Gynecology Topic 38. Ectopic pregnancy

I. Ectopic Pregnancy

Definition

• Ectopic pregnancy: Implantation of the developing blastocyst outside the endometrium of the uterine cavity.
• Potentially life-threatening due to rupture → Intra-abdominal hemorrhage → Hemorrhagic shock.
• Usually presents in the 1st trimester, often 6-8 weeks after the last menstrual period.

Common Sites

1. Fallopian tube: ~95%.

• Ampulla: Most common tubal site.
• Isthmus.
• Fimbria.
• Interstitial / cornual part.

2. Ovary.
3. Abdomen.
4. Cervix.
5. Cesarean scar / uterine horn/interstitial region: Rare but important.

Etiology and Risk Factors

• Main mechanism: Tubal damage or impaired tubal transport → Delayed embryo passage → Ectopic implantation.
• Tubal damage:

• PID / Chlamydia / gonorrhea.
• Previous ectopic pregnancy.
• Tubal surgery, tubal ligation or sterilization failure.
• Previous pelvic/abdominal surgery → Adhesions/scarring.

• Assisted reproduction: IVF, ovulation induction.
• Contraceptive failure:

• IUD: Overall pregnancy risk is low, but if pregnancy occurs, ectopic risk is relatively higher.
• Progestin-only pills / estrogen-progestin contraception failure.

• Congenital anomalies of uterus/fallopian tubes.
• Smoking → Impaired tubal ciliary function.

II. Clinical Features

Typical Presentation

• Classic triad:

• Amenorrhea / delayed menses.
• Lower abdominal or pelvic pain, often unilateral.
• Vaginal bleeding, often dark brown spotting.

• Pelvic examination: Cervical motion tenderness, adnexal tenderness or adnexal mass.

Tubal Abortion

• Products of conception are expelled from the tube into the peritoneal cavity.
• Usually milder bleeding and pelvic pain than rupture.

Tubal Rupture

• Sudden severe pelvic/abdominal pain.
• Signs of peritonitis: Guarding, rebound tenderness, abdominal rigidity.
• Intra-abdominal bleeding:

• Shoulder-tip pain, syncope, dizziness.
• Pallor, tachycardia, hypotension.
• Hemorrhagic shock → Maternal death risk.

III. Diagnosis

Initial Principles

• Consider ectopic pregnancy in every reproductive-age patient with pelvic pain and/or vaginal bleeding until pregnancy is excluded.
• First step: Urine or serum beta-hCG.
• If beta-hCG positive → Assess hemodynamic stability immediately.

Beta-hCG

• Pregnancy test: Positive.
• Serial beta-hCG:

• Normal early intrauterine pregnancy usually rises predictably every 48 h.
• Ectopic pregnancy often rises more slowly or plateaus.
• Beta-hCG pattern alone cannot reliably exclude ectopic pregnancy.

• Discriminatory zone: If beta-hCG is above ~1500-2000 IU/L and no intrauterine gestational sac is seen on transvaginal US → Ectopic pregnancy must be strongly suspected.

Transvaginal Ultrasound

• First-line imaging in stable patients.
• Findings suggesting ectopic pregnancy:

• No intrauterine gestational sac despite beta-hCG above discriminatory zone.
• Adnexal mass / tubal ring.
• Extrauterine gestational sac with yolk sac or embryo ± fetal cardiac activity → Diagnostic.
• Free fluid in the pouch of Douglas or abdomen → Suspicious for rupture/bleeding.

Other Investigations

• CBC: Anemia/bleeding, leukocytosis if differential includes infection.
• Blood group/Rh status and crossmatch if bleeding or surgery likely.
• Baseline liver/renal function and blood count before methotrexate.
• Laparoscopy: Definitive diagnosis and treatment if imaging is inconclusive or surgery is indicated.

IV. Treatment

Emergency / Ruptured / Hemodynamically Unstable

• Immediate resuscitation:

• ABC, oxygen, 2 large-bore IV lines.
• IV crystalloid, blood products, crossmatch.

• Urgent surgery: Usually exploratory laparotomy if unstable; laparoscopy may be used if expertise and stability allow.
• Procedure:

• Salpingectomy: Removal of affected fallopian tube; typical if rupture, severe tubal damage, recurrent ectopic, large ectopic or no fertility desire.
• Salpingostomy: Opening the tube and removing ectopic tissue; fertility-preserving but needs beta-hCG follow-up due to persistent trophoblast risk.

Stable, Unruptured Ectopic Pregnancy

1. Medical treatment: Methotrexate.

• Folate antagonist → Stops trophoblastic proliferation.
• Candidate criteria:

• Hemodynamically stable.
• No rupture / no significant hemoperitoneum.
• Reliable follow-up and access to emergency care.
• Beta-hCG usually < 5000 IU/L.
• Mass usually < 3.5-4 cm.
• No fetal cardiac activity.

• Follow beta-hCG until undetectable; inadequate fall → additional methotrexate dose or surgery.

2. Surgical treatment: Laparoscopy.

• Salpingostomy: Fertility-preserving, useful if contralateral tube is damaged or fertility desired.
• Salpingectomy: Preferred if tube is ruptured/severely damaged, bleeding is significant, ectopic is recurrent in same tube or fertility is not desired.

Contraindications to Methotrexate

• Hemodynamic instability or suspected rupture.
• Inability to comply with follow-up.
• Breastfeeding.
• Significant liver disease, renal disease or blood dyscrasia.
• Immunodeficiency.
• Fetal cardiac activity, high beta-hCG or large ectopic mass → Relative/poor-prognosis factors.

V. Practical Points

• Positive pregnancy test + abdominal pain/bleeding + no confirmed intrauterine pregnancy = ectopic pregnancy until proven otherwise.
• Do not rely only on beta-hCG: Ectopic pregnancy can rupture even at relatively low levels.
• Free fluid + pain + positive beta-hCG → Treat as possible ruptured ectopic.
• After salpingostomy or methotrexate → Follow beta-hCG until negative.
• After one ectopic pregnancy → Future ectopic risk is increased; early TVUS is needed in the next pregnancy.