Based on the Department of Obstetrics and Gynaecology lecture (Dr Ritho), reorganised for the ward. Ectopic pregnancy is a life-threatening emergency in any woman of reproductive age with pain, bleeding or collapse: think of it first, exclude it last.
The reasoning chain: a woman of childbearing age with a missed period, bleeding and lower abdominal pain → is she stable or in shock → confirm pregnancy → find where it is (ultrasound plus hCG) → treat by stability and size: resuscitate and operate, or give methotrexate, or watch.
1. Definition and size of the problem
An ectopic pregnancy is one in which the fertilised ovum implants and develops outside the normal endometrial cavity. It occurs in about 1 in 80 spontaneously conceived pregnancies. It remains a leading cause of maternal death in the first trimester.
2. Where it implants
| Site | Share |
|---|---|
| Fallopian tube (ampulla commonest, then isthmus, fimbria, interstitial) | about 98% |
| Ovary | about 0.5% |
| Abdominal and intraligamentous | rare |
| Cervix | about 0.4% |
| Cornual / interstitial | rare but bleeds torrentially |
| Caesarean scar | increasing with caesarean rates |
3. Risk factors: ask about each one
Anything that damages the tube or slows the egg's passage:
- Previous pelvic inflammatory disease (chlamydia and gonorrhoea), the commonest cause
- Previous ectopic pregnancy
- Tubal surgery, tubal ligation (a pregnancy after sterilisation is ectopic until proved otherwise), tubal reconstructive surgery
- Contraceptive failure, especially an IUD (it prevents womb pregnancies better than tubal ones) and progestogen-only pills
- Infertility and assisted reproduction (IVF), especially with damaged tubes
- Previous induced abortion and tubal endometriosis
- Smoking
Roughly half of women with an ectopic pregnancy have no risk factor, so the absence of one never excludes it.
4. Natural history of a tubal pregnancy
The pregnancy ends in one of three ways: tubal rupture (heavy bleeding into the abdomen), tubal abortion into the peritoneal cavity (slower bleeding), or spontaneous resolution with reabsorption.
5. History: the classic triad
Missed period (amenorrhoea of 6 to 8 weeks) + vaginal bleeding + lower abdominal pain.
- The bleeding is usually scanty and dark, from the endometrium shedding because the pregnancy makes too little hormone to support it.
- The pain starts as a one-sided ache and may become sudden and severe on rupture. Shoulder-tip pain means blood under the diaphragm.
- Dizziness, fainting and collapse suggest rupture.
- Ask about every risk factor above and about contraception.
6. Examination
General: vital signs for hypovolaemia and blood loss. In a ruptured ectopic the patient may lie quietly, sweating and pale, with severe pallor out of proportion to the visible bleeding, a rapid feeble pulse, low blood pressure and cold clammy hands. Young women can keep their blood pressure until very late, so tachycardia is the early sign.
Abdomen: tense, tender lower abdomen, guarding and rebound if ruptured, shifting dullness from free blood, distended bowels. There is usually no mass.
Pelvic (done gently):
- Cervical motion tenderness ("chandelier sign") and extreme tenderness in the fornices (about 75%).
- A tender adnexal mass, a slightly enlarged globular uterus, a full pouch of Douglas and blanched vaginal mucosa.
- Do not repeat bimanual examinations: they can rupture a stable ectopic pregnancy.
7. Differential diagnosis
| Gynaecological | Non-gynaecological |
|---|---|
| Threatened, inevitable or incomplete miscarriage | Acute appendicitis |
| Ruptured corpus luteum cyst | Diverticulitis |
| Ovarian cyst accident (torsion, rupture) | Pyelonephritis, ureteric colic |
| Acute pelvic inflammatory disease | Perforated peptic ulcer |
| Red degeneration of a fibroid | Gastroenteritis |
8. Investigate with purpose
| Test | The question it answers |
|---|---|
| Urine pregnancy test (positive) | Is she pregnant? (Do this in every woman of reproductive age with abdominal pain.) |
| Serum β-hCG | Is the level rising normally? In a healthy early pregnancy it roughly doubles every 48 hours. A slow rise or plateau suggests ectopic or failing pregnancy |
| Transvaginal ultrasound | Is there a pregnancy in the uterus? No intrauterine pregnancy with a positive test, an adnexal mass (the "blob sign" or "bagel sign"), a "double ring" appearance, free fluid in the pouch of Douglas |
| Full blood count, group and crossmatch, clotting screen | How much blood has been lost, and is blood ready? |
| Rhesus group | Give anti-D immunoglobulin to rhesus-negative women |
The discriminatory zone: when the hCG is above about 1,500 to 2,000 IU/L, a normal uterine pregnancy should be visible on transvaginal ultrasound. If nothing is seen in the uterus at that level, ectopic pregnancy is likely. Below that level, repeat the hCG in 48 hours.
