Ectopic Pregnancy
Ectopic pregnancy is the implantation of a fertilised ovum outside the uterine cavity, most commonly in the fallopian tube. It is a potentially life-threatening condition due to the risk of tubal rupture and haemorrhage.
This updated UKMLA guide to ectopic pregnancy is based primarily on NICE NG126, which covers risk factors, symptoms, referral criteria, diagnosis and management.
Definition
Ectopic pregnancy refers to the implantation of a fertilised ovum outside the endometrial cavity of the uterus.
It accounts for ~2% of all pregnancies. [Ref]
Locations
Most common location of an ectopic pregnancy: ampulla of the fallopian tube [Ref]
- Other locations: isthmus > fimbrial > ovary > interstitium > abdomen
Location that carries the highest rupture risk: isthmus of the fallopian tube [Ref]
Causes and Risk Factors
The underlying cause of ectopic pregnancy is associated with factors that prevent normal transport of the fertilised ovum to the uterine cavity.
Key risk factors: [Ref1][Ref2]
- Previous ectopic pregnancy (8-15% risk of recurrence)
- PID
- Endometriosis
- Previous tubal surgery
- IUD in situ
- The absolute risk of pregnancy is rare in the presene of an IUD
- However, if it failed, the risk of ectopic implantation is increased
- Smoking
Importantly, ~50% of patients with ectopic pregnancy have no identifiable risk factors. [Ref]
Clinical Manifestation
Ectopic pregnancy typically presents in the 1st trimester, most commonly 5-6 weeks of gestation. [Ref]
The most important and feared complication is tubal rupture (→ haemorrhage → hypovolaemic shock → maternal death)
Unruptured Ectopic Pregnancy
Classic triad of ectopic pregnancy:
- Amenorrhea
- Vaginal bleeding
- Abdominal pain
Symptoms: [Ref]
- Missed period or +ve pregnancy test
- Vaginal bleeding / spotting (typically intermittent and light)
- Abdominal / pelvic pain
Signs: [Ref]
- Abdominal / pelvic / adnexal tenderness
- Cervical motion tenderness
Note that clinical features of ectopic pregnancy are non-specific and overlap significantly with early viable intrauterine pregnancy and miscarriage. [Ref]
Ruptured Ectopic Pregnancy
Symptoms: [Ref]
- Generalised, severe pain (from haemoperitoneum)
- Dizziness, syncope
- Shoulder tip pain (late sign – referred pain via the phrenic nerve from diaphragmatic irritation by intraperitoneal blood)
Signs: [Ref]
- Peritoneal signs (rigid abdomen, percussion tenderness, rebound tenderness)
- Signs of shock (e.g. tachycardia, hypotension, pallor)
Diagnosis
Referral Criteria
| Scenario | Referral recommendations | Rationale |
|---|---|---|
+ve Pregnancy test PLUS any of the following:
|
Immediate referral to early pregnancy assessment service (or out-of-hours gynaecology service) | Possible ectopic pregnancy |
Vaginal bleeding PLUS any of the following:
|
Refer to early pregnancy assessment service (or out-of-hours gynaecology service)
Urgency depends on clinical judgement |
Possible ectopic pregnancy or miscarriage |
Offer expectant management (instead of referring immediately) if ALL the following apply (low risk of ectopic pregnancy):
- <6 weeks of gestation
- PAINLESS bleeding
- No risk factors (e.g. previous ectopic pregnancy)
Expectant management involves:
- Safety netting – to return if bleeding continues or pain develops
- Repeat urine pregnancy test after 7-10 days, and return if +ve
Investigation and Diagnosis
Initial test: pregnancy test (serum β-hCG)
- Ectopic pregnancy would give a +ve pregnancy test
- However, this alone cannot diagnose ectopic pregnancy
Definitive test: TVUS
- Alternative: TAUS
- TAUS has a lower sensitivity and specificity compared to TVUS
- It can also be used to exclude differential diagnoses (e.g. acute appendicitis)
Stereotypical ultrasound findings in ectopic pregnancy:
- Empty uterus
- Presence of an adnexal mass (“tubal ring”)
Presence of free fluid in the peritoneal cavity (e.g. in the Pouch of Douglas) indicates haemoperitoneum, likely due to a ruptured ectopic pregnancy.
See section below for more details.
TVUS Findings and Interpretation
NICE has made the following extensive recommendations regarding TVUS findings in diagnosing ectopic pregnancy.
| Interpretation | TVUS findings |
|---|---|
| Diagnostic for ectopic pregnancy |
|
| High probability of ectopic pregnancy |
|
| Possible ectopic pregnancy |
|
Laboratory Findings
Serial hCG findings:
- A suboptimal increase in hCG over 48 hours would be suggestive of ectopic pregnancy (not diagnostic like imaging)
- NICE defines this as hCG increase <63% OR decrease <50% over 48 hours
- Normal pregnancy: hCG increases >63% over 48 hours
- However, serial hCG is primarily performed in the context of pregnancy of unknown origin
Anaemia may be seen in those with a ruptured ectopic pregnancy and subsequent haemorrhage.
Management
Ruptured Ectopic Pregnancy
Initial management: [Ref]
- A-E assessment
- Fluid resuscitation
- Crossmatch and blood transfusion as needed
Definitive management: immediate laparoscopic salpingectomy [Ref]
- Specific indications for emergency surgery are haemodynamic instability, symptoms of an ongoing ruptured ectopic mass, or signs of intraperitoneal bleeding
- Laparotomy is reserved for those with massive intra-abdominal haemorrhage, or when laparoscopic visualisation is compromised
Unruptured Ectopic Pregnancy
There are 3 main approaches to managing ectopic pregnancies:
- Expectant management
- Medical management
- Surgical management
Decision Algorithm
First, check for any indications to offer surgery as 1st line management – ANY of the following:
- Significant pain
- Adnexal mass ≥35 mm
- Visible fetal heartbeat on ultrasound
- hCG ≥5,000 IU/L
- Unable to return for follow-up (not explicitly stated by NICE)
If surgery is NOT indicated, choose between expectant and medical management:
| Approach | Indications (ALL must be met) |
|---|---|
| Expectant management |
|
| Medical management |
|
Advise that (based on limited evidence), there seems to be no difference in patient outcomes, following expectant and medical management.
Specifically, the rate of ectopic pregnancies ending naturally, risk of tubal rupture, need for additional treatment, health status, depression or anxiety scores.
Offer choice of medical OR surgical management if all the following are met:
- Serum hCG 1,500-5,000 IU/L
- Able to attend follow-up
- No significant pain
- Unruptured ectopic pregnancy
- Adnexal mass <35mm
- No visible heartbeat
- No intrauterine pregnancy (confirmed on ultrasound)
Details On Management Approaches
| Approach | Description |
|---|---|
| Expectant management |
|
| Medical management |
|
| Surgical management | Laparoscopic approach is preferred
Choice of surgery:
Rhesus-negative individuals who received surgical management of ectopic pregnancy should be offered anti-D immunoglobulin prophylaxis. |
References
Related Articles
Pregnancy of Unknown Location (PUL)