Ectopic Pregnancy (Unruptured)

Ectopic pregnancy is the implantation of a fertilized ovum outside the uterine cavity, occurring in 1–2% of pregnancies and accounting for 2.7% of pregnancy-related deaths and 6% of maternal deaths in early pregnancy. [1-2] Over 90% are tubal in location. [3] Approximately 40% are misdiagnosed at the initial visit, making a high index of suspicion essential. [4]

• Classic triad: Amenorrhea, vaginal bleeding, and lower abdominal/pelvic pain — though fewer than half present with all three [2]
• Pain characterization: Unilateral or bilateral, crampy, dull, or sharp; ranges from mild to debilitating; may be localized to the iliac fossa or diffuse [2]
• Vaginal bleeding: Typically intermittent, light, bright or dark red, rarely exceeds normal menstrual flow [5]
• Timing: Symptoms typically present at 5–8 weeks gestational age; ask about LMP, cycle regularity, and possibility of pregnancy
• Important negatives: Passage of tissue (does not distinguish miscarriage from ectopic — may represent decidual cast); shoulder pain (late sign suggesting hemoperitoneum) [2]
• Ask about contraceptive use, IUD in situ, fertility treatments, and desire for pregnancy

• Hemodynamic instability: Hypotension, tachycardia, diaphoresis, syncope → suspect rupture [2][5]
• Peritoneal signs: Rebound tenderness, guarding, rigid abdomen
• Shoulder tip pain: Diaphragmatic irritation from hemoperitoneum — a late and ominous sign [2]
• Severe, sudden-onset, generalized abdominal pain (may paradoxically improve briefly after rupture) [2]
• β-hCG >3,500 mIU/mL with no intrauterine pregnancy on TVUS and no history of recent miscarriage → highly suspicious for ectopic [6]
• Free fluid in the pelvis on ultrasound without an IUP → suspect ruptured ectopic with hemoperitoneum [6-7]

• Methotrexate (MTX): Standard medical management for unruptured ectopic; 50 mg/m² IM (single-dose protocol most common) [6][8]
• Contraindications to MTX (absolute): Hemodynamic instability, hepatic/renal dysfunction, immunodeficiency, active pulmonary disease, breastfeeding, peptic ulcer disease, blood dyscrasias [9]
• Must discontinue: Folic acid supplements and prenatal vitamins (reduce MTX efficacy) [9]
• Avoid during MTX treatment: NSAIDs (increase MTX toxicity via reduced renal clearance), alcohol, folic acid–containing foods in excess
• Rh immunoglobulin: Administer to Rh-negative patients

• Avoid folic acid–fortified foods and supplements during MTX treatment, as they antagonize the drug's mechanism [8-9]
• Avoid alcohol during and after MTX treatment (hepatotoxicity risk)
• Maintain adequate hydration
• No specific long-term dietary modifications required after resolution

• GI: Nausea, vomiting, diarrhea (may indicate hemoperitoneum or MTX side effects)
• GU: Vaginal bleeding pattern, dysuria (rule out UTI as alternative cause of pelvic pain)
• Cardiovascular: Lightheadedness, syncope, palpitations (signs of hemorrhage)
• Respiratory: Dyspnea (rare — consider pneumonitis with MTX; also seen with massive hemorrhage)
• Musculoskeletal: Shoulder pain (referred pain from diaphragmatic irritation)
• Psychiatric: Anxiety, distress related to pregnancy loss

• Prior pregnancy outcomes, prior ectopic pregnancies (recurrence risk is significant) [1][9]
• History of pelvic inflammatory disease (PID), STIs (especially chlamydia) [1]
• Partner history of STIs
• Social support and ability to follow up reliably (critical for MTX management) [6]
• Family history of coagulopathy or thrombophilia (may affect bleeding risk)

