Ectopic Pregnancy: Pathogenesis and Clinical Findings
In vitro fertilization
Tubal disorders leading to infertility and unknown procedural causes
Previous ectopic pregnancy
Underlying tubal disorder leading to previous ectopic
Pelvic inflammatory disease (PID)
Endometriosis
Tubal surgery or disorders
Age >35
Risk factor accumulation over time
Smoking
Impairment in tubal motility; impaired immunity (risk factor for PID)
Tubal scarring leading to adhesions, obstruction, and alteration of tubal function
Ectopic Pregnancy:
Implantation of developing blastocyst outside the uterine cavity, most commonly in fallopian tube (other locations: interstitial > cornual > cervical > ovarian > abdominal)
Embryo releases human chorionic gonadotropin (β-hCG), which supports corpus luteum to continue producing progesterone
On transvaginal ultrasound: Extrauterine gestational sac with a yolk sac or embryo
Embryo & trophoblast deathàloss of hormone support for the decidua (modified endometrial lining)
Progesterone maintains the endometrial lining, preventing it from shedding
Missed period
Penetration of ovum into muscular wall of fallopian tube
Tubal distention àTubal rupture
Intra-abdominal hemorrhage
Pregnancy cannot survive without the uterine endometrium
Maternal blood extrudes through fimbriae of fallopian tubes and into peritoneal cavity
Lower abdominal pain (including peritonitis in cases of hemoperitoneum)
Hemoperitoneum
(blood in the peritoneal cavity)
Sloughing of decidua out of the uterus through the vagina
Vaginal bleeding (usually in first trimester)
Cessation of human chorionic gonadotropin (β-hCG) release from embryo
β-hCG plateaus or decreases
Authors: Jemimah Raffé-Devine Tahsin Khan Yan Yu* Reviewers: Brianna Ghali Bishwas Paudel Mackenzie Grisdale Christina Schweitzer Ron Cusano* Jadine Paw* * MD at time of publication
Syncope
↓ Level of consciousness
Positive β-hCG, but rising <35% over 2 days Discriminatory zone: β-hCG >2000 + absence of intrauterine pregnancy
Hypotension
Shock
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Published Oct 1, 2017, updated Oct 19, 2021 on www.thecalgaryguide.com