Ectopic Pregnancy

An ectopic pregnancy is a fertilised egg implanting and maturing outside the uterus. Ectopic pregnancies occur in about 1 in 80 pregnancies (1.25%).

97% of ectopic pregnancies are tubal. Non-tubal (interstitial, cervical, caesarean scar) are rare but higher-risk — see note at the end.

Red flags / presentation

• Acute abdomen, haemodynamic instability
• Pain + bleeding + amenorrhoea (or positive pregnancy test)
• β-hCG >5000 IU/L with no intrauterine pregnancy visible on TV scan is a higher-risk threshold requiring surgical management (see below) — the older “>1500 with no IUP” figure is the diagnostic discriminatory zone, not the surgical threshold.
• Pelvic/abdominal tenderness, cervical motion tenderness, adnexal mass, shoulder-tip pain, dizziness/syncope, tachycardia/hypotension.
• Previous ectopic pregnancy increases risk of recurrence.

Diagnostic ultrasound features

Reliable diagnosis on TV ultrasound if any of:

• Adnexal mass containing a gestational sac (± yolk sac/fetal pole/fetal heart) — very high specificity (~100%)
• Empty gestational sac within an adnexal mass (“bagel sign”), or an inhomogeneous adnexal mass (“blob sign”) — high specificity (~98%)

An empty uterus or fluid in the uterine cavity alone is not diagnostic (also seen in pregnancy of unknown location) — interpret alongside symptoms and serial β-hCG, and repeat the scan if the picture is unclear and the patient is stable.

Management of tubal ectopic pregnancy

Surgical management required (any of): haemodynamically unstable, signs of rupture, β-hCG >5000 IU/L, adnexal mass >35mm, or contraindication to medical/expectant management.

For stable women with an adnexal mass <35mm and no fetal heart activity, willing and able to attend follow-up:

β-hCG	Options
<1500 IU/L	Expectant OR methotrexate (MTX) OR surgical
1500–5000 IU/L, no significant pain/rupture signs	MTX OR surgical
>5000 IU/L	Surgical only

Methotrexate dosing (systemic):

• β-hCG <3000 IU/L or adnexal mass <20mm: one dose of systemic methotrexate
• β-hCG 3000–5000 IU/L or adnexal mass 20–35mm: two doses, 4–7 days apart

Two-dose regimens increase treatment success in these higher-hCG/larger-mass groups but also increase transient side effects (nausea, diarrhoea, mucositis, abdominal pain, mild lab abnormalities) — all self-limiting, none requiring hospitalisation. Follow-up β-hCG is required regardless of dosing, and further doses may be needed. Advise waiting 3 months before trying to conceive again after MTX, and discuss contraception.

Methotrexate is teratogenic — only give once an ectopic pregnancy is confirmed without doubt.

Discuss the options, with their benefits and risks, so the woman reaches an informed decision. Warn explicitly that emergency treatment may be required if expectant or medical management is unsuccessful — both need frequent monitoring and prompt access to surgery, which is a real access problem for rural and remote women.

Surgical choice: salpingectomy vs salpingotomy

Salpingectomy (tube removal) is preferred over salpingotomy (tube-preserving incision) — higher likelihood of complete resolution in a single procedure; salpingotomy carries a materially higher risk of treatment failure requiring further treatment (repeat surgery or MTX). Medical management (MTX) may favour a subsequent intrauterine pregnancy over surgery, but salpingectomy has the higher resolution rate of the ectopic itself.

Salpingotomy may still be reasonable for a woman who wants to avoid or can’t access IVF and values preserving the tube, provided she understands and accepts the higher failure risk — a shared decision, not a default.

On network meta-analysis, salpingectomy and multi-dose methotrexate both outranked expectant management for treatment success. Methotrexate may increase the chance of a later intrauterine pregnancy compared with surgery (OR 1.52, 95% CI 1.20–1.92, low certainty), but the evidence on recurrent ectopic pregnancy is too uncertain to guide choice.

Anti-D

• Surgically managed ectopic pregnancy: give anti-D immunoglobulin to Rh D-negative women.
• Medically or expectantly managed ectopic pregnancy: evidence is insufficient to say anti-D reduces sensitisation risk — consider it after discussion with the patient.
• Dose: 250 IU up to 12 weeks, 625 IU beyond 12 weeks (same as for miscarriage — see Miscarriage).

Non-tubal ectopic pregnancy (rare, higher-risk)

• Interstitial (proximal tubal segment within the myometrium): expectant management only if hCG <1500 IU/L, monitored to hCG <20 IU/L (decline can take 4–6 weeks); medical management with systemic or ultrasound-guided intra-sac MTX; surgical options are laparoscopic cornuostomy (preferred, better fertility/tube preservation) or cornual resection ± ipsilateral salpingectomy if high haemorrhage risk or medical/expectant management fails.
• Cervical: expectant management should be avoided (severe haemorrhage risk). Medical management (systemic or intra-sac MTX) for stable women. If unstable, MTX declined, or MTX fails: dilatation and curettage under ultrasound guidance (or operative hysteroscopy where available) ± adjuncts to control bleeding (Foley catheter tamponade, uterine artery embolisation/ligation).
• Caesarean scar pregnancy: high-risk (miscarriage, placenta accreta spectrum, uterine rupture, haemorrhage, hysterectomy). Type I (progresses toward the cervico- isthmic space/cavity) has better outcomes than Type II (progresses toward bladder/ abdominal cavity, more likely to rupture). Continuing a Type I pregnancy needs multidisciplinary tertiary care. For non-viable pregnancies: expectant management only if no embryonic activity; medical management with systemic or intra-sac MTX (2 doses 4–7 days apart if systemic); surgical options guided by type — D&C ± balloon tamponade or uterine artery embolisation for Type I, hysteroscopic/laparoscopic resection for Type II.