• Approximately 1–2% of all pregnancies are ectopic ^[1][2].
• In populations using assisted reproductive technology (ART), the rate can be higher (~2–5%).
• The incidence has risen over recent decades due to increasing rates of PID (especially Chlamydia trachomatis), ART use, and improved diagnostic sensitivity (detecting ectopic pregnancies that might previously have resolved spontaneously as "tubal abortions").

• Ectopic pregnancy remains the leading cause of pregnancy-related death in the first trimester in developed countries.
• In Hong Kong, maternal mortality from ectopic pregnancy is low due to rapid access to emergency services, but delayed presentations (particularly in recent immigrants and socially deprived women) still occur ^[3].

• Peak incidence in women aged 25–34 years.
• "Several of the women who died were socially deprived, and included recent immigrants, women with language barrier, and those with itinerant occupations or previous substance abuse. Such factors may make assessment or communication difficult or lead to a delay in seeking help." ^[3]
• Rising rates of Chlamydia trachomatis infection in Hong Kong contribute to tubal damage.

The fallopian tube (oviduct; "salpinx" in Greek — hence "salpingectomy") is ~10–12 cm long and has four anatomical regions, from lateral to medial:

After ovulation, the oocyte is picked up by the fimbriae and propelled toward the uterus by:

1. Ciliary beat of the tubal epithelium (toward the uterus)
2. Tubal peristalsis (smooth muscle contractions)
3. Tubal fluid flow

Anything that damages cilia (infection, smoking), impairs smooth muscle function (progesterone, nicotine), or physically obstructs the lumen (adhesions, endometriosis) → delayed ovum transport → the embryo reaches implantation stage while still in the tube → tubal ectopic pregnancy.

The fallopian tube lacks:

• Submucosal (stromal) layer seen in the endometrium — no decidual reaction to limit trophoblastic invasion
• Distensible capacity — the thin muscular wall of the ampulla or the narrow isthmus cannot accommodate a growing gestational sac
• Adequate blood supply for a placenta — trophoblast invasion erodes into tubal vessels, eventually causing rupture and haemorrhage

The result: the pregnancy either:

• Tubal abortion — expels through the fimbrial end (relatively benign)
• Tubal rupture — trophoblast erodes through the tubal wall → massive haemoperitoneum → hypovolemic shock

The sites of ectopic pregnancy and their relative frequencies ^[1][2]:

"Most common site of tubal ectopic pregnancy is Ampullary ~80%" ^[1]

Step 1: Impaired Ovum Transport

• Any of the risk factors above (tubal damage, smoking, hormonal changes) delays the passage of the fertilised ovum through the fallopian tube.

Step 2: Ectopic Implantation

• By day 6–7 post-fertilisation, the blastocyst is ready to implant. If still in the tube, it implants into the tubal mucosa.
• Trophoblastic cells invade the tubal wall (just as they would invade the endometrium), but the tube lacks a decidual reaction to limit invasion.

Step 3: Growth and Vascular Erosion

• The trophoblast erodes into tubal blood vessels to establish a blood supply.
• The gestational sac grows, distending the tube.
• hCG is produced → detectable in serum/urine (this is why pregnancy tests are positive).
• The corpus luteum in the ovary is maintained by hCG → continues progesterone production → the endometrium undergoes decidual change (Arias-Stella reaction) even though the pregnancy is not intrauterine.

Step 4: Clinical Consequences

• Tubal stretching → abdominal/pelvic pain (localised to the side of the ectopic)
• Decidual shedding from the endometrium (because the ectopic pregnancy produces hCG erratically, failing to maintain a stable endometrium) → vaginal bleeding (typically dark, scanty, "prune juice" like — NOT the bright red brisk bleeding of a miscarriage)
• Tubal rupture → sudden, severe abdominal pain + intraperitoneal haemorrhage → haemoperitoneum → hypovolemic shock
• Tubal abortion → the pregnancy is expelled through the fimbrial end → blood collects in the Pouch of Douglas → pelvic pain, sometimes shoulder tip pain

Step 5: Haemoperitoneum (if ruptured)

