Ectopic Pregnancy

A 28 year old woman presents with 7 weeks of amenorrhea, lower abdominal pain, and vaginal spotting. She appears pale and anxious. Vital signs show tachycardia. Pregnancy test is positive. Pelvic examination reveals cervical motion tenderness and right adnexal tenderness. Transvaginal ultrasound shows no intrauterine pregnancy. Diagnosis?

Diagnosis is ectopic pregnancy.

1. Definition

Ectopic pregnancy is implantation of a fertilized ovum outside the uterine cavity. It is a potentially life-threatening condition due to risk of rupture and hemorrhage.

Approximately 97% occur in the fallopian tube, most commonly in the ampulla (~70%).

2. Sites

Tubal Sites (Most Common)

1. Ampulla (~70%)
2. Isthmus
3. Fimbria
4. Interstitial (tubal segment within myometrium)

Less Common Sites

1. Ovary
2. Cervix
3. Cesarean scar
4. Abdominal cavity

3. Risk Factors

1. Previous ectopic pregnancy
• Recurrence risk approximately 10% after one prior ectopic and >25% after multiple prior ectopics
2. Pelvic inflammatory disease (especially chlamydia or gonorrhea)
3. Tubal surgery or tubal damage
4. Infertility and assisted reproductive technology
5. Smoking
6. Endometriosis
7. Maternal age >35 years
8. Pregnancy occurring with an intrauterine device in place
9. Progesterone-only contraception
10. Congenital reproductive tract abnormalities

4. Pathophysiology

1. Impaired embryo transport through the fallopian tube
2. Tubal dysfunction caused by infection, surgery, smoking, inflammation, or hormonal factors
3. Implantation occurs outside the uterine cavity
4. Trophoblastic invasion causes local tissue destruction and vascular remodeling
5. Progressive growth may result in rupture and hemorrhage

5. Clinical Features

Classic Triad

1. Amenorrhea
2. Abdominal or pelvic pain
3. Vaginal bleeding

Additional Features

1. Unilateral pelvic pain
2. Adnexal tenderness
3. Cervical motion tenderness
4. Shoulder pain due to diaphragmatic irritation from hemoperitoneum
5. Dizziness or syncope
6. Rectal pressure
7. Hemodynamic instability if ruptured

6. Diagnosis

Diagnosis relies on:

1. Pregnancy testing
2. Quantitative serum β-hCG
3. Transvaginal ultrasound (TVUS)

6.1 Serum β-hCG

1. Serial β-hCG measurements are more informative than a single value
2. In viable intrauterine pregnancy with initial β-hCG <1500 mIU/mL, expected rise is typically ≥49% over 48 hours
3. Falling β-hCG suggests failing pregnancy
4. Plateauing or abnormally rising β-hCG increases suspicion for ectopic pregnancy

6.2 Transvaginal Ultrasound (Preferred Imaging)

Suggestive findings:

1. Empty uterine cavity despite positive pregnancy test
2. Adnexal mass
3. Extrauterine gestational sac
4. Yolk sac or embryo outside uterus confirms diagnosis
5. Free pelvic fluid suggests rupture

Discriminatory Zone

Absence of an intrauterine pregnancy when β-hCG is at or above the discriminatory level (commonly up to 3500 mIU/mL) raises concern for ectopic pregnancy but does not independently confirm the diagnosis and must be interpreted with clinical findings and serial testing

6.3 Pregnancy of Unknown Location (PUL)

Defined as:

1. Positive pregnancy test
2. No intrauterine pregnancy identified
3. No definite ectopic pregnancy identified

Management:

1. Serial β-hCG
2. Repeat transvaginal ultrasound
3. Clinical follow-up

6.4 Additional Evaluation

1. CBC
2. Blood type and Rh status
3. Baseline renal and liver function before methotrexate

7. Differential Diagnosis

1. Threatened miscarriage
2. Incomplete miscarriage
3. Ovarian torsion
4. Ruptured ovarian cyst
5. Hemorrhagic corpus luteum
6. Appendicitis
7. Pelvic inflammatory disease
8. Tubo-ovarian abscess

8. Management

Management depends on hemodynamic stability, β-hCG level, ultrasound findings, ectopic location, and fertility goals

8.1 Hemodynamically Unstable or Ruptured Ectopic Pregnancy

Immediate Surgical Management

1. Urgent laparoscopy or laparotomy
2. Salpingectomy commonly performed if severe tubal damage or rupture is present
3. Salpingostomy may be considered in selected patients for fertility preservation
4. Aggressive IV fluid and blood product resuscitation as needed

8.2 Expectant Management (Selected Cases)

May be considered if:

1. Hemodynamically stable
2. Minimal or no symptoms
3. Low and declining β-hCG
4. Reliable follow-up

Requires serial monitoring until β-hCG becomes undetectable

8.3 Medical Management (Methotrexate)

Candidates:

1. Hemodynamically stable
2. Unruptured ectopic pregnancy
3. Reliable follow-up
4. Desire fertility preservation

Treatment success decreases as initial β-hCG increases

Absolute contraindications:

1. Hemodynamic instability
2. Rupture
3. Significant renal or hepatic dysfunction
4. Immunodeficiency
5. Significant anemia, leukopenia, or thrombocytopenia
6. Breastfeeding
7. Active pulmonary disease or peptic ulcer disease
8. Inability to comply with follow-up

Relative contraindications:

1. Fetal cardiac activity
2. β-hCG >5000 mIU/mL
3. Adnexal mass >4 cm

Methotrexate Follow-up

1. Measure β-hCG on day 4 and day 7
2. ≥15% decline indicates treatment response
3. Continue weekly β-hCG monitoring until undetectable

Patient counseling:

1. Avoid folic acid supplementation
2. Avoid alcohol
3. Avoid NSAIDs
4. Avoid vigorous exercise and intercourse during treatment

8.4 Rh Immunoprophylaxis

Administer Rho(D) immune globulin to unsensitized Rh-negative patients according to gestational age and local protocol

9. Complications

1. Tubal rupture
2. Severe hemorrhage
3. Hemorrhagic shock
4. Blood transfusion
5. Infertility
6. Recurrent ectopic pregnancy
7. Psychological distress

10. Key Clinical Insight

Any woman of reproductive age presenting with abdominal pain or vaginal bleeding should be considered pregnant until proven otherwise and evaluated for ectopic pregnancy

11. Key Exam Points

1. Most commonly occurs in the ampulla of the fallopian tube
2. Classic triad = amenorrhea + abdominal pain + vaginal bleeding
3. TVUS is preferred imaging
4. Serial β-hCG trends are more informative than a single value
5. Empty uterus above discriminatory zone raises concern but does not confirm ectopic pregnancy
6. Shoulder pain suggests hemoperitoneum
7. Ruptured ectopic pregnancy requires immediate surgery
8. Methotrexate requires strict patient selection and follow-up
9. Pregnancy of unknown location requires serial reassessment
10. Early diagnosis improves fertility preservation and reduces maternal morbidity