Early Pregnancy Loss

Aka: Early Pregnancy Loss, Spontaneous Abortion, Miscarriage, Inevitable Abortion, Missed Abortion, Septic Abortion, Incomplete Abortion, Complete Abortion, Blighted Ovum, Embryonic Resorption, Subchorionic Hemorrhage, Threatened Abortion, Decidua, Decidual Cyst, Postabortion Hemorrhage

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II. Epidemiology

  1. Incidence Miscarriage (U.S.): 20% of pregnancies (most by 12 weeks gestation)
  2. Incidence of First Trimester Bleeding: 25-30%
    1. Miscarriage occurs in 50% of bleeding cases
    2. Even if viable, higher complication risk post-bleed

III. Definitions

  1. Spontaneous Abortion (Miscarriage)
    1. Gestational Age <20 weeks, fetal weight <500 grams
    2. Considered early spontaneous pregnancy loss if <13 weeks
  2. Inevitable Abortion
    1. Bleeding and rupture of Gestational Sac <20 weeks
    2. Cervix dilated
    3. Menstrual-type cramping
    4. No products of conception expelled yet
  3. Missed Abortion (Fetal Demise, Embryonic Demise)
    1. Embryo >7 mm without fetal heart activity
    2. Retained non-viable conception products up to 4 weeks
  4. Septic Abortion
    1. Incomplete Abortion with secondary ascending infection
    2. Results in Endometritis, parametritis or peritonitis
  5. Incomplete Abortion
    1. Incomplete evacuation of products of conception
  6. Complete Abortion
    1. Complete evacuation of products of conception
    2. Difficult to differentiate from Incomplete Abortion
      1. May require dilatation and curettage for diagnosis
  7. Blighted Ovum (Embryonic Resorption, Anembryonic Pregnancy)
    1. Gestational Sac (>25 mm) and placenta present
    2. Failure of Embryo to develop (no Yolk Sac or Embryo)
  8. Subchorionic Hemorrhage
    1. Blood collected between chorion and uterine wall
  9. Threatened Abortion
    1. Uterine bleeding before 20 weeks (often accompanied by abdominal cramping)
    2. Cervix closed
    3. Ultrasound with intrauterine pregnancy (typically, Embryo with fetal heart activity)
    4. Risk of Complete Abortion: 50%
  10. Decidua
    1. Pregnancy endometrium passed with Miscarriage
    2. Consider Ectopic Pregnancy if passed intact
      1. Known as Decidual Cyst
  11. Induced Abortion
    1. Elective Abortion or
    2. Therapeutic Abortion

IV. Causes: Spontaneous Abortion

  1. Autosomal Trisomy (most common Miscarriage etiology)
  2. Chromosomal Triploidy or Monosomy
  3. Uterine anomaly (e.g. Leiomyoma, DES Exposure)
  4. Incompetent Cervix
  5. Progesterone deficiency (late Luteal Phase defect)
  6. Environmental factors
    1. See risk factors below

V. Risk Factors: Associated with Spontaneous Abortion

  1. See Ectopic Pregnancy for associated risk factors
  2. Advanced maternal age
  3. Cigarette smoking increases risk of euploidic abortion
    1. Over 14 Cigarettes/day doubles risk over non-smokers
    2. Relative Risk increases 1.2x for each 10 cigs/day
  4. Alcohol Abuse increases risk of euplodic abortion
    1. Abortion risk doubled for twice weekly Alcohol
    2. Abortion risk tripled for daily Alcohol use
  5. Illicit Drug Use
  6. Occupational chemical exposure
  7. Caffeine may be associated with Miscarriage (variable evidence)
    1. Small amounts of Caffeine are safe in pregnancy
    2. Limit Caffeine intake to 200 mg/day (e.g. 12 ounces coffee)
    3. Be aware of all potential Caffeine sources
    4. Cnattingius (2000) N Engl J Med 343(25):1839-45 [PubMed]
    5. Savitz (2008) Epidemiology 19(1):55-62 [PubMed]
  8. Uterine surgeries or anomalies
  9. Incompetent Cervix
  10. Diabetes Mellitus (Uncontrolled)
  11. Progesterone deficiency
  12. Thyroid disease
  13. Connective Tissue Disorder
    1. Systemic Lupus Erythematosus
    2. Antiphospholipid Antibodies
      1. Lupus Anticoagulant
      2. Anticardiolipin Antibodies

