Ectopic Pregnancy on Contraception

Ectopic pregnancy is implantation outside the uterine cavity, most often in a fallopian tube. Most contraceptive methods reduce the absolute risk of ectopic pregnancy compared with using no method, but when a pregnancy occurs during use of a progestin-only method, an intrauterine device or after sterilisation, the proportion that is ectopic is higher. Any pregnancy with pain or bleeding in a contraceptive user is ectopic until proved otherwise.

Risk factors. Intrauterine device or sterilisation failure, progestin-only method failure, previous ectopic pregnancy, previous tubal surgery, pelvic inflammatory disease, chlamydia, smoking and assisted reproduction.

Presentation. Lower abdominal pain, vaginal bleeding, amenorrhoea, shoulder tip pain, dizziness, syncope, and in rupture, shock and peritonism.

Examination. Vital signs, abdominal tenderness, guarding and rebound, adnexal tenderness or mass on gentle bimanual examination.

Differential diagnosis. Miscarriage, threatened miscarriage, intrauterine pregnancy, ovarian cyst accident, appendicitis, pelvic inflammatory disease, urinary tract infection or stone and ovarian torsion.

Investigations.

• Urine and serum hCG.
• Transvaginal ultrasound. An intrauterine gestational sac with yolk sac excludes ectopic pregnancy in most cases. A pregnancy of unknown location needs serial hCG.
• Repeat serum hCG at 48 hours in a stable patient with a pregnancy of unknown location. A rise of less than 35 to 50% suggests abnormal pregnancy and a fall suggests miscarriage.
• Full blood count, blood group and rhesus status, cross match when unstable.
• Baseline creatinine and liver enzymes before methotrexate.

Where ultrasound is not available. Rely on clinical monitoring, repeat examination and early referral. Do not discharge a patient with pain and a positive test without a plan.

Unstable or ruptured. Resuscitate with two large cannulae, fluids and blood, then urgent laparotomy or laparoscopy. Salpingectomy is the usual operation.

Stable surgical management. Laparoscopic or open salpingectomy when the other tube is healthy. Salpingotomy when the other tube is damaged and future fertility is wanted.

Medical management (single dose methotrexate). Methotrexate 50 mg/m2 intramuscularly on day 1, hCG on days 4 and 7, and a second dose of 50 mg/m2 if the fall between days 4 and 7 is under 15%. Follow hCG weekly until undetectable. Suitable for a haemodynamically stable patient with hCG under about 5,000 IU/L, no foetal cardiac activity and an adnexal mass under 3.5 cm, who can return for follow up.

Contraindicated with a viable intrauterine pregnancy, renal or hepatic impairment, severe anaemia, leucopenia or thrombocytopenia, active peptic ulcer or breastfeeding. Stop folate supplements, avoid NSAIDs and avoid sunlight and sexual intercourse until hCG is undetectable.

Rhesus negative. Anti-D immunoglobulin 250 IU (50 micrograms) intramuscularly within 72 hours when not already sensitised.

Expectant management. Possible for a small asymptomatic ectopic with a falling low hCG and reliable follow up.

Contraceptive implications. After treatment, offer a method before discharge. After methotrexate, use effective contraception for at least 3 months.

Follow up. Weekly hCG to undetectable. Warn that pain may occur in the first days after methotrexate and that severe pain or faintness needs immediate review.

Method decisions. A previous ectopic pregnancy does not restrict the use of combined pills, progestin-only pills, injectables or implants. An intrauterine device is suitable after the pregnancy has resolved, and a copper device is the more reliable choice where there are no other concerns. Sterilisation is not advised for decisions made in distress.

Referral and escalation. Refer every suspected ectopic pregnancy for same day assessment where there is no ultrasound or theatre. Refer cervical, interstitial, caesarean scar, ovarian or abdominal ectopic pregnancy to a specialist unit.