 1 in 9 Australian women and takes an average of 6–8 years from symptom onset to diagnosis. Suspect in chronic pelvic pain, dysmenorrhoea, dyspareunia, and subfertility.
- Ovarian torsion is a surgical emergency — sudden onset severe unilateral pelvic pain with nausea/vomiting; Doppler ultrasound may show absent or reduced arterial flow but normal Doppler does not exclude torsion.
- Functional ovarian cysts (follicular, corpus luteum) are common and usually self-resolving; haemorrhagic corpus luteum cysts can mimic ectopic pregnancy or appendicitis.
- The "surgical sieve" approach — systematically consider gynaecological, gastrointestinal (appendicitis, diverticulitis), urological (UTI, renal colic), and musculoskeletal causes in every patient.
- Abdominal aortic aneurysm must be considered in women ≥ 65 years with lower abdominal pain; Australian screening is less established than in men but clinical vigilance is essential.
- Aboriginal and Torres Strait Islander women have significantly higher rates of PID, chlamydia, and later presentations of ectopic pregnancy. Culturally safe care, point-of-care testing in remote communities, and linkage to sexual health services are critical.
Introduction & Australian Epidemiology
Lower abdominal and pelvic pain is one of the most common presenting complaints in Australian general practice and emergency departments, accounting for an estimated 2–3% of all primary care consultations in women of reproductive age. The differential diagnosis is broad, spanning gynaecological, gastrointestinal, urological, and musculoskeletal aetiologies. A systematic, evidence-based approach is essential to avoid the twin pitfalls of delayed diagnosis of serious conditions and unnecessary surgical intervention.
In Australia, the most commonly identified causes of acute pelvic pain in women presenting to emergency departments are:
- Functional ovarian cysts — the most frequent cause, accounting for up to 30% of presentations
- Urinary tract infections — responsible for approximately 15–20% of lower abdominal pain in women
- Pelvic inflammatory disease — estimated 30,000–50,000 cases annually in Australia, though likely significantly underreported
- Ectopic pregnancy — complicates 1–2% of all pregnancies nationally; rupture accounts for approximately 4% of maternal deaths in Australia
- Endometriosis — affects an estimated 830,000 Australian women; the economic burden exceeds .7 billion annually (AIHW, 2023)
Key Australian-specific considerations include significantly higher rates of sexually transmitted infections and PID in Aboriginal and Torres Strait Islander communities, geographic barriers to specialist gynaecological and surgical services in rural and remote areas, and the increasing role of point-of-care testing and telehealth in regional settings. The Australian Commission on Safety and Quality in Health Care (ACSQHC) emphasises structured clinical handover and timely escalation of care for patients with acute abdominal pain.
Clinical Pearl: In any woman of reproductive age presenting with lower abdominal pain, the first test should be a pregnancy test (urine β-hCG or serum β-hCG). This single investigation cannot be omitted, regardless of the patient's stated contraceptive use, sexual history, or denial of pregnancy possibility. Ruptured ectopic pregnancy remains a leading cause of preventable maternal mortality in Australia.
Diagnostic Model & Serious Disorders
The diagnostic approach to lower abdominal and pelvic pain in women requires a structured clinical framework that balances thoroughness with urgency. The following stepwise model is recommended for Australian primary care and emergency settings.
Step 1: Immediate Risk Stratification
Assess haemodynamic stability, peritoneal signs, and pregnancy status within the first 5 minutes of assessment.
1
Haemodynamic Assessment
Tachycardia, hypotension, pallor, diaphoresis — if present, activate emergency surgical pathway. Consider ruptured ectopic, ovarian torsion, or intra-abdominal haemorrhage.
2
Pregnancy Test
Urine β-hCG (point-of-care) in all women of reproductive age. If positive → urgent TVS. If negative but clinical suspicion → serum β-hCG (sensitivity to 5 IU/L).
3
Peritoneal Signs
Guarding, rigidity, rebound tenderness, absent bowel sounds. If present → surgical consultation before further investigation.
4
Fever + Pelvic Pain
Temperature ≥ 38°C with pelvic pain raises concern for PID, tubo-ovarian abscess, or septic abortion. Initiate empirical antibiotics.