• Free blood in the peritoneal cavity irritates the peritoneum → peritonism (guarding, rebound tenderness)
• Blood tracking under the diaphragm irritates the phrenic nerve (C3, C4, C5) → referred shoulder tip pain (a classic and important symptom)
• If bleeding is massive → hypovolemic shock (tachycardia, hypotension, pallor, altered consciousness) ^[4][5]

In a normal intrauterine pregnancy (IUP):

• β-hCG roughly doubles every 48 hours in early pregnancy (the "doubling time")
• This reflects healthy, rapidly proliferating trophoblast

In an ectopic pregnancy:

• The trophoblast is implanted in a suboptimal environment → growth is slower and erratic
• β-hCG rises at a subnormal rate (< 66% rise in 48 hours) or may plateau or fall
• A "discriminatory level" of β-hCG (typically 1,500–2,000 IU/L for TVUS) is used: at this level, an IUP should be visible on transvaginal ultrasound. If the uterus is "empty" at this β-hCG level → suspect ectopic pregnancy ^[6]

When an ectopic pregnancy fails or is interrupted, progesterone support for the endometrium is lost → the entire decidualised endometrium can be shed as a decidual cast — a triangular piece of tissue that may be mistaken for products of conception (POC) from a miscarriage. This is a trap: if the tissue is sent for histology and shows only decidua WITHOUT chorionic villi, this supports the diagnosis of ectopic pregnancy.

As above (tubal [ampullary, isthmic, fimbrial, interstitial], ovarian, cervical, caesarean scar, abdominal, intramural, heterotopic).

• Expectant management (observation with serial β-hCG)
• Medical management (methotrexate)
• Surgical management (laparoscopy or laparotomy; salpingectomy or salpingotomy)

(Detailed management will be covered in a subsequent section as per your instructions)

This is an important interim diagnostic category:

• Positive pregnancy test BUT no pregnancy visualised on ultrasound (neither intrauterine nor ectopic)
• Could represent: very early IUP, ectopic pregnancy, or complete miscarriage
• Managed with serial β-hCG monitoring and repeat ultrasound

Ectopic pregnancy presents with the classic triad of: ^[1][2]

1. Missed period (amenorrhoea)
2. Vaginal bleeding
3. Abdominal pain

However, "clinical diagnosis can only be made in half of the patients" ^[1] — the presentation is frequently atypical. Maintain a high index of suspicion.

"It is important to recognize that the clinical presentation is often not 'classical'. β-hCG testing should be considered in any young woman with unexplained abdominal pain whether she has missed a period or had abnormal vaginal bleeding." ^[3]

• Haemoperitoneum (along with splenic rupture, ruptured AAA, ruptured HCC, ruptured ovarian cyst) ^[4]
• Hypovolemic shock (haemorrhagic causes include ruptured ectopic) ^[5]
• Acute abdomen in women of reproductive age

• PID (especially Chlamydia trachomatis) ^[7]
• ART/IVF
• Tubal surgery
• Endometriosis

Why the confusion arises: Both present with amenorrhoea + PV bleeding + positive pregnancy test. A woman having a complete miscarriage has an "empty uterus" on ultrasound — this can be mistaken for a resolved pregnancy when it may actually be an ectopic. "An ultrasonically 'empty' uterus in a woman who presents with vaginal bleeding in pregnancy may indicate an ectopic pregnancy." ^[3]

The decidual cast passed in ectopic pregnancy may be mistaken for products of conception from a miscarriage. If tissue is obtained, send for histology — the absence of chorionic villi confirms it was NOT an intrauterine pregnancy.