VI. Myths: Factors not associated with pregnancy loss

  1. Stress
  2. Sexual activity
  3. Air Travel
  4. Exercise
  5. Contrceptive use
  6. HPV Infection

VII. Evaluation

  1. See First Trimester Bleeding
  2. Ultrasound findings suggestive of nonviable pregnancy
    1. Crown-Rump Length >= 7mm without a fetal heart beat
    2. Mean Gestational Sac diameter >=25 mm without a fetal pole or Embryo
    3. Embryo absent with heartbeat
      1. Repeat Ultrasound >=2 weeks after scan with Gestational Sac WITHOUT Yolk Sac
      2. Repeat Ultrasound >=11 days after a scan with Gestational Sac AND Yolk Sac

VIII. Management: Threatened Abortion

  1. Maximize Hydration
    1. Intravenous isotonic crystalloid
    2. Oral hydration if tolerated
  2. Give RhoGAM if mother is Rh Negative (50 or 120 mcg at <12 weeks if available, otherwise 300 mcg)
    1. RhoGAM is NOT required for Miscarriage or abortion <12 weeks gestation per ACOG 2024
      1. However, RhoGAM is still recommended in Ectopic Pregnancy <12 weeks or when dates are uncertain
      2. (2024) Obstet Gynecol 144(6):e140-3 +PMID: 39255498 [PubMed]
    2. RhoGAM is given within 72 hours of Abdominal Trauma, Ectopic Pregnancy, uterine aspiration
    3. In threatened Ab, most providers do not give RhoGAM for spotting, only for significant bleeding (or Ectopic Pregnancy)
    4. Karanth (2013) Cochrane Database Syst Rev (3):CD009617 [PubMed]
  3. Disposition: Expectant management
    1. Oral hydration
    2. Pelvic rest (including abstaining from intercourse)
    3. Precautions for return
    4. Close interval follow-up with obstetrics provider
    5. Repeat Transvaginal Ultrasound in 7-14 days

IX. Management: Inevitable, incomplete or Complete Abortion

  1. Precautions
    1. Medication or procedure is needed in 20% of Miscarriages
    2. Incomplete Abortion requires prompt obstetric evaluation
      1. Risk of Septic Abortion or Hemorrhage with delay
  2. General
    1. Consider intravenous hydration
    2. Consider complications (e.g. Septic Abortion)
    3. Give RhoGAM if mother is Rh Negative (see above)
    4. Follow serial Quantitative hCGs until 0
  3. Observation Indications (effective in 85-90% of cases; only 66-76% in anembryonic gestation, Embryonic demise)
    1. Gestational Age under 8 weeks
    2. Most first trimester losses may pass spontaneously
    3. Stable patient
  4. HCG monitoring indications (followed to <5 mIU/ml if indicated)
    1. Completed abortion not confirmed
    2. Resolving pregnancy of unknown location (risk of Ectopic Pregnancy)
    3. Possible Gestational Trophoblastic Disease (Abnormal Uterine Bleeding, malignancy suspected)
  5. Ultrasound Indications
    1. Confirm Early Pregnancy Loss (see above)
    2. Confirm intrauterine pregnancy (not Ectopic Pregnancy)
    3. Assess Gestational Age
      1. Medical management is appropriate for Gestational Age <13 weeks gestation
  6. Misoprostol and Mifepristone (preferred)
    1. See Mifepristone and Misoprostol Protocol for Early Pregnancy Loss
  7. Misoprostol Alone
    1. Other dosing in first trimester Miscarriage
      1. Vaginal: 800 mcg intravaginally for 1 dose (may be repeated after 3 days if not effective)
      2. Oral: 600 mcg orally for 1 dose (may be repeated after 3 days if not effective)
    2. Efficacy
      1. Misoprostol alone (70% success rate)
        1. Best efficacy is when combined with Mifepristone (85% success rate)
      2. Highly effective in missed Spontaneous Abortion (esp. anembryonic gestation, Embryonic demise)
        1. Wood (2002) Obstet Gynecol 99:563-6 [PubMed]
      3. No benefit in incomplete Spontaneous Abortion
        1. Nielsen (1999) Br J Obstet Gynaecol 106:804-7 [PubMed]
      4. Completes first trimester Spontaneous Abortion within 2 weeks: 66%
        1. Blanchard (2004) Obstet Gynecol 103:860-5 [PubMed]
  8. Dilatation and Curettage (or Dilatation and Evacuation, or Uterine Aspiration)
    1. See Manual Uterine Aspiration in First Trimester Pregnancy Loss
    2. Indications
      1. Gestational Age 8 to 14 weeks
      2. Excessive intrauterine bleeding (>1 pad/hour) or pain
      3. Prolonged symptoms or delayed passage of tissue
      4. Confirm intrauterine pregnancy (chorionic villi)
  9. Delivery options for 14-20 weeks gestation
    1. Pitocin
      1. Prepare 40 units/Liter in D5LR
      2. Start at 1 mu and double rate every 20-30 minutes
      3. Endpoint
        1. Contractions adequate
        2. Hyperstimulation
    2. Prostaglandin (PG) Cervical Ripening
      1. PGE2 intravaginal suppository
        1. Dose: 20 mg suppository intravaginally
        2. Insert q3 hours until contractions adequate
      2. PG F2 alpha intraamniotic preparation
        1. Test-Dose: 6 mg (6 mg/ml)
        2. Actual Dose: 40 mg vial slowly