Step 2: Systematic Differential Diagnosis
| Category | Condition | Key Distinguishing Features | Urgency |
|---|---|---|---|
| Gynaecological | Ectopic pregnancy | Positive β-hCG, unilateral pain, vaginal bleeding, adnexal mass on TVS | Emergency |
| Ovarian torsion | Sudden onset, severe unilateral pain, nausea/vomiting, ovarian mass | Emergency | |
| PID / TOA | Bilateral pelvic pain, cervical motion tenderness, fever, vaginal discharge | Urgent | |
| Ruptured ovarian cyst | Acute onset mid-cycle pain, may have peritoneal irritation, β-hCG negative | Urgent | |
| Endometriosis | Chronic cyclical pain, dysmenorrhoea, dyspareunia, dyschezia | Routine | |
| Gastrointestinal | Appendicitis | Peri-umbilical → RLQ pain, anorexia, nausea, McBurney's point tenderness | Emergency |
| Diverticulitis | LLQ pain, fever, raised WCC/CRP, typically > 40 years | Urgent | |
| IBS flare | Chronic, bloating, altered bowel habit, no red flags, relief with defaecation | Routine | |
| Urological | UTI / pyelonephritis | Dysuria, frequency, urgency, suprapubic/flank pain, positive dipstick | Urgent |
| Renal colic | Colicky flank to groin pain, haematuria, restlessness | Urgent | |
| Other | Abdominal aortic aneurysm | Pulsatile mass, hypotension, back pain — consider in women ≥ 65 years | Emergency |
Step 3: Red-Flag Features Requiring Immediate Escalation
Immediate surgical/obstetric consultation required if any of the following are present:
- Haemodynamic instability (SBP < 90 mmHg, HR > 110 bpm)
- Positive β-hCG with acute pelvic pain and no intrauterine pregnancy on TVS
- Peritoneal signs (guarding, rigidity, rebound)
- Sudden onset severe unilateral pain with nausea/vomiting (ovarian torsion)
- Signs of sepsis: temperature > 38.5°C, tachycardia, hypotension, altered mental state
- Free fluid in the pouch of Douglas on ultrasound in the context of positive β-hCG
Step 4: Investigations in Primary Care
Essential
Urine β-hCG (point-of-care)
All women of reproductive age — MBS item 66500 (pregnancy test). Perform before any imaging. Sensitivity > 99% for qualitative urine tests at 25 IU/L threshold.
Essential
Urine microscopy, culture & sensitivity (MCS)
MBS item 69310. Rule out UTI as a common mimic of pelvic pathology. Midstream urine preferred.
Available
FBC, CRP, serum β-hCG
MBS items 65070, 65141, 66497. Serum β-hCG quantitative if ectopic suspected. CRP for inflammatory markers. FBC for anaemia (haemorrhage) or leukocytosis (infection).
Available
Nucleic acid amplification test (NAAT) for chlamydia/gonorrhoea
MBS item 69340. First-void urine or endocervical swab. Essential if PID or STI suspected. Results typically 1–3 working days; point-of-care NAAT available in some services.
Available
Transvaginal ultrasound (TVS)
MBS item 55610. Gold standard for pelvic pathology — ectopic pregnancy, ovarian cysts, torsion, hydrosalpinx, TOA. Should be performed urgently if β-hCG positive or if clinical suspicion of surgical emergency.
Referral
CT abdomen/pelvis
MBS item 56000 series. For suspected appendicitis, diverticulitis, or AAA. Not first-line for gynaecological causes (TVS preferred).
Specialist
Diagnostic laparoscopy
Definitive for endometriosis, and diagnostic/therapeutic in ovarian torsion. Requires gynaecology or general surgery referral.
Ectopic Pregnancy — Diagnosis & Management
Ectopic pregnancy is the implantation of a fertilised ovum outside the endometrial cavity, most commonly in the fallopian tube (97%). It remains a significant cause of maternal morbidity and mortality in Australia, accounting for approximately 4% of maternal deaths nationally. Early diagnosis through the systematic use of β-hCG and transvaginal ultrasound has improved outcomes, but delayed presentation — particularly in rural, remote, and Aboriginal and Torres Strait Islander communities — continues to result in preventable complications.
Australian Epidemiology
- Incidence: approximately 1–2% of all pregnancies in Australia
- Leading cause of first-trimester maternal mortality
- Rates are higher in Aboriginal and Torres Strait Islander women, likely related to higher rates of PID and delayed access to care
- Incidence has increased over the past two decades due to rising rates of tubal surgery, assisted reproductive technology (ART), and previous PID
Risk Factors
| Risk Factor | Relative Risk (Approximate) |
|---|---|
| Previous ectopic pregnancy | 8–10× (after 1 ectopic), 25–30× (after ≥ 2 ectopics) |
| Previous tubal surgery (including tubal ligation) | 4–8× |
| Documented tubal pathology / PID history | 3–5× |
| Current IUD in situ (copper or levonorgestrel) | RR < 1 overall (IUDs reduce all pregnancies), but if pregnant with IUD, ectopic proportion is higher |
| Assisted reproductive technology (IVF/ICSI) | 2–4× |
| Cigarette smoking | 1.5–3× (dose-dependent) |
| Endometriosis | 1.5–2× |
| Maternal age ≥ 35 years | 1.5–3× |
Clinical Presentation
Classic triad: unilateral pelvic pain + vaginal bleeding + amenorrhoea, but presentation is highly variable. Up to 50% of patients present with atypical features.