Subtypes of miscarriage to consider:

• Threatened: PV bleeding, closed os, viable IUP on scan — may settle
• Inevitable: Open os, heavy bleeding, IUP still present but non-viable
• Incomplete: Some products retained, open os
• Complete: All products passed, empty uterus — TRAP: looks like ectopic on scan
• Missed (silent): No symptoms, non-viable IUP found incidentally on scan

• Why it's in the differential: Presents with PV bleeding + positive pregnancy test + amenorrhoea — just like ectopic.
• Distinguishing features:
  • β-hCG is markedly elevated (often > 100,000 IU/L) — in ectopic, it is usually low and plateauing
  • Uterus may be larger than dates
  • USS shows "snowstorm" appearance (complete mole) or mixed echogenic pattern (partial mole)
  • May have hyperemesis gravidarum, hyperthyroidism (hCG cross-reacts with TSH receptor), theca lutein cysts
  • "Gestational trophoblastic disease is an important differential diagnosis of threatened miscarriage" ^[2]

• Definition: Simultaneous intrauterine pregnancy AND ectopic pregnancy.
• Incidence: ~1 in 30,000 with natural conception, but up to 1 in 100 with ART — so it is increasingly common.
• Why it's dangerous: The presence of a confirmed IUP on ultrasound gives false reassurance, and the coexisting ectopic is missed.
• Key teaching: In ART patients, confirming an IUP does NOT exclude ectopic pregnancy. Always examine the adnexa.

• After ovulation, the corpus luteum forms and is maintained by hCG in early pregnancy.
• It can become cystic, and may rupture → intraperitoneal bleeding → mimics ruptured ectopic.
• Distinguishing feature: An intrauterine pregnancy is confirmed on ultrasound. The bleeding is from the ruptured corpus luteum, NOT from an ectopic site. β-hCG trend is normal.
• If there is no IUP visible and the adnexal finding could represent either a corpus luteum cyst or an ectopic, this is a pregnancy of unknown location (PUL) and requires serial β-hCG.

Ovarian cyst complications: sudden onset lower abdominal pain ^[8]

Mechanism of confusion: Both ovarian cyst rupture and ruptured ectopic cause sudden lower abdominal pain, free fluid on USS, and possibly haemodynamic instability. The pregnancy test is the critical differentiator.

"PID: lower abdominal pain (lower than appendicitis), usually bilateral and exacerbated by coitus (dyspareunia)" ^[8]

Why the overlap: PID and ectopic pregnancy share cervical excitation and adnexal tenderness — both involve pelvic peritoneal irritation. Furthermore, PID is a risk factor for ectopic pregnancy, so the two can be linked in the same patient's history. Note that PID can rarely co-exist with early pregnancy.

"Mittelschmerz: mid-cycle lower abdominal/pelvic pain due to rupture of follicular cyst and bleeding → irritate peritoneum" ^[8]

• Occurs at mid-cycle (day 14 of a 28-day cycle) — correlates with ovulation.
• Pain is usually mild, self-limiting, unilateral.
• Pregnancy test negative.
• Important because it represents a physiological cause of lower abdominal pain + mild free fluid on USS.

• Chronic cyclical pelvic pain (dysmenorrhoea, dyspareunia, dyschezia).
• Endometrioma ("chocolate cyst") can rupture → sudden severe pain + peritoneal irritation.
• Pregnancy test negative.
• USS: "ground glass" echogenicity of endometrioma contents.

• Usually in older reproductive-age women.
• Red degeneration (particularly in pregnancy) causes acute pain ± fever.
• USS: well-defined uterine mass with heterogeneous echotexture.
• Pregnancy test may be positive if concurrent pregnancy (red degeneration is more common in pregnancy).

This is one of the most important surgical mimics, especially for a right-sided ectopic pregnancy.

"Ectopic pregnancy" is listed as a key differential of appendicitis in female patients ^[8][9].

Why it matters: The negative appendectomy rate historically has been up to 15–30%, especially in women of reproductive age where gynaecological mimics are common ^[8]. This is why a serum pregnancy test and pelvic USS are essential in any woman of childbearing age with RIF pain before proceeding to appendicectomy.

"Should ALWAYS take a full gynaecological history, especially menstrual cycle, vaginal discharge and possible pregnancy" ^[8] in any woman with RIF pain.

