SUPERStudy: Ectopic pregnancy

Introduction: An ectopic pregnancy occurs when a fertilized ovum implants and grows outside the endometrium lining the uterine cavity, most commonly in the fallopian tube. It is the leading cause of pregnancy-related death in the first trimester. 

Incidence:  approximately 2% of pregnancies

Common Sites of Ectopic Pregnancy:

1.Fallopian tube (95-98%): Ampullary segment (most common); isthmus; fimbrial end; interstitial portion

2. Other less common sites: Ovary; abdominal cavity; cervix; cesarean section scar
3. Heterotopic pregnancy refers to the rare occurrence of an intrauterine pregnancy with a synchronous ectopic pregnancy.

Risk Factors:

1.Previous ectopic pregnancy:  It has the highest odds ratio for recurrence. 

2.Pelvic inflammatory disease (PID): Causes tubal damage.

3.History of sexually transmitted infections: increases the risk 

4.Tubal surgery/ligation: Including sterilization or tubal reconstruction.

5.Intrauterine device (IUD): Though rare, pregnancy with IUD in place increases the risk of ectopic. If a patient becomes pregnant while using an intrauterine device for birth control there is up to a 50% risk that it will be an ectopic pregnancy.

6.Assisted reproductive technologies (ART): Such as IVF.

7.Cigarette smoking: Impairs tubal motility.

8.Endometriosis: Causes pelvic adhesions

9.Maternal age 35 – 44: Age-related change in tubal function

10.Prior pharmacologically induced abortion

Clinical Features:

1.The most common presenting complaint is vaginal bleeding. Classic Triad (Occurs in ~50% of cases): Amenorrhea; vaginal bleeding (spotting or light bleeding) and abdominal pain (often unilateral)

2.Other Symptoms: Shoulder tip pain (referred pain from diaphragmatic irritation due to hemoperitoneum); syncope or dizziness (due to blood loss); palpable adnexal mass (on pelvic examination)

3.Severe Presentation (ruptured ectopic): Signs of hypovolemic shock: Hypotension, tachycardia, pallor, acute, severe abdominal pain.

Diagnosis:

1.History and Physical Examination: Detailed menstrual history; assess for risk factors and clinical signs.

2.Laboratory Tests: β-hCG levels: The most specific and sensitive test. In a normal intrauterine first-trimester pregnancy, the hCG level should double about every 48 hours. Serial β-hCG measurements show a slower-than-expected rise in ectopic pregnancy. Many practitioners regard a rise of less than 35% over 48 hours as very good evidence of a nonviable pregnancy.

CBC: May show anemia if bleeding is significant.

3.Imaging: Transvaginal ultrasound (TVUS): Absence of intrauterine pregnancy with an adnexal mass or free fluid in the pelvis is highly suggestive. The “identification of a gestational sac” is misleading because an ectopic pregnancy can be associated with an irregularly shaped fluid collection in the midline of the uterine cavity, a so-called pseudogestational sac. A normal gestational sac would be eccentrically located and have a decidual sign, which is an echogenic rim around the gestational sac that is absent in a pseudogestational sac. When the quantitative hCG exceeds 3500 mIU/mL and the transvaginal sonogram does not show an intrauterine gestational sac, then the risk of ectopic pregnancy is very high.Fluid in Morison’s pouch on transabdominal scanning strongly suggests ruptured ectopic pregnancy, usually requiring operative intervention. 

Other ancillary US findings suggestive of ectopic pregnancy in high-risk patients: complex pelvic mass, tubal ring, hepatorenal free fluid. 

4.Diagnostic Laparoscopy: Considered gold standard if the diagnosis remains uncertain.

Management:

1.Expectant Management: For select stable patients with declining β-hCG and no evidence of rupture.

2.Medical Management: Methotrexate, a folic acid antagonist, is the principal form of medical therapy. It inhibits trophoblastic cell division. It is highly successful, leading to resolution of properly chosen ectopic pregnancies in 85% to 90% of cases. With the multidose regimen, leucovorin is added to blunt MTX toxicity. Leucovorin is folinic acid and has folic acid activity. Thus, it allows some purine and pyrimidine synthesis to buffer side effects.

Indications: Hemodynamically stable, unruptured ectopic, small ectopic mass ≤ 3.5 cm,  and β-hCG <5000 IU/L. Requires follow-up of β-hCG levels to confirm resolution.

3.Surgical Management: Laparoscopic salpingectomy or salpingostomy: Indicated in hemodynamically unstable patients, ruptured ectopic, or if methotrexate is contraindicated. 

Salpingectomy (removal of the affected tube) is usually performed for those gestations too large for conservative therapy, when rupture has occurred, or for those women who do not want future fertility.

Salpingostomy: For a woman who wants to preserve her fertility and has an unruptured tubal pregnancy, less often, a salpingostomy can be performed. 

Complications:

1.Acute Complications: Tubal rupture leading to massive hemorrhage and hypovolemic shock.

2.Chronic Complications: Future infertility due to tubal damage. Increased risk of recurrent ectopic pregnancy.

SUPER Takeaways:

1.Early recognition is critical: Be vigilant in any woman of reproductive age presenting with abdominal pain and/or vaginal bleeding.

2.TVUS and β-hCG are diagnostic cornerstones: The combination is essential for early diagnosis.

3.Prompt intervention saves lives: Ensure proper triage to medical or surgical management based on patient stability.

4.Educate patients about prevention: Encourage STI prevention and prompt treatment to reduce risks. Understanding ectopic pregnancy helps prevent delays in diagnosis and ensures effective management, minimizing morbidity and mortality.

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