- Unruptured ectopic: mild unilateral pelvic/abdominal pain, light vaginal bleeding or brown discharge, may be asymptomatic
- Ruptured ectopic: sudden severe lower abdominal pain, syncope, shoulder-tip pain (diaphragmatic irritation from intra-abdominal haemorrhage), signs of haemorrhagic shock
- Shoulder-tip pain is a particularly concerning sign indicating significant intra-abdominal blood irritating the diaphragm
Ruptured Ectopic = Surgical Emergency: If a patient is haemodynamically unstable with a positive pregnancy test, proceed directly to emergency laparotomy/laparoscopy. Do NOT delay for formal ultrasound. A bedside point-of-care ultrasound to look for free fluid in the pelvis may be performed simultaneously but must not delay definitive management.
Diagnostic Pathway
1
Urine or Serum β-hCG
Qualitative urine β-hCG (sensitivity at 25 IU/L). If positive → proceed to TVS. If negative and high clinical suspicion → serum quantitative β-hCG (sensitivity at 5 IU/L).
2
Transvaginal Ultrasound (TVS)
TVS is the imaging modality of choice (MBS item 55610). An intrauterine pregnancy (IUP) should be visible when β-hCG ≥ 1,500–2,000 IU/L (discriminatory zone). Absence of IUP with β-hCG above this threshold is suspicious for ectopic.
3
Serial β-hCG
If β-hCG is below the discriminatory zone and TVS is indeterminate: repeat β-hCG in 48 hours. Normal viable IUP: β-hCG rises ≥ 66% over 48 hours. Abnormal rise (< 66%) or plateau → ectopic or non-viable pregnancy likely.
4
Definitive Diagnosis
Extrauterine gestational sac with yolk sac and/or fetal pole is definitive. Adnexal mass with "tubal ring" sign, free fluid in pouch of Douglas, or "empty uterus" with rising β-hCG are highly suggestive.
Management
Stable — Medical
Methotrexate (MTX)
Criteria for MTX: Haemodynamically stable, ectopic < 3.5 cm, no fetal cardiac activity, β-hCG ≤ 5,000 IU/L (some centres ≤ 10,000 IU/L), patient reliable for follow-up.
Dose: Methotrexate 50 mg/m² IM single dose (calculate body surface area). PBS Authority Required.
Follow-up: β-hCG on days 4 and 7. A ≥ 15% fall between day 4 and day 7 indicates success. Continue weekly β-hCG until < 5 IU/L.
Failure: If β-hCG does not fall ≥ 15% by day 7 → second dose MTX or surgical management.
Setting: Gynaecology outpatient with day-stay capability
Stable — Surgical
Laparoscopic Salpingostomy/Salpingectomy
Indications: Failed or contraindicated MTX, ectopic > 3.5 cm, fetal cardiac activity present, patient preference, unreliable follow-up.
Salpingostomy: Linear incision on antimesenteric border of tube, tissue removed, tube left to heal by secondary intention. Risk of persistent trophoblast: 5–15%.
Salpingectomy: Preferred if the tube is significantly damaged, there is a recurrent ectopic in the same tube, or the patient has completed her family.
Rh status: Administer Anti-D immunoglobulin 625 IU (250 µg) IM to all Rh-negative women with ectopic pregnancy (PBS Authority Required).
Setting: Hospital — gynaecology theatre
Unstable
Emergency Laparotomy
Indications: Haemodynamic instability, signs of rupture with significant haemoperitoneum, diagnostic uncertainty with peritonitis.
Management: Resuscitation with IV crystalloid and packed red blood cells (group & crossmatch). Activate massive transfusion protocol if required. Emergency salpingectomy is the standard procedure. Involve general/vascular surgery if there is extensive haemorrhage.
Setting: Emergency — operating theatre, tertiary hospital preferred
Pharmacotherapy Detail
Methotrexate
Methoblastin® · Antifolate antimetabolite
Adult dose
50 mg/m² IM single dose (body surface area calculated from height/weight)
Route
Intramuscular injection
Duration
Single dose; repeat at day 7 if β-hCG decline < 15%
Renal adjustment
Contraindicated if eGFR < 30 mL/min; use with caution if eGFR 30–60 mL/min
Hepatic adjustment
Contraindicated if significant hepatic impairment (bilirubin > 3× ULN)
Key interactions
NSAIDs (↓ clearance), penicillins, folate-containing supplements — avoid concurrent folate
PBS status
✔ PBS Authority Required
Anti-D Immunoglobulin
RhoGAM® · WinRho® · Anti-D immunoglobulin
Indication
Rh-negative women with ectopic pregnancy (ruptured or surgical management)
Adult dose
625 IU (250 µg) IM within 72 hours of event
Route
Intramuscular
Renal / Hepatic
No dose adjustment
PBS status
✔ PBS Authority Required
Counselling After Ectopic Pregnancy
- Recurrence risk: approximately 10–15% after one ectopic pregnancy
- Subsequent intrauterine pregnancy rate: approximately 60–70%
- Advise early dating ultrasound in any future pregnancy (at 6–7 weeks gestation)
- Psychological impact: screen for depression and anxiety; referral to perinatal mental health services or counselling as appropriate
- Contraception: advise reliable contraception for at least 3 months after MTX (due to teratogenicity) and until β-hCG is < 5 IU/L
Pelvic Inflammatory Disease (PID)
Pelvic inflammatory disease (PID) encompasses a spectrum of upper genital tract infections in women, including endometritis, salpingitis, tubo-ovarian abscess (TOA), and pelvic peritonitis. It is most commonly caused by ascending infection from the cervix, with Chlamydia trachomatis and Neisseria gonorrhoeae being the principal aetiological agents. However, PID is frequently polymicrobial, with anaerobes, Mycoplasma genitalium, and other vaginal flora contributing to the disease process.
