Makindo Medical Notes

An ectopic pregnancy must be suspected in any woman with a positive pregnancy test, amenorrhoea, abdominal or pelvic pain, or PV bleeding, as delayed or misdiagnosis can be fatal.

About

• Ectopic pregnancy is the most common cause of maternal death in the first trimester.
• Suspect ectopic pregnancy in any woman with a positive pregnancy test, amenorrhoea, pelvic pain, or PV bleeding.
• Classic signs include a positive β-HCG, an empty uterus, and an adnexal mass on ultrasound.
• Digital vaginal examination should be deferred until resuscitation facilities are available, as it may provoke rupture.
• In normal pregnancies, serum β-HCG doubles approximately every 48 hours.

Aetiology

• Ectopic pregnancy occurs when the embryo implants outside the uterine cavity, with 90% of cases in the fallopian tubes.
• Incidence is approximately 1 in 200 pregnancies and increases with maternal age.
• The ampullary region of the fallopian tube is the most common implantation site.

Physiology

• Fertilization normally occurs in the fallopian tubes, with the fertilized egg traveling down to implant in the uterine cavity.
• Factors like scarring or infection can prevent this process, resulting in implantation outside the uterus.

Risk Factors

• Previous ectopic pregnancy
• History of pelvic inflammatory disease (PID), intrauterine contraceptive device (IUCD) use, or endometriosis
• Previous abdominal or pelvic surgery
• Reversal of sterilization or in vitro fertilization (IVF) procedures
• Presence of ovarian or uterine cysts or tumors

Clinical Features (Pre-Rupture)

• Amenorrhoea, usually 5-8 weeks post-last menstrual period (LMP)
• Symptoms may mimic a normal early pregnancy (missed periods, breast tenderness, nausea).
• Unilateral lower abdominal pain
• Sharp, stabbing pelvic or abdominal pain
• Vaginal bleeding with a “prune juice” appearance in the first trimester
• Vasovagal episodes and potential haemorrhagic shock or syncope if ruptured
• Peritonitis or shoulder pain if ruptured, which constitutes a medical emergency.

Investigations

• Serum β-HCG: Monitors levels. In a normal pregnancy, levels double every 48 hours, while ectopic pregnancy may show a failure to rise.
• Ultrasound: Confirms extrauterine pregnancy or may show free fluid in the pouch of Douglas.
• Transvaginal Ultrasound: Shows an empty uterus, adnexal tubal sac, and free fluid in ectopic cases.
• Rhesus Status: Should be checked as anti-D immunoglobulin may be required.
• Laparoscopy: The definitive diagnostic procedure if non-invasive tests are inconclusive.

Differential Diagnosis

• Acute appendicitis
• Acute pelvic inflammatory disease (PID)

Management

• Medical Management (Early Ectopic Pregnancy):
  • Methotrexate and Misoprostol may be used if the sac is < 4 cm and β-HCG < 1500 IU/L.
  • Close monitoring of β-HCG is necessary, with follow-up visits to confirm resolution.
  • Methotrexate is a cytotoxic agent, with side effects such as nausea, vomiting, hair loss, and fatigue.
• Surgical Management:
  • Laparoscopic Salpingotomy: Often preferred in stable patients.
  • Immediate Intervention: For unstable patients, involving ABCs, resuscitation, blood cross-matching, and immediate surgical intervention (laparotomy and salpingectomy).
• Conservative Management: Suitable for asymptomatic patients with hCG < 1000 IU/L and a small adnexal mass (<2 cm). Regular monitoring of serum hCG to confirm a 15% reduction at each follow-up.
• Follow-up: Patients managed medically or conservatively should attend Early Pregnancy Assessment Unit (EPAU) visits until serum hCG levels return to negative.
• Rhesus Prophylaxis: Anti-D immunoglobulin (250 IU) should be offered to all Rh-negative women undergoing a surgical procedure for ectopic pregnancy.

References

• Royal College of Obstetricians and Gynaecologists Guideline