"Ureteric colic: colicky pain typically waxes and wanes, each episode lasting 20–60 min" ^[8]

• Severe, gripping, true colicky pain — radiates from loin to groin following the course of the ureter.
• Key difference from ectopic: The pain in ureteric colic is colicky (comes and goes with pain-free intervals as the ureter spasms around the stone), whereas ectopic pain tends to be more constant. Ectopic does not typically radiate to the groin.
• Microscopic or gross haematuria on urinalysis.
• Pregnancy test negative.
• CT KUB (non-contrast) is the gold standard for diagnosis.

"Right pyelonephritis: preceded by irritative urinary symptoms (frequency, urgency), associated with loin tenderness, high fever ( > 39°C), rigors, pyuria" ^[8]

• Suprapubic pain (cystitis) or loin pain (pyelonephritis).
• Dysuria, frequency, urgency — these urinary symptoms are NOT typical of ectopic pregnancy.
• Pyuria and bacteriuria on urinalysis.
• Pregnancy test negative.

• Diffuse abdominal cramps, watery diarrhoea, vomiting.
• Why it's a dangerous mimic: "Gastrointestinal symptoms may be prominent in ectopic pregnancy, notably diarrhoea and painful defecation" ^[3] — blood in the Pouch of Douglas irritates the rectum and causes diarrhoea and tenesmus, mimicking gastroenteritis. A woman with a ruptured ectopic may be misdiagnosed as having food poisoning.
• Key difference: Gastroenteritis usually causes diffuse crampy pain with prominent vomiting/diarrhoea and no PV bleeding. Temperature may be elevated. No adnexal tenderness. Pregnancy test negative.

Life-threatening medical DDx of acute abdomen: MI, DKA, Addisonian crisis ^[4][9]

• DKA: Abdominal pain can be severe and mimic a surgical abdomen. Check blood glucose and ketones. Usually has a history of diabetes.
• Acute MI: Referred epigastric/abdominal pain (especially inferior MI). ECG and troponin.
• These are less likely to be confused with ectopic pregnancy specifically, but are included in the "acute abdomen" differential for completeness.

• Any woman of reproductive age with abdominal pain, PV bleeding, or collapse → urine pregnancy test.
• "A negative pregnancy test effectively rules out ectopic pregnancy" ^[1]
• If positive → proceed.

• Is the patient stable or unstable?
• Unstable = tachycardia, hypotension, peritonism, signs of shock → assume ruptured ectopic → "Women in haemorrhagic shock following rupture of ectopic pregnancy need to be transferred promptly to the operating theatre (OT)... Transfer must not be delayed by attempts to try to re-establish a normal circulating plasma volume" ^[3]
• "For unstable patients — if obviously a ruptured ectopic, focus on resuscitation and prepare the OT" ^[2]
• Stable → proceed to USS.

The USS findings fall into three categories (NICE NG126 2019): ^[1]

1. Diagnostic of ectopic: Adnexal mass with sliding sign, containing yolk sac or fetal pole → confirmed ectopic → proceed to management
2. High probability of ectopic: Bagel sign / tubal ring, or complex inhomogeneous adnexal mass separate from ovary → treat as ectopic
3. Uncertain / PUL: Empty uterus, no adnexal mass → need serial β-hCG

Also assess:

• "Empty uterus or pseudo-sac" ^[1] — do NOT mistake pseudo-sac for IUP
• "Moderate to large amount of free fluid in POD suggestive of haemoperitoneum" ^[1] — even in a "stable" patient, this is worrying and may tip toward surgical management

• Correlate the β-hCG level with USS findings:
  • β-hCG > discriminatory level (1,500–2,000 IU/L) + empty uterus → high suspicion for ectopic (or complete miscarriage)
  • β-hCG < discriminatory level + empty uterus → too early to see on USS → PUL → serial monitoring

"Should repeat test no less than 48 hours after the first test → assess trend" ^[2]

• Normal rise ( > 66%) → likely early IUP → repeat USS when β-hCG reaches discriminatory level
• Subnormal rise ( < 66%) or plateau → likely ectopic or failing IUP → clinical decision needed (repeat USS, consider intervention)
• Fall > 50% → likely complete miscarriage → continue serial β-hCG to confirm resolution

Important nuance: A subnormal rise does NOT definitively distinguish ectopic from failing IUP. Both can show this pattern. The clinical decision at this point involves:

• Repeat USS (an ectopic may now be visible at a higher β-hCG)
• Consider endometrial curettage (to look for villi — if present, it's a failing IUP; if absent, ectopic is more likely)
• Consider diagnostic laparoscopy if clinical suspicion is high

Suitable for expectant management ^[1][2]:

• β-hCG < 1,500 IU/L
• Ectopic pregnancy < 35 mm with no visible heartbeat on TVS
• Clinically stable and pain-free
• Able to return for follow-up

Why these criteria?