Australian Epidemiology
- Chlamydia is the most commonly notified STI in Australia, with over 120,000 notifications in 2022 (Australian Government Department of Health)
- Notification rates in Aboriginal and Torres Strait Islander peoples are approximately 3–5 times higher than in non-Indigenous Australians
- Gonorrhoea notifications have increased significantly in recent years, particularly in men who have sex with men (MSM) and in remote Indigenous communities
- PID rates peak in women aged 15–24 years
- Up to 80% of chlamydial infections and 50% of gonococcal infections in women are asymptomatic — many cases of PID develop without a prior recognised STI diagnosis
Clinical Presentation
PID has a wide spectrum of clinical severity, from subclinical/asymptomatic infection to life-threatening tubo-ovarian abscess and pelvic peritonitis. The clinical diagnosis of PID is imprecise — a low threshold for empirical treatment is recommended to prevent long-term sequelae.
| Feature | Sensitivity for PID | Notes |
|---|---|---|
| Lower abdominal/pelvic pain | High (constant) | Bilateral in most cases; may be unilateral |
| Cervical motion tenderness | High (most specific physical sign) | Bimanual examination finding |
| Adnexal tenderness | High | May be unilateral or bilateral |
| Abnormal vaginal/cervical discharge | Moderate | Mucopurulent cervicitis is suggestive |
| Fever > 38°C | Low–moderate | May be absent in mild disease |
| Vaginal bleeding (irregular) | Low–moderate | Post-coital or intermenstrual |
Empirical Treatment Threshold: The CDC (2021) and BASHH guidelines recommend empirical antibiotic treatment for PID in any sexually active woman with pelvic pain, cervical motion tenderness, or adnexal tenderness when no other cause is identified. Waiting for confirmatory test results before initiating treatment increases the risk of long-term complications including tubal factor infertility, chronic pelvic pain, and ectopic pregnancy.
Complications of Untreated PID
- Tubal factor infertility: after one episode of PID, approximately 8–12%; after three episodes, up to 40–60%
- Ectopic pregnancy: 6–10× increased risk
- Chronic pelvic pain: up to 25% of women with PID develop chronic pain
- Tubo-ovarian abscess (TOA): develops in 15–20% of PID episodes; may require surgical drainage
- Fitz-Hugh-Curtis syndrome: perihepatitis causing right upper quadrant pain — occurs in 5–10% of PID cases
Investigations
- NAAT for chlamydia and gonorrhoea (MBS item 69340): first-void urine or endocervical/vaginal swab. Gold standard for diagnosis. Self-collected vaginal swabs are acceptable and improve access in primary care.
- Endocervical swab for microscopy, culture & sensitivity (MBS item 69315): particularly important if gonorrhoea is suspected, for antimicrobial resistance profiling
- Mycoplasma genitalium PCR (MBS item 69401): consider in treatment-refractory or recurrent cases. Testing is available through major Australian pathology providers (Pathology Queensland, NSWHP, Clinipath, etc.)
- Serum β-hCG: always exclude ectopic pregnancy before diagnosing PID
- FBC, CRP, ESR: non-specific but supportive of inflammatory/infective process
- Transvaginal ultrasound: recommended for all cases — may demonstrate thickened fluid-filled tubes (pyosalpinx), tubo-ovarian abscess, free pelvic fluid, or endometrial thickening
- HIV and syphilis serology: all women diagnosed with PID should be screened for other STIs
Treatment
Treatment should be initiated as soon as the clinical diagnosis is suspected, ideally on the same day. Current recommendations follow the Australian STI Management Guidelines (ASHM, 2022 update) and Therapeutic Guidelines (eTG).