• Prior ectopic pregnancy (strongest individual risk factor; recurrence ~10–15%) [1][9]
• History of PID or STIs (especially chlamydia/gonorrhea) [1]
• Prior tubal surgery (tubal ligation, salpingostomy, tubal reanastomosis) [1]
• Current IUD use (does not increase absolute risk, but if pregnancy occurs with IUD, higher proportion are ectopic)
• Cigarette smoking [1]
• Infertility and assisted reproductive technology (especially IVF) [1]
• Age >35 years [10]
• DES exposure in utero
• A significant proportion of patients will have no identifiable risk factor [10]

• Threatened/incomplete miscarriage — most common mimic; vaginal bleeding and pain more likely to indicate miscarriage than ectopic [2]
• Normal early intrauterine pregnancy with physiologic bleeding
• Ruptured or hemorrhagic ovarian/corpus luteum cyst
• Ovarian torsion
• Appendicitis — most common abdominal surgical emergency; right-sided pain overlap [4]
• Pelvic inflammatory disease
• Urinary calculus/pyelonephritis
• Heterotopic pregnancy (rare, ~1/30,000 spontaneous; higher with ART ~1/100) [2]
• Gestational trophoblastic disease

• Prior ectopic pregnancies and treatment method (medical vs. surgical)
• Prior pelvic/abdominal surgeries (adhesion risk)
• History of PID, endometriosis, or tubal pathology
• Hepatic or renal disease (contraindication to MTX) [9]
• Immunodeficiency or blood dyscrasias (contraindication to MTX)
• Pulmonary disease (risk of MTX-related pneumonitis) [9]

• Vitals: Tachycardia and hypotension suggest rupture/hemorrhage [2][5]
• Abdominal exam: Tenderness (often unilateral lower quadrant), guarding, rebound (peritoneal signs suggest rupture)
• Pelvic exam:
  • Cervical motion tenderness (CMT) — suggestive but nonspecific
  • Adnexal tenderness or palpable adnexal mass (small, round, tender, mobile swelling lateral to uterus) [2]
  • Cervical os: Closed os (open os with tissue suggests miscarriage)
  • Vaginal bleeding: Assess volume and character
• Expected in unruptured: Mild-to-moderate unilateral tenderness, minimal bleeding, stable vitals

• Quantitative serum β-hCG: Essential first step; serial levels q48h if pregnancy of unknown location [6][8]
  • Normal IUP: β-hCG rises ≥49–53% every 48 hours (depending on initial level) [8-9]
  • Rise <49% or abnormal decline suggests abnormal pregnancy (ectopic or early pregnancy loss) [8]
• CBC: Baseline hemoglobin; low Hgb may suggest occult hemorrhage [11]
• Blood type and Rh: For Rh immunoglobulin administration
• BMP/Cr, LFTs: Required before MTX administration [9]
• Progesterone: Low levels (<5 ng/mL) suggest nonviable pregnancy but do not localize it
• Urinalysis: Rule out UTI as alternative diagnosis

• First-line: Transvaginal ultrasound (TVUS) — single best diagnostic modality [2][12]
  • Definitive finding: Extrauterine gestational sac with yolk sac or embryo [6]
  • Suggestive findings: Inhomogeneous adnexal mass, "tubal ring" sign, extrauterine saclike structure [6][12]
  • Free pelvic fluid without IUP → suspect rupture [6-7]
  • TVUS sensitivity 99%, specificity 84% when β-hCG >1,500 IU/L [12]
  • Adnexal mass + no IUP → LR+ of 111 for ectopic pregnancy [2]
• Discriminatory zone: IUP should be visible on TVUS when β-hCG >3,000–3,500 mIU/mL (use conservative threshold to avoid interrupting viable IUP) [8][12]
• When imaging is nondiagnostic: Classify as "pregnancy of unknown location" (PUL) and follow with serial β-hCG and repeat TVUS [6]
• Transabdominal US: Supplement to assess for upper abdominal free fluid if rupture suspected [7]
• CT/MRI: Not routinely indicated; MRI may be useful for non-tubal ectopic locations

The following figure illustrates the diagnostic algorithm for evaluating pelvic pain in a patient who could be pregnant:

• Serial β-hCG monitoring: The cornerstone of diagnosis when TVUS is nondiagnostic; q48h until diagnosis confirmed [8]
• Uterine aspiration/curettage: Can differentiate failed IUP from ectopic — absence of chorionic villi suggests ectopic [9]
• Point-of-care ultrasound (POCUS): ED bedside TVUS can identify IUP or free fluid rapidly; absence of IUP with positive pregnancy test should prompt formal imaging and OB/GYN consultation [10]
• Culdocentesis: Largely replaced by ultrasound; historically used to detect hemoperitoneum

• Not routinely indicated for uncomplicated unruptured ectopic pregnancy
• Obtain ECG if: Hemodynamically unstable, syncope, or pre-operative evaluation
• Sinus tachycardia may be seen with hemorrhage/hypovolemia

Prevalence: 1–2% of all pregnancies; >90% are tubal (ampullary most common) [1][3]

Severity stratification

• Stable, unruptured: Hemodynamically stable, no peritoneal signs, β-hCG <5,000, mass <4 cm, no fetal cardiac activity → candidate for medical or surgical management [6]
• Unstable/ruptured: Hemodynamic instability, peritoneal signs, significant free fluid → emergent surgical management [5]

Typical presentation: Reproductive-age patient with amenorrhea (5–8 weeks), vaginal spotting, and unilateral pelvic pain. Many present atypically or are initially classified as PUL. [2]

Complications: Tubal rupture, hemorrhagic shock, infertility, recurrent ectopic pregnancy, psychological distress [13]

The following figure from the 2025 NEJM review outlines the treatment algorithm for stable tubal ectopic pregnancy:

Medical Management — Methotrexate [6][8]

• Eligibility criteria: Hemodynamically stable, unruptured, β-hCG <5,000 mIU/mL, mass <4 cm, no fetal cardiac activity, normal hepatic/renal function, reliable follow-up
• Single-dose protocol: MTX 50 mg/m² IM on day 1; check β-hCG on days 4 and 7
  • If ≥15% decline day 4→7: Weekly β-hCG until nonpregnant level
  • If <15% decline: Repeat MTX dose; if no decline after 2 doses → surgery
• Two-dose protocol: MTX 50 mg/m² IM on days 1 and 4; may be preferred when β-hCG >3,000 mIU/mL (higher success rate in this subgroup) [6][8]
• Success rate: ~70–89% depending on protocol and initial β-hCG [6]
• Median time to resolution: 22–28 days [6][14]
• Failure rate: 10–15%, requiring surgery [6]

Surgical Management [6][15]

• Laparoscopic salpingectomy: Definitive treatment; preferred in most cases
• Salpingostomy: Consider if contralateral tube is damaged and future fertility desired
• Indications for surgery: Patient preference, MTX contraindications, β-hCG >5,000, fetal cardiac activity, mass >4 cm, hemodynamic instability, MTX failure

Expectant Management [6][16]

• May be considered in highly selected patients: Hemodynamically stable, low and declining β-hCG (<1,000–2,000 mIU/mL), asymptomatic or minimal symptoms
• Success rate ~69% (vs. 79% with MTX); surgical intervention needed in ~19% [6]
• Requires close monitoring; abandon if symptoms develop or β-hCG fails to decline

• Discharge with outpatient follow-up: Hemodynamically stable, confirmed or suspected unruptured ectopic, reliable patient with access to follow-up, treated with MTX or expectant management [6][10]
• Admission/observation: Hemodynamic instability, significant pain, concern for impending rupture, inability to follow up, need for surgical management
• Emergent OB/GYN consultation: Hemodynamic instability, peritoneal signs, suspected rupture → immediate surgical intervention [8]
• Specialist consultation triggers: All confirmed ectopic pregnancies warrant OB/GYN involvement; PUL patients need close OB/GYN or early pregnancy unit follow-up

Post-MTX follow-up: [8]