• β-hCG < 1,500: Low trophoblastic burden → high likelihood of spontaneous resolution. Higher levels indicate more viable, actively growing trophoblast that is less likely to resolve on its own.
• < 35 mm, no heartbeat: Small size and absence of cardiac activity indicate a non-viable or minimally viable ectopic → more likely to self-resolve. A heartbeat means a live ectopic that will continue to grow.
• Stable and pain-free: No evidence of impending rupture.
• Able to return: Essential because the patient must be monitored closely — if hCG rises or symptoms develop, management must escalate.

If unsuitable for expectant management → offer medical treatment or surgery ^[1]

Unsuitable if:

• β-hCG ≥ 1,500 IU/L
• Ectopic ≥ 35 mm or heartbeat visible
• Significant pain
• Unable to return for follow-up
• Patient preference for active treatment

• Serial β-hCG every 48 hours initially, then weekly
• Expectation: β-hCG should progressively decline
• Monitor for resolution: β-hCG falls to < 5 IU/L (essentially undetectable → confirms complete resolution)
• Safety netting: Provide clear instructions to return immediately if pain worsens, PV bleeding increases, or symptoms of shock develop
• Success rate: ~50–70% of carefully selected cases resolve spontaneously

Methotrexate (MTX) — let's break down the name and mechanism:

• "Metho-" = methyl group; "trex-ate" = relates to folic acid (pteroylglutamic acid)
• It is a folic acid antagonist (anti-metabolite)
• Mechanism: Inhibits dihydrofolate reductase (DHFR) → blocks the conversion of dihydrofolate to tetrahydrofolate → impairs thymidylate and purine synthesis → blocks DNA synthesis → kills rapidly dividing cells
• The trophoblast is one of the most rapidly dividing cell populations in the body → methotrexate selectively destroys it → the ectopic pregnancy involutes

Why MTX works for ectopic pregnancy: The ectopic trophoblast is metabolically active, rapidly dividing tissue. By depriving it of folate needed for DNA synthesis, MTX causes trophoblast necrosis → hCG production stops → the ectopic pregnancy resorbs.

"Medical therapy should be offered to suitable women" ^[1]

Suitable for medical treatment (methotrexate) ^[1][2]:

• No significant pain
• An unruptured ectopic pregnancy with an adnexal mass smaller than 35 mm with no visible heartbeat visible on ultrasound scan
• No intrauterine pregnancy (as confirmed on ultrasound scan)
• Able to return for follow-up
• β-hCG between 1,500–5,000 IU/L ^[2] (some guidelines accept up to 5,000 IU/L)

Pre-treatment blood tests must confirm ^[1]:

• Normal ALT (< 2× upper limit of normal)
• Normal Creatinine
• WBC > 3 × 10⁹/L
• Platelets > 100 × 10⁹/L
• Serum β-hCG < 5,000 IU/L

Unsuitable for medical treatment ^[1][2]:

"Methotrexate IM 50 mg/m²" ^[1] — single-dose protocol

Single-dose protocol (most common):

• Methotrexate 50 mg/m² body surface area given as a single intramuscular (IM) injection
• Body surface area (BSA) calculated from height and weight (Du Bois formula)

Multi-dose protocol (for higher β-hCG or larger ectopics):

• Methotrexate 1 mg/kg IM on Days 1, 3, 5, 7 alternating with folinic acid (leucovorin) 0.1 mg/kg on Days 2, 4, 6, 8
• Folinic acid "rescues" normal cells from MTX toxicity (it bypasses the DHFR block)
• Used less commonly; reserved for higher-risk cases