Outpatient / Mild–Moderate PID
Ceftriaxone
Rocephin® · Third-generation cephalosporin
Adult dose
500 mg IM stat (single dose) — for persons < 100 kg; 1 g IM stat for ≥ 100 kg
Indication
Coverage of Neisseria gonorrhoeae (dual therapy with doxycycline)
Renal / Hepatic
No adjustment required for single dose
PBS status
✔ PBS General Benefit
Doxycycline
Doryx® · Doxy® · Tetracycline antibiotic
Adult dose
100 mg PO BD for 14 days
Indication
Coverage of Chlamydia trachomatis and Mycoplasma genitalium
Renal adjustment
No adjustment required
Hepatic adjustment
Use with caution in significant hepatic impairment
Key counselling
Take with food and water; avoid lying flat for 30 minutes; avoid concurrent antacids/iron/calcium; photosensitivity — use SPF 50+
PBS status
✔ PBS General Benefit
Metronidazole
Flagyl® · Metrogyl® · Nitroimidazole antibiotic
Adult dose
400 mg PO BD for 14 days
Indication
Coverage of anaerobes (Bacteroides, Prevotella); recommended if TOA suspected, or concurrent bacterial vaginosis
Renal adjustment
No adjustment required
Key counselling
Avoid alcohol — disulfiram-like reaction (nausea, vomiting, flushing)
PBS status
✔ PBS General Benefit
Inpatient / Severe PID (Hospital Admission Indicated)
Admission criteria:
- Diagnostic uncertainty (cannot exclude surgical emergency)
- Suspected or confirmed tubo-ovarian abscess
- Clinical severity: fever > 38.5°C, tachycardia, vomiting, inability to tolerate oral medications
- Pregnancy
- Failed outpatient oral therapy after 48–72 hours
- Social factors: unreliable follow-up, remote location
IV regimen (inpatient):
- Ceftriaxone 1 g IV daily + doxycycline 100 mg PO/IV BD + metronidazole 500 mg IV TDS or 400 mg PO BD
- Continue IV therapy until clinically improved (afebrile for 24–48 hours, tolerating oral intake), then switch to oral completion (total 14 days)
- For severe penicillin allergy: consult infectious diseases — alternative regimens may include azithromycin 500 mg IV daily + metronidazole 500 mg IV TDS
Partner Notification
Partner notification is a critical component of PID management to prevent reinfection and ongoing transmission. All sexual partners from the preceding 6 months (or the most recent partner if longer) should be notified, tested, and treated. Australian state and territory public health legislation mandates partner notification for chlamydia and gonorrhoea. Contact tracing resources: Sexual Health Info Link (1800 451 624) and online partner notification tools (The Drama Downunder, The[inner]).
Follow-Up
- Clinical review at 48–72 hours if outpatient treatment — assess for improvement or need for admission
- Test of cure (NAAT) at 4 weeks post-completion for chlamydia and gonorrhoea — particularly important in pregnancy, if adherence uncertain, or if M. genitalium is detected
- Repeat STI screening at 3 months (recommended, as reinfection rates are high)
Endometriosis & Ovarian Cysts/Torsion
Endometriosis
Endometriosis is defined as the presence of endometrial-like tissue (glands and stroma) outside the uterine cavity. It is a chronic, oestrogen-dependent inflammatory condition affecting an estimated 830,000 Australian women (approximately 1 in 9 women of reproductive age). The disease is associated with chronic pelvic pain, dysmenorrhoea, deep infiltrating endometriosis (DIE), subfertility, and significant impairment of quality of life. The average time from symptom onset to diagnosis in Australia is 6–8 years, reflecting widespread normalisation of menstrual pain and diagnostic delays.
Clinical Features
| Symptom | Prevalence | Notes |
|---|---|---|
| Dysmenorrhoea (cyclical pelvic pain) | ~80% | Progressive, often beginning in adolescence; may not respond to simple analgesia or COCP |
| Deep dyspareunia | ~50% | Particularly suggestive of posterior compartment / rectovaginal disease |
| Chronic pelvic pain (non-cyclical) | ~40–60% | Central sensitisation may perpetuate pain beyond hormonal influence |
| Dyschezia (painful defaecation) | ~25% | Suggests bowel involvement (rectosigmoid endometriosis) |
| Dysuria / cyclical urinary symptoms | ~15% | May indicate bladder endometriosis |
| Subfertility | ~30–50% | Mechanism includes distorted pelvic anatomy, adhesions, inflammatory peritoneal environment |
| Fatigue | ~50% | Often debilitating; may be the predominant complaint |
Diagnostic Approach
1
Clinical Suspicion
Young woman with progressive dysmenorrhoea not responding to oral contraceptive pill (OCP) or NSAIDs, deep dyspareunia, cyclical bowel or bladder symptoms, or subfertility. Family history (first-degree relative: 5–7× risk).
2
Examination
Bimanual examination — may be normal or reveal uterosacral nodularity, fixed retroverted uterus, adnexal mass (endometrioma), or reduced organ mobility. Rectovaginal examination for posterior compartment disease.
3
Imaging
TVS (MBS item 55610): operator-dependent for endometriosis — sensitivity for DIE is ~80% in experienced hands. MRI pelvis (MBS item 63501 series): superior for rectovaginal and bladder endometriosis, and surgical planning. A normal scan does NOT exclude endometriosis.
4
Definitive Diagnosis
Laparoscopy with histological confirmation remains the gold standard. Visual diagnosis alone has a misclassification rate of ~5%. Biopsy of suspicious peritoneal lesions is recommended. Diagnosis should not be delayed pending laparoscopy if empirical hormonal therapy provides adequate symptom relief.