Where results can mislead: a negative urine test does not exclude a very early ectopic pregnancy (rare but possible); a "pseudosac" in the uterus can fool you into thinking the pregnancy is intrauterine; hCG can be lower than expected in an ectopic pregnancy and still rupture. When in doubt, keep the woman under review and do not discharge her without clear return advice.
9. Management
The woman is unstable or the ectopic has ruptured
This is an emergency:
- ABC. Call for senior help, two large-bore IV cannulae, crossmatch blood, and give IV fluids and blood. Give oxygen.
- Emergency surgery. In an unstable woman use laparotomy (the fastest way to reach and clamp the bleeding point). Do not delay surgery for further tests.
- Salpingectomy (remove the tube) is usually done in the emergency.
The woman is stable
Choose between expectant, medical or surgical care:
Expectant (watching): a small, falling hCG, no pain, and reliable follow-up.
Medical: methotrexate (a folate antagonist that stops the trophoblast dividing). Criteria:
- hCG below about 5,000 IU/L (some units use 3,000)
- No yolk sac or fetal heart on ultrasound, adnexal mass under 3.5 cm, no free fluid in the pouch of Douglas
- Haemodynamically stable, and able to attend follow-up (hCG on days 4 and 7, then weekly until negative)
- No contraindications: breastfeeding, immunodeficiency, peptic ulcer, active lung disease, kidney or liver impairment, a viable intrauterine pregnancy, methotrexate allergy
Advantages: avoids surgery and anaesthesia and preserves the tube and fertility. Side effects: abdominal pain in the first week (often "separation pain"; it can also be a rupture, so it needs review), nausea, stomatitis, conjunctivitis, dermatitis, hair loss, gastritis, pneumonitis, raised liver enzymes and bone marrow suppression. Advise her to avoid NSAIDs, folic acid supplements, alcohol, sun, and sexual intercourse during treatment, and to avoid pregnancy for 3 months.
Surgical: laparoscopy is the gold standard in a stable woman (less pain, shorter stay, faster recovery).
| Operation | When |
|---|---|
| Salpingectomy (remove the whole tube) | The default; the other tube is healthy; the tube is badly damaged or bleeding; the woman has completed her family |
| Salpingotomy / salpingostomy (open the tube, remove the pregnancy, leave the tube) | The other tube is damaged and she wants to conceive; needs follow-up hCG because trophoblast can persist |
| Partial salpingectomy | Rarely used |
10. Follow-up and counselling
- Anti-D to rhesus-negative women.
- Follow hCG to zero after any conservative treatment.
- Fertility: about two-thirds of women conceive again, but the risk of another ectopic pregnancy rises (about 10–15%). Advise an early scan in the next pregnancy (at 5 to 6 weeks).
- Treat chlamydia and trace partners. Counsel about contraception and the loss; offer psychological support.
Examiner questions
- A woman of 28 collapses with lower abdominal pain, a missed period and a positive urine test. What do you do in the first 10 minutes?
- State the criteria for treating an ectopic pregnancy with methotrexate.
- Why should a bimanual examination be avoided or done gently in a suspected ectopic pregnancy?
- What is the commonest site of an ectopic pregnancy, and what is the commonest risk factor?
Practice questions
1. The commonest site of ectopic pregnancy is: A. Ovary · B. Cervix · C. Fallopian tube (ampulla) · D. Abdominal cavity · E. Caesarean scar Answer: C. About 98% are tubal.
2. A woman has a missed period, a positive pregnancy test, pelvic pain and no intrauterine pregnancy on ultrasound with hCG 4,000 IU/L. She is stable. Which treatment suits her best if she meets the other criteria? A. Observation only · B. Methotrexate · C. Misoprostol · D. Laparotomy · E. Reassurance Answer: B.
3. A woman with an ectopic pregnancy is rhesus negative. She needs: A. Nothing · B. Iron · C. Anti-D immunoglobulin · D. Folic acid · E. Antibiotics Answer: C.
4. Which finding is the most reliable sign of a ruptured ectopic pregnancy? A. Scanty dark vaginal bleeding · B. Shock with a tense tender lower abdomen and free fluid · C. Positive pregnancy test · D. Breast tenderness · E. Nausea Answer: B.
5. Which woman is at the HIGHEST risk of an ectopic pregnancy? A. A woman on combined pills · B. A woman with a previous ectopic pregnancy and a history of pelvic inflammatory disease · C. A woman who has had three vaginal deliveries · D. A woman using condoms · E. A nulliparous woman Answer: B.