Ectopic pregnancy

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Ectopic pregnancy



Ectopic pregnancy


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USMLE® Step 1 questions

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Ectopic pregnancy

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USMLE® Step 1 style questions USMLE

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A 25-year-old woman comes to the office due to vaginal bleeding and abdominal pain for the past 2 days. The patient’s last menstrual cycle was 6 weeks ago. She is sexually active with her male partner of 2 years, and they have been using the withdrawal method as contraception. Medical history is unremarkable other than an episode of pelvic pain 2 years ago that resolved spontaneously without treatment. Temperature is 37.0°C (98.6°F), pulse is 80/min, and blood pressure is 135/85 mmHg. Serum hCG is positive, measuring 1200 mIU/mL. Transvaginal ultrasound shows an empty, normal-appearing uterus and no other abnormalities. Physical examination shows mild lower right adnexal tenderness but is otherwise unremarkable. Which of the following is the underlying cause of this patient’s presentation?

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Abdominal pain

ectopic pregnancy p. NaN


ectopic pregnancy and p. NaN

Ectopic pregnancy p. NaN

appendicitis differential diagnosis p. 392

Chlamydia trachomatis p. , 147

hCG in p. 658

Kartagener syndrome p. 47

methotrexate for p. 448

salpingitis and p. 182


ectopic pregnancy p. NaN


ectopic pregnancy p. NaN

Pelvic inflammatory disease (PID) p. 182

ectopic pregnancy p. 666


ectopic pregnancy and p. NaN


In ectopic pregnancy, ectopic means “out of place,” so an ectopic pregnancy means that a pregnancy occurs somewhere other than in the uterine cavity.

In order for an ectopic pregnancy to take place, a couple of things need to happen differently from the normal process of a pregnancy.

First, following ovulation, the egg must be fertilized and come to rest somewhere other than the endometrium of the uterine cavity.

Next, when it arrives at this destination, it must implant on a surface with a rich enough blood supply to support a developing embryo.

Ectopic pregnancies have been known to occur on various surfaces, including the ovaries, intestines, and most commonly, in the ampulla of the Fallopian tube.

After implantation, the embryo begins developing and growing just like it would in a normal pregnancy.

Over time, a few different things can happen. Sometimes the tissue can no longer provide a sufficient blood supply for the embryo, leading to its death.

On the other hand, if the tissue can supply the embryo with sufficient blood, then hormones from the corpus luteum and placenta can lead to a missed menstrual period and other body changes like nausea and fullness of breasts, which are typically seen in early pregnancy.

If the ectopic pregnancy occurs in the ampulla of the fallopian tube, it eventually runs out of space.

Slowly the ectopic pregnancy stretches the nerve fibers within the wall of the fallopian tube, causing lower abdominal pain.

Eventually, the expansion causes damage to the wall of the ampulla, potentially rupturing the fallopian tube.

A ruptured ectopic can also lead to massive hemorrhaging into the abdominal cavity, and the blood can irritate the peritoneum which can cause referred pain to the shoulder.


  1. "Robbins Basic Pathology" Elsevier (2017)
  2. "Harrison's Principles of Internal Medicine, Twentieth Edition (Vol.1 & Vol.2)" McGraw-Hill Education / Medical (2018)
  3. "Pathophysiology of Disease: An Introduction to Clinical Medicine 8E" McGraw-Hill Education / Medical (2018)
  4. "CURRENT Medical Diagnosis and Treatment 2020" McGraw-Hill Education / Medical (2019)
  5. "Does This Woman Have an Ectopic Pregnancy?" JAMA (2013)
  6. "Diagnosing ectopic pregnancy and current concepts in the management of pregnancy of unknown location" Human Reproduction Update (2013)
  7. "Ectopic pregnancy" The Lancet (2005)

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