USMLE Step 2 CK Lecture Notes 2019: Obstetrics/Gynecology (Kaplan Test Prep)

OB TRIAD

Ectopic Pregnancy

Ectopic pregnancy (1% of pregnancies; 15% if patient has had one ectopic
pregnancy) is pregnancy in which implantation has occurred outside of the
uterine cavity. The most common location is an oviduct; within the oviduct, the
most common location is the distal ampulla.

With a positive pregnancy test, the differential diagnosis consists of a
threatened abortion, incomplete abortion, ectopic pregnancy, and hydatidiform
mole. In a reproductive-age woman with abnormal vaginal bleeding, always
consider the possibility of pregnancy or complication of pregnancy.

The most common predisposing cause is previous pelvic inflammatory disease
(PID). Ectopic pregnancy risk is increased from any obstruction of normal
zygote migration to the uterine cavity from tubal scarring or adhesions from any
origin: infectious (PID, IUD), postsurgical (tubal ligation, tubal surgery), or
congenital (diethylstilbestrol [DES] exposure).

Scarring    or  Adhesions   Obstructing Normal  Zygote  Migration

Infectious Pelvic   inflammatory    disease

Postsurgical Tuboplasty/ligation

Congenital Diethylstilbestrol

Secondary   amenorrhea

Unilateral  abdominal/pelvic    pain

Vaginal bleeding