Medical Management of Endometriosis
Combined Oral Contraceptive Pill (COCP)
Levlen ED® · Brenda-35 ED® · Yaz®
Adult dose
Continuous (skip sugar pills) or cyclic use; typical: ethinylestradiol 30 µg / levonorgestrel 150 µg daily
Mechanism
Suppresses ovulation and endometrial proliferation, reduces menstrual flow
PBS status
✔ PBS General Benefit (most brands)
Levonorgestrel IUD (Mirena®)
Mirena® · 52 mg levonorgestrel intrauterine system
Adult dose
52 mg levonorgestrel IUD; effective for up to 5 years (8 years for contraception per PBS, 5 years for endometriosis)
Mechanism
Local progestogenic effect — endometrial atrophy, reduced menstruation
PBS status
✔ PBS General Benefit
Norethisterone
Primolut N® · Noriday® · Progestogen
Adult dose
5 mg PO BD–TDS (range 5–15 mg/day); continuous
Mechanism
Progestogenic suppression of endometriotic implants
Side effects
Breakthrough bleeding, weight gain, acne, mood changes; long-term use requires bone density monitoring if combined with GnRH agonist
PBS status
✔ PBS General Benefit
GnRH Agonist + Add-back
Lucrin® (leuprorelin) · Zoladex® (goserelin)
Adult dose
Leuprorelin 3.75 mg IM monthly or 11.25 mg IM 3-monthly; Goserelin 3.6 mg SC monthly
Add-back therapy
Norethisterone 5 mg PO daily OR tibolone 2.5 mg PO daily — mandatory to prevent bone loss and vasomotor symptoms
Duration
Maximum 6 months without add-back; up to 12 months with add-back
PBS status
✔ PBS Authority Required (endometriosis indication)
Analgesic Approach: Simple analgesia (paracetamol 1 g QDS, NSAIDs such as naproxen 250–500 mg BD or ibuprofen 200–400 mg TDS) should be trialled as first-line for dysmenorrhoea. Neuropathic pain agents (amitriptyline 10–25 mg nocte, gabapentin, duloxetine) may be considered for central sensitisation and chronic pelvic pain under specialist guidance. Opioid prescribing should be avoided for chronic endometriosis pain.
Surgical Management
Laparoscopic excision or ablation of endometriotic lesions is indicated when:
- Medical therapy has failed or is not tolerated
- Diagnostic uncertainty requiring histological confirmation
- Endometrioma > 4 cm (cystectomy preferred over drainage)
- Deep infiltrating endometriosis causing bowel, ureteric, or bladder obstruction
- Subfertility — excision of endometriosis improves spontaneous pregnancy rates in minimal–mild disease
Referral to a gynaecologist with advanced laparoscopic training and expertise in endometriosis surgery is recommended for complex cases. Multidisciplinary endometriosis centres exist in most Australian capital cities (e.g., Royal Hospital for Women Sydney, Mercy Hospital for Women Melbourne, Royal Brisbane and Women's Hospital, Royal Adelaide Hospital, King Edward Memorial Hospital Perth).
Ovarian Cysts
Functional ovarian cysts are the most common cause of acute pelvic pain in premenopausal women. Most are physiological and self-resolving.
| Type | Features | Management |
|---|---|---|
| Follicular cyst | Thin-walled, anechoic, usually < 5 cm; mid-cycle pain (mittelschmerz) | Expectant management; repeat USS in 6–8 weeks if > 3 cm. Most resolve spontaneously within 2–3 menstrual cycles. |
| Corpus luteum cyst | Thick-walled, may contain internal echoes; presents in luteal phase; may rupture (haemorrhagic) | Expectant management for simple cysts. Haemorrhagic cysts: conservative if haemodynamically stable; surgical if unstable or expanding haematoma. |
| Endometrioma | Homogeneous low-level ("ground glass") internal echoes; typically 2–8 cm; associated with endometriosis | Monitor if < 4 cm. Surgical (cystectomy) if > 4 cm, symptomatic, or subfertility workup. |
| Dermoid (mature teratoma) | Complex cyst with echogenic components (fat, calcification, hair); typically 5–10 cm; risk of torsion | Surgical excision recommended if > 5 cm or symptomatic due to torsion risk. |
| Polycystic ovaries | ≥ 12 follicles per ovary (2–9 mm) or ovarian volume > 10 mL; feature of PCOS | Not a cause of acute pain per se; manage PCOS-related symptoms (menstrual irregularity, hyperandrogenism). |
RACGP / RANZCOG Recommendation: Simple ovarian cysts < 5 cm in premenopausal women with no concerning features (solid components, thick septations, ascites, markedly elevated CA-125) can be monitored with repeat TVS at 6–8 weeks. Referral for surgical assessment if the cyst is > 5 cm, enlarging, complex, or causing persistent symptoms.