If β-hCG does not fall ≥ 15% between Day 4 and Day 7:

• Consider a second dose of methotrexate
• If still not declining → surgical management

Success rate: ~85–90% with single-dose protocol when patients are properly selected (β-hCG < 5,000, no heartbeat, < 35 mm)

• Avoid alcohol (hepatotoxicity risk)
• Avoid folic acid supplements (counteracts MTX effect)
• Avoid NSAIDs (reduce renal clearance of MTX → increased toxicity)
• Avoid sexual intercourse until β-hCG is undetectable (risk of tubal rupture)
• Reliable contraception for 3 months after MTX (teratogenic — must not conceive)
• Return immediately if severe pain, dizziness, or fainting (signs of rupture)
• Avoid sun exposure (photosensitivity)

Surgical management is indicated when ^[1][2]:

• Ectopic pregnancy > 35 mm, or with heartbeat
• Significant abdominal pain
• Unable to return for follow-up
• Medical treatment refused by woman
• β-hCG > 5,000 IU/L
• Failed expectant or medical management (rising β-hCG despite MTX)
• Haemodynamically unstable / ruptured ectopic (emergency indication)

"Laparoscopic approach is preferable to an open approach" ^[1]

"The decision to treat ectopic pregnancy by laparoscopic rather than open surgery should be based on the experience and expertise of the operator and a judgement about the suitability of the procedure for the individual woman" ^[3]

"Non-sensitised Rh negative women should receive anti-D immunoglobulin" ^[1]

• Why? During an ectopic pregnancy (and especially during rupture, surgery, or MTX-induced trophoblast destruction), fetal red blood cells carrying Rh-D antigen can enter the maternal circulation. If the mother is Rh-negative, she may develop anti-D antibodies → risk of haemolytic disease of the fetus and newborn (HDFN) in subsequent Rh-positive pregnancies.
• Dose: 250 IU anti-D IM if < 12 weeks; 500 IU if ≥ 12 weeks (with Kleihauer test to detect large feto-maternal haemorrhage)
• Timing: Within 72 hours of the sensitising event

• Cannot use methotrexate (would kill the IUP)
• Management: Surgical removal of the ectopic component (salpingectomy) while preserving the IUP
• Local injection of KCl into the ectopic sac under USS guidance is an alternative

• Ectopic pregnancy is the loss of a pregnancy — patients (and partners) need emotional support
• Provide information about support groups (e.g., The Ectopic Pregnancy Trust)
• Discuss future fertility prospects (generally good — ~65% subsequent IUP rate, ~10% recurrence rate)
• Counsel about need for early USS in future pregnancies to confirm IUP

This is the most feared and life-threatening complication — the reason ectopic pregnancy is classified as a gynaecological emergency.

Pathophysiology (from first principles):

• The fallopian tube has a thin muscular wall (especially the ampulla) and no submucosal decidual layer to limit trophoblastic invasion.
• As the ectopic pregnancy grows, trophoblast erodes through the tubal wall into the tubal blood vessels.
• Eventually, the tube cannot contain the expanding gestational sac → tubal rupture.
• Ruptured tubal vessels bleed directly into the peritoneal cavity → haemoperitoneum.
• The uterine and ovarian arteries (which anastomose in the mesosalpinx) supply the tube, so arterial bleeding can be brisk and massive.

"Tubal pregnancy ± rupture into abdominal cavity" ^[5]

Timing of rupture depends on the site ^[1]:

• Ampullary (~80% of tubal ectopics): Thinnest wall → ruptures at 8–12 weeks, or may undergo tubal abortion before rupture
• Isthmic (~12%): Narrow, thick-walled → ruptures earlier (6–8 weeks) because the lumen is small and the growing sac is quickly constrained
• Interstitial (1–6%): Surrounded by myometrium → can expand until 12–16 weeks → catastrophic haemorrhage when it ruptures due to rich blood supply from the uterine-ovarian arterial anastomosis
• Fimbrial (~5%): More likely to undergo tubal abortion (see below) than frank rupture

Clinical consequence:

• "Sudden onset severe lower abdominal pain on side of ectopic pregnancy → becomes generalized and associated with signs/symptoms of shock (fainting, collapse) if ruptured" ^[5]
• "Shoulder tip pain if blood collects beneath the diaphragm" ^[5] — "bleeding stimulating phrenic nerve" ^[2]
• Haemoperitoneum can be massive (1–3 litres or more) → class III–IV haemorrhagic shock

The end-stage of uncontrolled haemoperitoneum.

