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This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.
The Bottom Line
- Spontaneous abortion = pregnancy loss before 20 weeks; most first-trimester losses are due to fetal chromosomal abnormalities
- Threatened abortion = bleeding with closed cervix and viable intrauterine pregnancy
- Inevitable/incomplete abortion = open cervix; incomplete has retained products
- Stable early pregnancy loss can be managed expectantly, medically, or surgically
- Septic abortion = fever, uterine tenderness, foul discharge, or sepsis → IV antibiotics + evacuation
Overview
Early pregnancy loss must be distinguished from ectopic pregnancy in any patient with first-trimester bleeding or pain. Classification depends on cervical os status, fetal cardiac activity, and retained products. Stable patients can usually choose expectant, medical, or surgical management.
Epidemiology
Clinically recognized early pregnancy loss occurs in about 10% of pregnancies and increases with maternal age. Chromosomal aneuploidy accounts for about half of first-trimester losses. Recurrent pregnancy loss prompts targeted evaluation.
Clinical Features
Symptoms
First-trimester vaginal bleeding
Crampy lower abdominal or pelvic pain
Passage of tissue or clots
Fever, chills, foul discharge, or severe pelvic pain
Syncope or rapidly soaking pads
Signs
Closed cervical os with viable IUP = threatened abortion
Open cervical os = inevitable or incomplete abortion
Products of conception at cervical os
Uterine tenderness, fever, or purulent discharge suggests septic abortion
Hemodynamic instability suggests hemorrhage or ruptured ectopic
Investigations
First-line
Transvaginal ultrasoundConfirms intrauterine location and viability; CRL >=7 mm without heartbeat or mean sac diameter >=25 mm without embryo is diagnostic
Quantitative beta-hCGSerial testing if ultrasound is indeterminate or pregnancy location is unknown
CBC, blood type/Rh, antibody screenAssess anemia and Rh(D) immune globulin need
Second-line
Products of conception pathologyConfirms intrauterine pregnancy tissue after evacuation when location was uncertain
Infection evaluationCBC, cultures, lactate, and ultrasound if septic abortion suspected
Recurrent loss workupAntiphospholipid antibodies, uterine cavity assessment, TSH, HbA1c, and karyotypes when indicated
Specialist
Uterine aspirationDiagnostic and therapeutic when bleeding is heavy, infection suspected, or rapid resolution desired
Genetic testing of tissueConsider in recurrent pregnancy loss when results affect counseling
1
Initial stabilization
- Assess hemodynamic status and bleeding severity
- Exclude ectopic pregnancy if IUP has not been confirmed
- Speculum exam for os status and tissue
- Give Rh(D) immune globulin to Rh-negative unsensitized patients
2
Expectant management
- Appropriate for stable first-trimester patients without infection or hemorrhage
- Most effective for incomplete abortion
- Provide analgesia, bleeding precautions, and follow-up
3
Medical management
- Mifepristone followed by misoprostol is more effective than misoprostol alone when available
- Misoprostol alone is accepted when mifepristone unavailable
- Counsel on heavy bleeding, cramping, and follow-up
4
Surgical management
- Uterine aspiration/suction curettage for instability, heavy bleeding, infection, anemia, preference, or failed other management
- Septic abortion requires IV antibiotics plus evacuation
Complications
- Hemorrhage: May require urgent evacuation and transfusion
- Septic abortion: Requires IV antibiotics and evacuation
- Retained products: Persistent bleeding or plateauing beta-hCG
- Asherman syndrome: Intrauterine adhesions after curettage
- Psychological distress: Requires sensitive counseling
USMLE Step 2 CK Exam Tips
- 1Threatened abortion = bleeding + closed os + fetal cardiac activity → reassurance/follow-up
- 2Open cervical os = inevitable or incomplete abortion
- 3Fever + uterine tenderness + foul discharge = septic abortion
- 4Do not diagnose miscarriage on equivocal ultrasound; repeat imaging/beta-hCG
- 5Rh-negative bleeding or pregnancy loss = Rh(D) immune globulin
- 6Most common first-trimester miscarriage cause = chromosomal abnormality
- 7Stable early pregnancy loss: expectant, medical, or surgical based on preference
practicetest your knowledge on spontaneous abortion (miscarriage)Apply what you've learnt with USMLE Step 2 CK-style questions from the iatroX Q-Bank — obstetrics & gynecology and beyond.
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