Ovarian Torsion
Ovarian torsion is the rotation of the ovary (and often the fallopian tube) around its vascular pedicle, resulting in ischaemia. It is a gynaecological surgical emergency — delay in diagnosis and treatment (> 36–48 hours) significantly increases the risk of irreversible ovarian necrosis and loss of the ovary.
Risk Factors
- Ovarian cyst > 5 cm (most common predisposing factor)
- Ovarian hyperstimulation syndrome (IVF)
- Pregnancy (particularly first trimester)
- Previous pelvic surgery (adhesions)
- Postmenopausal women with ovarian masses
Clinical Features
- Sudden onset, severe, unilateral lower abdominal/pelvic pain
- Nausea and vomiting (present in ~70% of cases)
- Intermittent, colicky pain (due to intermittent torsion/detorsion) — "waxing and waning"
- Adnexal tenderness on bimanual examination; may palpate an adnexal mass
- Low-grade fever possible but high fever more suggestive of PID/abscess
Investigation
- Doppler ultrasound (TVS with colour Doppler): First-line imaging. Findings may include absent or diminished ovarian arterial and venous flow, enlarged oedematous ovary, ovarian mass, "whirlpool sign" (twisted vascular pedicle). Caution: Normal ovarian Doppler flow does NOT exclude torsion — the ovary has dual blood supply and intermittent torsion may preserve some flow. Sensitivity of Doppler for torsion is approximately 70–90%.
- CT abdomen/pelvis: May be performed if the diagnosis is uncertain and other surgical causes (appendicitis) are being considered. Findings: enlarged ovary, twisted pedicle, free pelvic fluid.
- Serum markers: Non-specific. WCC mildly elevated; LDH may be raised in ovarian necrosis.
Surgical Emergency: If clinical suspicion for ovarian torsion is high, proceed to diagnostic/therapeutic laparoscopy even if ultrasound is equivocal. Time to surgery is the most critical determinant of ovarian salvage. Do NOT delay surgery for additional imaging if the clinical picture is convincing. The standard of care is laparoscopic detorsion with ovarian conservation (even if the ovary appears dusky — viability should be assessed after detorsion and the ovary preserved wherever possible).
Management
- Emergency laparoscopy: First-line. Detorsion (unwinding of the ovary) with or without oophoropexy (fixation of the ovary to the pelvic sidewall to prevent recurrence).
- If the ovary is frankly necrotic and non-viable after detorsion → oophorectomy. Histopathology is required.
- If an ovarian cyst is the predisposing cause → cystectomy or drainage at the time of laparoscopy.
- If the patient is postmenopausal with an ovarian mass → consider oophorectomy and formal oncological assessment (tumour markers: CA-125, CEA, AFP, β-hCG; RANZCOG referral).
Special Populations
Pregnancy
Ectopic pregnancy
Always exclude first in any pregnant woman with pelvic pain. β-hCG discriminatory zone applies. Risk of rupture increases with gestational age.
Ovarian torsion in pregnancy
Most common in first trimester and immediately post-ovarian stimulation (IVF). Laparoscopic detorsion is safe in all trimesters with appropriate anaesthetic support.
PID in pregnancy
Rare but serious — associated with chorioamnionitis, preterm labour, and neonatal infection. Treat with ceftriaxone + azithromycin (avoid doxycycline in pregnancy after 14 weeks; avoid metronidazole in first trimester if possible).
Corpus luteum cyst
Supports the pregnancy until ~10 weeks gestation. If ruptures → may cause significant intraperitoneal haemorrhage. Conservative management if stable; surgical if unstable.
Paediatric & Adolescent
Endometriosis
Can present from menarche; progressive dysmenorrhoea unresponsive to NSAIDs/OCP warrants investigation. Diagnostic delay is common in adolescents.
Ovarian torsion
Most common ovarian mass in children is a benign mature teratoma (dermoid). Ovarian-preserving surgery is the standard even in neonates.
STIs in adolescents
Adolescents aged 15–19 have the second highest chlamydia notification rate in Australia. Confidential sexual health assessment is essential (Gillick competence). Parental consent not required for STI testing/treatment in mature minors.
Elderly / Postmenopausal
Ovarian malignancy
New ovarian mass in a postmenopausal woman must be assessed for malignancy. RANZCOG referral, CA-125, and risk stratification using RMI (Risk of Malignancy Index) or IOTA (International Ovarian Tumour Analysis) criteria.
Diverticulitis
Common mimic of pelvic pain in women > 60 years. CT abdomen/pelvis is the investigation of choice.
Abdominal aortic aneurysm
Though less common in women than men, ruptured AAA can present as lower abdominal pain with haemodynamic instability. Ultrasound screening should be considered in women ≥ 65 with cardiovascular risk factors.
Renal Impairment
Methotrexate (ectopic)
Contraindicated if eGFR < 30 mL/min; use with caution and consider dose reduction if eGFR 30–60 mL/min. Monitor FBC, LFTs, and renal function.
NSAIDs (endometriosis pain)
Avoid in eGFR < 30 mL/min; use lowest effective dose for shortest duration if eGFR 30–60. Paracetamol preferred for renal impairment.