Ruptured ectopic pregnancy is listed as a cause of haemorrhagic hypovolemic shock ^[12].

Pathophysiology:

• Massive intraperitoneal blood loss → reduced circulating blood volume → reduced venous return → reduced cardiac output → inadequate tissue perfusion → end-organ damage
• Compensatory mechanisms: baroreceptor-mediated sympathetic activation → tachycardia, vasoconstriction (cold extremities, pallor), sweating, oliguria

Clinical features of hypovolemic shock: mainly characterized by increased sympathetic outflow ^[12]:

• "Vasoconstriction leading to pallor, peripheral cyanosis, cold extremities, delayed capillary refill"
• "Empty peripheral veins"
• "Tachycardia"
• "Sweating"

Classes of haemorrhagic shock (ATLS classification):

A ruptured ectopic can progress from Class I to Class IV within minutes, especially interstitial ectopics.

Consequence if untreated: Multi-organ failure (acute kidney injury from renal hypoperfusion, myocardial ischaemia, cerebral hypoxia) → maternal death.

• Definition: The ectopic pregnancy is expelled through the fimbrial end of the tube into the peritoneal cavity.
• Pathophysiology: Peristaltic contractions of the tube push the detaching gestational sac distally through the open fimbrial end. Blood and tissue enter the peritoneal cavity.
• Clinical consequence: Less catastrophic than frank rupture, but still causes:
  • Haemoperitoneum (variable volume; usually less than rupture)
  • Blood collecting in the Pouch of Douglas → pelvic pain, rectal symptoms ("diarrhoea and painful defecation" ^[3])
  • Can resolve spontaneously or may require intervention if ongoing bleeding
• More common with fimbrial and ampullary ectopics.

• Definition: A longstanding ectopic pregnancy that has neither fully ruptured nor fully resolved — it persists as an organised pelvic mass.
• Pathophysiology: Repeated small episodes of tubal bleeding → haematoma formation → organisation with fibrin and inflammatory tissue → dense pelvic adhesions → encapsulated mass ("pelvic haematocele")
• Clinical features: Chronic pelvic pain, low-grade β-hCG, pelvic mass on examination, may mimic ovarian neoplasm or endometrioma
• Diagnosis: Often challenging; may require laparoscopy
• Significance: The adhesions can further compromise tubal function and fertility

• When: Massive haemorrhage from ruptured ectopic → consumption of clotting factors and platelets
• Pathophysiology: Tissue factor release from damaged tubal tissue + massive blood loss → activation of the coagulation cascade → widespread microvascular thrombosis → consumption of fibrinogen, platelets, and clotting factors → paradoxical uncontrollable bleeding
• Clinical features: Oozing from IV sites, mucosal bleeding, widespread bruising, failure of blood to clot
• Laboratory: Low fibrinogen, elevated D-dimer, prolonged PT/aPTT, thrombocytopaenia, schistocytes on blood film
• Management: Treat the underlying cause (surgical haemostasis), replace clotting factors (FFP, cryoprecipitate), platelets, packed RBCs. Massive transfusion protocol (1:1:1 ratio of packed cells : FFP : platelets)

• Ectopic pregnancy remains the leading cause of pregnancy-related death in the first trimester in developed countries.
• Death results from uncontrolled haemorrhage → irreversible hypovolemic shock.
• "Several of the women who died were socially deprived, and included recent immigrants, women with language barrier, and those with itinerant occupations or previous substance abuse" ^[3] — social factors contribute to delayed presentation and delayed diagnosis.
• Mortality is highest with interstitial ectopic (richest blood supply), delayed diagnosis, and delayed surgical intervention.

