Ectopic Pregnancy

Ectopic pregnancy is implantation of a fertilised ovum outside the uterine cavity, most often in the fallopian tube, due to impaired tubal transport after infection, surgery or smoking. It affects 1 to 2 percent of pregnancies and is a leading cause of first trimester maternal death through rupture and haemorrhage.

• Risk factors: previous ectopic, pelvic inflammatory disease, tubal surgery, intrauterine contraceptive device, assisted reproduction, smoking, endometriosis.
• About 95 percent are tubal.
• Early diagnosis allows conservative treatment.

Typical features are amenorrhoea of 6 to 8 weeks, lower abdominal pain and irregular vaginal bleeding. Examination may show adnexal tenderness, a mass, cervical excitation, and in rupture, shock and peritonism.

• Shoulder tip pain and syncope suggest intraperitoneal blood.
• Uterus smaller than dates.
• Differential diagnosis: threatened miscarriage, ruptured corpus luteum cyst, appendicitis, pelvic inflammatory disease, ovarian torsion, urinary tract infection.
• Complications: rupture, haemorrhagic shock, anaemia, tubal damage, infertility, recurrence, death.

The approach combines urine or serum hCG, transvaginal ultrasound and clinical assessment.

• Urine pregnancy test in every woman of reproductive age with pain or bleeding.
• Transvaginal ultrasound: empty uterus, adnexal mass, free fluid in the pouch of Douglas.
• Serum hCG: discriminatory level about 1500 IU/L, above which an intrauterine sac should be seen.
• Haemoglobin, blood group and Rhesus status, cross-match 4 units if unstable.
• Serial hCG and a repeat scan if no mass is seen.

The principle is stabilisation, then surgery for unstable patients and medical or surgical treatment for stable ones.

• Supportive: two large-bore cannulae, Ringer's lactate 1 litre rapidly, transfusion with blood for shock; avoid delaying surgery for resuscitation.
• Pharmacological: methotrexate 50 mg/m2 IM as a single dose on day 1 for stable women with hCG below 5000 IU/L, no fetal heart on scan, mass below 35 mm, normal liver and renal function; check hCG on days 4 and 7; if the fall is below 15 percent, repeat the dose; then weekly hCG until negative; avoid pregnancy for 3 months; avoid NSAIDs, alcohol and sun exposure during treatment; analgesia with paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours).
• Procedures: laparoscopic salpingectomy (preferred if the other tube is healthy); salpingotomy if the other tube is diseased and fertility is wanted; laparotomy if unstable.
• Special groups: Rhesus negative women give anti-D immunoglobulin 250 IU IM within 72 hours; breastfeeding or renal or hepatic impairment contraindicate methotrexate.
• Red flags: shoulder tip pain, collapse, pulse above 100 per minute, systolic below 90 mmHg, rising pain after methotrexate.
• Follow-up: weekly hCG to negative; early ultrasound in future pregnancies at 5 to 6 weeks; advise on recurrence risk of 10 to 15 percent; contraception for 3 months after methotrexate.