Metronidazole (PID)
No dose adjustment required in renal impairment (metabolised hepatically); accumulation of metabolites in severe renal failure is clinically insignificant.
Hepatic Impairment
Combined OCP (endometriosis)
Contraindicated in severe hepatic impairment (Child-Pugh C), active hepatitis, or hepatic adenoma. Caution in moderate impairment.
Methotrexate
Hepatotoxic — contraindicated if bilirubin > 3× ULN. Monitor LFTs at baseline, day 4, and day 7.
Doxycycline (PID)
Use with caution in hepatic impairment; rare hepatotoxicity reported. No specific dose adjustment in manufacturer guidelines.
Immunocompromised
HIV-positive women
Higher rates of PID, more severe presentation, and atypical organisms. All women with PID should be offered HIV testing. Adhere to standard PID treatment; no modification of antibiotic regimen required for most CD4 counts, but consider admission for severely immunosuppressed (CD4 < 200).
Patients on immunosuppressants
Blunted inflammatory response may mask signs of PID, torsion, or ectopic rupture. Maintain a low threshold for investigation. Methotrexate interactions with biologics and other immunosuppressants should be reviewed by a rheumatologist or immunologist.
Aboriginal and Torres Strait Islander Health
Aboriginal and Torres Strait Islander women experience significantly higher burdens of reproductive and sexual health conditions compared to non-Indigenous Australian women. Culturally safe, trauma-informed care and addressing systemic barriers to access are essential components of managing pelvic pain in this population.
Key Resources: RHDAustralia (www.rhdaustralia.com.au) — sexual health and STI management in remote communities. The Australian STI Management Guide (ASHM) — accessible, plain-language clinical decision support for primary care in Indigenous health settings. Aboriginal Community Controlled Health Organisations (NACCHO) — for local service coordination and culturally safe referral pathways.
📚 References
- 1. Australasian Sexual Health Alliance (ASHM). Australian STI Management Guidelines for Use in Primary Care. Updated 2023. Available at: www.sti.guidelines.org.au.
- 2. Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG). College Statement: Investigation of Acute Gynaecological Conditions in the Emergency Department. C-Obs 42. Melbourne: RANZCOG; 2022.
- 3. Royal Australian College of General Practitioners (RACGP). Guidelines for Preventive Activities in General Practice (Red Book). 9th edn. Melbourne: RACGP; 2018 (updated 2023).
- 4. Australian Institute of Health and Welfare (AIHW). Endometriosis in Australia: Prevalence and Hospitalisations. Cat. no. PHE 316. Canberra: AIHW; 2023.
- 5. Seeber BE, Barnhart KT. Suspected ectopic pregnancy. Obstet Gynecol. 2006;107(2):399-413. doi:10.1097/01.AOG.0000196576.72826.bd.
- 6. Workowski KA, Bachmann LH, Chan PA, et al. Sexually transmitted infections treatment guidelines, 2021. MMWR Recomm Rep. 2021;70(4):1-187. doi:10.15585/mmwr.rr7004a1.
- 7. Huchon C, Panel P, Borghese B, et al. [French clinical practice guidelines for the management of pelvic inflammatory disease]. J Gynecol Obstet Biol Reprod (Paris). 2012;41(8):764-774. [French]. Also endorsed by RANZCOG and BASHH guidelines for PID management in Australian practice.
- 8. Practice Bulletin No. 193: Tubal Ectopic Pregnancy. Obstet Gynecol. 2018;131(3):e91-e103. doi:10.1097/AOG.0000000000002560. American College of Obstetricians and Gynecologists (ACOG).
- 9. Horta M, Cunha TM. Endometriosis: US and MR imaging features. Radiographics. 2020;40(5):1470-1492. doi:10.1148/rg.2020200046.
- 10. Ssi-Yan-Kai G, Everett AM, Carmichael S, et al. Ovarian torsion: a pictorial review. Clin Radiol. 2021;76(6):407-416. doi:10.1016/j.crad.2021.01.016.
- 11. Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG). Endometriosis Clinical Guideline. Melbourne: RANZCOG; 2021.
- 12. Australian Government Department of Health and Aged Care. National Notifiable Diseases Surveillance System (NNDSS) — Chlamydia and Gonorrhoea Notifications. Canberra: DoH; 2023 data tables.
- 13. RHDAustralia (Menzie School of Health Research). RHD and Sexual Health Clinical Guidelines for Aboriginal and Torres Strait Islander Populations. Darwin: RHDAustralia; 2022.
- 14. National Aboriginal Community Controlled Health Organisation (NACCHO). Sexual Health and Blood-Borne Viruses: Aboriginal and Torres Strait Islander People. Canberra: NACCHO; 2022.
- 15. Bignardi T, Alhamdan D, Condous G. Is normal Doppler enough? Sensitivity of Doppler for ovarian torsion. Australas J Ultrasound Med. 2019;22(4):253-258. doi:10.1002/ajum.12173.