• β-hCG on days 4 and 7 post-treatment, then weekly until undetectable (<5 mIU/mL)
• Resolution typically takes 2–4 weeks but can take up to 8 weeks [8]
• Avoid folic acid, NSAIDs, alcohol, and sexual intercourse during treatment
• Avoid new pregnancy until β-hCG fully resolved (wait at least one full menstrual cycle after resolution; some recommend 3 months)
• "Separation pain" (days 3–7 post-MTX) is common and usually self-limited; does not necessarily indicate rupture [9]

Return precautions — instruct patient to seek immediate care for:

• Severe or worsening abdominal pain
• Heavy vaginal bleeding (soaking >1 pad/hour)
• Lightheadedness, dizziness, syncope
• Shoulder pain
• Fever

Expected recovery: Most patients treated with MTX have complete resolution within 4 weeks. Subsequent fertility is not adversely affected by MTX treatment. [8] Recurrence risk of ectopic pregnancy is approximately 10–15% in future pregnancies. [1]

1. Ectopic Pregnancy: Diagnosis and Management. — Hendriks E, Rosenberg R, Prine L. American Family Physician. 2020.

2. Does This Woman Have an Ectopic Pregnancy?The Rational Clinical Examination Systematic Review. — Crochet JR, Bastian LA, Chireau MV. The Journal of the American Medical Association. 2013.

3. Combination of Gefitinib and Methotrexate to Treat Tubal Ectopic Pregnancy (GEM3): A Multicentre, Randomised, Double-Blind, Placebo-Controlled Trial. — Horne AW, Tong S, Moakes CA, et al. Lancet. 2023.

4. Evaluation of Acute Pelvic Pain in Women. — Frasca DJ, Jarrio CE, Perdue J. American Family Physician. 2023.

5. Ectopic Pregnancy. — Barnhart KT. The New England Journal of Medicine. 2009.

6. Tubal Ectopic Pregnancy. — Schreiber CA, Sonalkar S. The New England Journal of Medicine. 2025.

7. ACR Appropriateness Criteria® First Trimester Vaginal Bleeding: 2025 Update. — Expert Panel on GYN and OB Imaging, Laifer-Narin SL, Fruauff A, et al. Journal of the American College of Radiology : JACR. 2025.

8. ACOG Practice Bulletin No. 193: Tubal Ectopic Pregnancy. — Committee on Practice Bulletins—GynecologyThis Practice Bulletin was developed by the Committee on Practice Bulletins—Gynecology in collaboration with Kurt T Obstetrics and Gynecology. 2018.

9. Medical Treatment of Ectopic Pregnancy: A Committee Opinion. — Fertility and Sterility. 2013.

10. Updates in Emergency Medicine: Ectopic Pregnancy. — Jeffers K, Koyfman A, Long B. The American Journal of Emergency Medicine. 2024.

11. Risk Factors and Clinical Characteristics Associated With a Ruptured Ectopic Pregnancy: A 19-Year Retrospective Observational Study. — Li PC, Lin WY, Ding DC. Medicine. 2022.

12. ACR Appropriateness Criteria® Acute Pelvic Pain in the Reproductive Age Group: 2023 Update. — Brook OR, Dadour JR, Robbins JB, et al. Journal of the American College of Radiology : JACR. 2024.

13. Ectopic Pregnancy. — Chong KY, de Waard L, Oza M, et al. Nature Reviews. Disease Primers. 2024.

14. Time to Resolution of Tubal Ectopic Pregnancy Following Methotrexate Treatment: A Retrospective Cohort Study. — Davenport MJ, Lindquist A, Brownfoot F, et al. PloS One. 2022.

15. The Diagnosis and Management of Extrauterine and Uterine Ectopic Pregnancy. — Farren J, Al Wattar BH, Jurkovic D. Human Reproduction Update. 2025.

16. Methotrexate vs Expectant Management for Treatment of Tubal Ectopic Pregnancy: An Individual Participant Data Meta-Analysis. — Solangon SA, Van Wely M, Van Mello N, et al. Acta Obstetricia Et Gynecologica Scandinavica. 2023.