X. Management: Intrauterine Bleeding

  1. Typical bleeding
    1. Remove products at Cervix (helps to decrease bleeding by allowing cervical os to close)
    2. Intravenous Normal Saline with 30u Pitocin/Liter at 200 cc/hour
    3. Methergine 0.2 mg orally four times daily for 6 doses as needed for bleeding
  2. Post-Spontaneous Abortion Hemorrhage
    1. Similar management to Postpartum Hemorrhage
      1. Maximize uterine tone (uterine massage)
      2. Evaluate for uterine or Vaginal Trauma (e.g. cervical or vaginal Laceration)
        1. Consult gynecology for definitive repair
        2. Figure-of-eight Suture may be used to stabilize focal bleeding until definitive repair
      3. Evaluate for retained products (including clot or tissue in the cervical os)
        1. Removing clot from the cervical os may help stabilize heavy uterine bleeding
      4. Consider Coagulopathy (e.g. DIC)
    2. Perform typical bleeding measures as above
    3. Acute stabilization
      1. ABC Management
      2. Obtain 2 large bore IVs (14-16 gauge)
      3. Transfusion Packed Red Blood Cells (start with O negative or type specific blood)
        1. Activate Massive Transfusion Protocol if >2 units pRBC required
    4. Uterotonic Medications
      1. Misoprostol (Cytotec)
        1. Administer1000 mcg per cervical os or Rectum
        2. Alternatively 400 to 800 mcg in buccal space of mouth may be used
      2. Methyl-ergonovine (Methergine) 0.2 mg IV
      3. Carboprost (Hemabate) 250 mcg IM
      4. Oxytocin
        1. Typically ineffective at gestation age <20 weeks
        2. Dosing: 20 to 40 units in 500 ml NS
    5. Emergency obstetrics Consultation
      1. Consider Emergent dilatation and curettage (D & C)
    6. Other temporizing measures
      1. Vaginal packing with moist sterile gauze may be attempted for vaginal packing
      2. Bakri Balloon tamponade of Uterus
        1. If unavailable may use Foley Catheter inflated within Uterus
      3. Consider Tranexamic Acid 1000 mg IV
      4. Consider Vasopressin if suspected or known Von Willebrand Disease
  3. References
    1. Herbert and Cardy in Herbert (2017) EM:Rap 17(6):4
    2. Swaminathan and Shoenberger (2023) EM:Rap 23(11)

XI. Management: Post-Pregnancy Loss Care

  1. See Grief in Pregnancy Loss
  2. Contraception may start immediately (unless patient wishes to try to conceive)
  3. Conception desired
    1. Take Folic Acid supplementation
    2. No need to delay repeat attempt at pregnancy
      1. In fact, chance of pregnancy is higher within 3 months of Early Pregnancy Loss
      2. Sundermann (2017) Obstet Gynecol 130(6): 1312-18 [PubMed]

XII. Complications

  1. Septic Abortion (septic Miscarriage, Endometritis)
    1. See Endometritis Antibiotic Management
    2. Consider with significant uterine tenderness, fever, foul lochia
  2. Hemorrhage (see above)
  3. Rh Sensitization (risk of Fetal hydrops)
    1. Prevent with RhoGAM administration

XIII. References

  1. Orman and Glaser in Herbert (2017) EM:Rap 17(2): 13-4
  2. Simpson in Gabbe (2002) Obstetrics, p. 729-44
  3. Stenchever (2001) Gynecology p. 156-7
  4. Deutchman (2009) Am Fam Physician 79(11): 985-92 [PubMed]
  5. Hendriks (2019) Am Fam Physician 99(3): 166-74 [PubMed]
  6. MacNaughton (2021) Am Fam Physician 103(8) 473-80 [PubMed]
  7. Nadukhovskaya (2001) Am J Emerg Med 19(6):495-500 [PubMed]
  8. Paspulati (2004) Radiol Clin North Am 42(2):297-314 [PubMed]
  9. Prine (2011) Am Fam Physician 84(1): 75-82 [PubMed]

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