Women's Health

Ectopic pregnancy

Ectopic pregnancy is implantation outside the uterine cavity, usually in a fallopian tube, a structure that cannot expand, so trophoblastic invasion ends in rupture and intraperitoneal haemorrhage.

In a nutshell

Ectopic pregnancy is implantation outside the uterine cavity, usually tubal; rupture causes intraperitoneal haemorrhage and remains a leading cause of early-pregnancy maternal death. Unstable or in significant pain means resuscitation and urgent surgery; otherwise pain, mass size, heartbeat, serum hCG and reliable follow-up choose between expectant management, methotrexate 50 mg/m2 intramuscularly and surgery.

Classic presentation

A woman in early pregnancy with one-sided pain, light bleeding and shoulder-tip pain, tachycardic, with a positive pregnancy test and an empty uterus on transvaginal scan.

Key points

About a third of women with an ectopic pregnancy have no known risk factor, so a clean risk history never excludes it.
Around 1 in 90 UK pregnancies is ectopic, roughly 11,000 a year, and about 95% of them are tubal.
Refer to early pregnancy assessment for bleeding with pain, 6 weeks or more, or uncertain dates. Under 6 weeks and pain free: repeat urine test in 7 to 10 days.
Atypical presentation is common: breast tenderness, gastrointestinal or urinary symptoms, passage of tissue, or rectal pressure and pain on defecation.
The BNF methotrexate monograph carries no ectopic pregnancy indication, so the ectopic dose comes from a local specialist protocol, not from the BNF.
Anti-D immunoglobulin is a protein obtained from blood plasma containing no blood cells, so the person must be able to make an informed choice.
Ectopic pregnancy is the most frequent cause of maternal death in early pregnancy in the UK and Ireland.
Recurrence risk after one ectopic pregnancy is around 10%, so arrange an early scan in the next pregnancy.

First-line investigation

Urine pregnancy test, then transvaginal ultrasound to locate the pregnancy; serial serum hCG 48 hours apart only when the location is unknown.

Management

Recognise rupture and resuscitate

Haemodynamic instability, or significant concern about pain or bleeding, goes directly to A&E. Tachycardia above 100 beats per minute or blood pressure below 100/60 mmHg is the threshold NICE names.¹
ABCDE, two large-bore cannulae, FBC and crossmatch, senior gynaecology and anaesthetics, then urgent surgery. Laparoscopy if the condition allows, laparotomy for severe haemorrhage.^1,7,6

Locate the pregnancy

Transvaginal ultrasound locates it. No intrauterine pregnancy seen means a pregnancy of unknown location: still potentially ectopic, whatever the hCG.^5,6
Two serum hCG as near as possible to 48 hours apart, no earlier. Do not use hCG to locate the pregnancy, or serum progesterone as an adjunct.^5,6
Rise above 63%: scan at 7 to 14 days, earlier if hCG is 1,500 IU/L or above. Fall above 50%: urine test 14 days after the second hCG.^5,6
A fall under 50% or a rise under 63%: clinical review in the early pregnancy assessment service within 24 hours. Give 24-hour safety-netting regardless of hCG.^5,6

Expectant management or methotrexate

Expectant: stable, pain free, ectopic under 35 mm, no heartbeat, hCG 1,000 IU/L or less, able to return. Consider up to below 1,500 IU/L.^7,6
Monitor expectant management with hCG on days 2, 4 and 7: a 15% or greater fall each time, then weekly until below 20 IU/L.^7,6
Methotrexate: no significant pain, unruptured, mass under 35 mm, no heartbeat, hCG below 1,500 IU/L, no intrauterine pregnancy, able to return.^7,6
Methotrexate 50 mg/m2 by deep intramuscular injection, single dose, typically 70 to 100 mg. NG126 states no dose and calls the use off label.^4,7,6
After methotrexate, hCG on days 4 and 7, then weekly until negative. A plateau or rise means reassessment for further treatment.^7,6
Avoid alcohol, NSAIDs, folic acid supplements, intercourse and sun. Use effective contraception and avoid conception for at least 3 months.^4,3,10

Surgery when indicated

Surgery first-line: cannot return for follow-up, significant pain, mass 35 mm or larger, visible fetal heartbeat, or hCG 5,000 IU/L or more.^7,6
hCG 1,500 to under 5,000 IU/L with all other criteria met: a choice of methotrexate or surgery, warning of the higher chance of further intervention.^7,6
Laparoscopic salpingectomy unless there are other infertility risk factors; salpingotomy if the other tube is damaged. Up to 1 in 5 salpingotomies need further treatment.^7,6

Anti-D, resolution and future pregnancy

No anti-D up to and including 11+6 weeks, including surgery. At 12+0 to 12+6 weeks give at least 250 IU (50 micrograms) intramuscularly if RhD-negative.^8,9
Ultrasound dating beats the last menstrual period, and 250 IU is a minimum: a larger stocked dose is acceptable.^8,9
Do not use a Kleihauer test to quantify feto-maternal haemorrhage.⁸
After salpingotomy hCG at 7 days then weekly; after salpingectomy a urine pregnancy test at 3 weeks. Offer self-referral to early pregnancy assessment next time.^7,6

Exam traps

A pregnancy of unknown location is not a diagnosis of miscarriage. Worsening symptoms need review whatever the hCG is doing.
An empty uterus with hCG above 1,500 IU/L is not automatically ectopic; NICE uses that level only to bring the scan forward.
Rupture has been reported with low, falling and even negative hCG, so a falling level is not a discharge criterion.
Do not use serum progesterone alongside serial hCG to tell an intrauterine from an ectopic pregnancy.
Never give methotrexate before a definitive ectopic diagnosis with a viable intrauterine pregnancy excluded.
The 15% day 4 to day 7 fall that triggers a second methotrexate dose is unit protocol, not NICE. NICE says only plateau or rise.
Expectant and medical management have the same resolution time and future fertility, so a low, falling hCG does not force methotrexate.
The anti-D rule is gestation-based, not procedure-based: surgical management before 12+0 weeks gets no anti-D, which reverses long-standing practice.

Illustrations

Tubal implantation and rupture mechanismDiagram showing trophoblastic invasion of the tubal wall, progressive distension of mesosalpinx vessels and the point of rupture causing intraperitoneal haemorrhage.PassFinals · original

Ectopic pregnancy at laparoscopyLaparoscopic view of a tubal ectopic pregnancy distending the fallopian tube.Mikael Häggström, Wikimedia Commons · CC-BY-SA-3.0

Anatomical sites of ectopic implantationDiagram of the fallopian tube and pelvis marking ampullary, isthmic, fimbrial, interstitial and non-tubal implantation sites.PassFinals · original

Key sources

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.