This is one of the most significant long-term consequences for the patient.

Why fertility is reduced:

1. Loss of the affected tube (after salpingectomy) → only one tube remains for natural conception. If the remaining tube is healthy, the IUP rate is still ~60–70% over the subsequent years, but this is lower than the general population.
2. Tubal damage (the underlying pathology that caused the ectopic — PID, endometriosis — is usually bilateral) → the contralateral tube may also be compromised even if it appears grossly normal.
3. Adhesion formation from surgery or haemoperitoneum → impairs ovum pickup by the fimbriae.
4. "Grossly normal and patent are different concepts" ^[2] — a tube that looks normal on the outside may have internal mucosal damage that impairs function.

Fertility outcomes after ectopic pregnancy:

• Subsequent IUP rate: ~60–70% (with one healthy tube)
• Recurrence of ectopic: ~10% after one ectopic; ~25% after two ectopics
• If both tubes are damaged/removed → IVF is the route to pregnancy (bypasses the tubes entirely)

• The single strongest risk factor for ectopic pregnancy is a previous ectopic ^[1].
• Why? The same underlying tubal pathology (PID damage, smoking effects, congenital abnormalities) that caused the first ectopic is usually bilateral or persistent → the contralateral tube is at risk.
• After salpingotomy (tube-conserving surgery), the repaired tube itself has a higher recurrence rate (~15–20%) because the damaged mucosa and scarring provide a nidus for re-implantation.

Risk factors for recurrence ^[1]:

• Previous ectopic pregnancy
• Tubal damage from infection/surgery
• Ongoing smoking
• History of infertility

Clinical implication: All women with a history of ectopic pregnancy should have an early TVUS (at ~6 weeks) in any subsequent pregnancy to confirm intrauterine location. They should also be counselled to present early if they develop any symptoms (pain, bleeding) in future pregnancies.

• Who is at risk: Rh-negative women who were not given anti-D immunoglobulin at the time of ectopic pregnancy.
• Mechanism: Fetal red blood cells (which may be Rh-positive) enter the maternal circulation during ectopic pregnancy, rupture, surgery, or MTX-induced trophoblast destruction → maternal immune system produces anti-D IgG antibodies → in a subsequent Rh-positive pregnancy, these antibodies cross the placenta and cause haemolytic disease of the fetus and newborn (HDFN).
• Prevention: "Non-sensitised Rh negative women should receive anti-D immunoglobulin" ^[1] — within 72 hours of the sensitising event.

"Outline of emotional impact on the couple with early pregnancy losses" ^[1][2]

This is often underestimated but is a very real and important complication.

Why ectopic pregnancy causes psychological distress:

1. Pregnancy loss: The woman has lost a wanted (or sometimes unwanted but still emotionally significant) pregnancy. The grief response is similar to miscarriage or stillbirth.
2. Emergency nature: Many women experience the terror of haemorrhagic shock, emergency surgery, and fear of death — this can cause post-traumatic stress disorder (PTSD).
3. Loss of reproductive capacity: Salpingectomy means permanent loss of one tube; concerns about future fertility.
4. Recurrence anxiety: Knowing the recurrence rate is ~10% → anxiety in every subsequent pregnancy ("Will it happen again?")
5. Relationship strain: Partners may also experience grief and anxiety; the couple may struggle with intimacy (fear of pregnancy) and communication.
6. Social isolation: Others may not recognise ectopic pregnancy as a "real" pregnancy loss → inadequate social support.

Psychological conditions reported after ectopic pregnancy:

• Grief and bereavement
• Anxiety (especially about future pregnancies)
• Depression
• PTSD (especially after emergency presentation/surgery)
• Relationship difficulties

Management:

• Acknowledge the loss — validate the patient's grief
• Provide clear information about what happened and what to expect
• Counselling referral if needed
• Support groups (e.g., The Ectopic Pregnancy Trust)
• Follow-up appointment to discuss future fertility, contraception, and psychological wellbeing
• Screen for depression/PTSD at follow-up visits
• Reassure (with honesty) about future fertility prospects (~60–70% subsequent IUP rate)