Harvey's Garden

Pregnancy loss

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aliasesspontaneous abortion

6 min read

Epidemiology & Risk Factors

  • Epidemiology:
    • Most common early pregnancy complication (10–20% of recognized pregnancies).
    • &gt 80% occur during the 1st trimester (<12 weeks gestation).
  • Etiology:
    • Fetal Chromosomal Aneuploidy (~50% of 1st trimester losses): Autosomal trisomy is the #1 most common overall (Trisomy 16 most frequent); Monosomy X (45,XO / Turner syndrome) is the single most common specific chromosomal defect.
  • Risk Factors:
    • Advanced Maternal Age (AMA >35 yo): Single greatest non-genetic risk factor.
    • Prior history of spontaneous abortion (risk increases exponentially with each consecutive loss).
    • Maternal endocrine disorders: Uncontrolled DM2, overt hypothyroidism/Hashimoto, PCOS.
    • Anatomical defects: Uterine septum (highest miscarriage rate), submucosal leiomyomas, intrauterine adhesions (Asherman syndrome).
    • Immunologic/Thrombophilic: Antiphospholipid Syndrome (APS), systemic lupus erythematosus (SLE).
    • Behavioral/Environmental: Tobacco, alcohol, cocaine, severe maternal malnutrition.
    • Cervical insufficiency (typically causes painless 2nd-trimester losses).

Clinical Features

TypeBleeding?Cervical OsTVUS / Fetal Cardiac ActivityManagement
Threatened(+)ClosedViable (FHR present)Expectant, pelvic rest, serial TVUS
Inevitable(+)OpenNonviable / Ruptured membranesExpectant, medical, or surgical
Incomplete(+)OpenRetained POCMedical or surgical evacuation
Complete(+/-) (resolved)ClosedEmpty uterusFollow -hCG to negative
Missed(-)ClosedNonviable / No progressionExpectant, medical, or surgical
Septic(+), malodorousOpen + boggyRetained POC + infection signsIV Abx + Urgent D&C
  • General Presentation: Vaginal bleeding, lower midline abdominal/pelvic cramping, passage of products of conception (POC), regression of pregnancy symptoms (nausea, breast tenderness).
  • Classification by Clinical Subtype:
    • Threatened Abortion:
      • History: Vaginal bleeding/spotting ± mild cramping.
      • Speculum/Bimanual: Closed cervical os.
      • Ultrasound: Fetal cardiac activity present (viable IUP).
    • Inevitable Abortion:
      • History: Moderate-to-severe vaginal bleeding, painful uterine contractions.
      • Speculum/Bimanual: Dilated/open cervical os, membranes may bulge; no tissue passed yet.
      • Ultrasound: Gestational sac low/collapsed; nonviable or viable IUP.
    • Incomplete Abortion:
      • History: Heavy bleeding, severe cramping, partial passage of tissue.
      • Speculum/Bimanual: Dilated/open cervical os with visible POC in the canal/vagina.
      • Ultrasound: Retained POC, thickened/irregular endometrial stripe.
    • Complete Abortion:
      • History: Prior heavy bleeding and cramping that have now markedly improved after passage of a complete gestational sac/clot.
      • Speculum/Bimanual: Closed cervical os, minimal bleeding, firm/contracted uterus.
      • Ultrasound: Empty uterine cavity, thin endometrial stripe (<5 mm).
    • Missed Abortion:
      • History: Asymptomatic or regression of pregnancy symptoms; no active bleeding (or light brownish spotting), no cramping.
      • Speculum/Bimanual: Closed cervical os.
      • Ultrasound: Retained nonviable embryo/fetus (no fetal heart activity) or empty gestational sac (anembryonic pregnancy / blighted ovum). c
    • Septic Abortion: The death of a fetus before 20 weeks’ gestation without expulsion of any products of conception.
      • History: Severe pelvic pain, fever/chills, malodorous vaginal discharge; often post-unsterile instrumentation.
      • Speculum/Bimanual: Foul-smelling/purulent discharge, cervical motion tenderness (CMT), marked uterine tenderness; open or closed os.
      • Systemic: Tachycardia, hypotension, leukocytosis (signs of sepsis/SIRS).

Diagnosis

  • Initial / Best Imaging: Transvaginal Ultrasound (TVUS)
    • Assesses location (rule out ectopic) and fetal viability.
    • Diagnostic criteria for nonviable IUP:
      • Crown-rump length (CRL) ≥7 mm with no fetal heart rate (FHR).
      • Mean sac diameter (MSD) ≥25 mm without an embryo.
  • Key Labs:
    • Maternal Blood Type & Rh(D) Screen: Mandatory in all patients with bleeding in pregnancy to assess need for Rho(D) immune globulin (RhoGAM).
    • Quantitative serum β-hCG: Serial levels every 48 hours if TVUS is indeterminate. Nonviable IUP demonstrates subnormal rise (<35% in 48h) or plateau/decline.
    • CBC, Type & Screen/Cross: If heavy vaginal bleeding or hemodynamic instability.
    • Coagulation studies (PT/INR, PTT, Fibrinogen): If septic abortion or prolonged retention of missed abortion (risk of DIC).
  • Confirmatory / Pathology:
    • Histopathological examination of expelled/curetted tissue demonstrating chorionic villi (confirms IUP, excludes complete molar pregnancy and ectopic pregnancy).
  • Recurrent Pregnancy Loss (RPL) Workup (≥2 consecutive clinical pregnancy losses):
    • Parental karyotyping.
    • Uterine cavity assessment: Hysterosalpingography (HSG), Sonohysterography, or Hysteroscopy.
    • Antiphospholipid Antibody Panel: Lupus anticoagulant, Anticardiolipin antibodies (IgG/IgM), Anti-β2-glycoprotein-I.
    • Endocrine: TSH, HbA1c, prolactin.

Differential Diagnostics

  • Ectopic Pregnancy:
    • Differentiating features: Empty uterus on TVUS with β-hCG above discriminatory zone (>1500–2000 mIU/mL), adnexal mass (“bagel/tubal ring sign”), adnexal tenderness, fluid in pouch of Douglas.
  • Hydatidiform Mole (Gestational Trophoblastic Disease):
    • Differentiating features: Markedly elevated β-hCG (>100,000 mIU/mL), hyperemesis gravidarum, early preeclampsia (<20 weeks), “snowstorm” / “Swiss cheese” appearance on TVUS, bilateral theca lutein cysts.
  • Cervical Insufficiency:
    • Differentiating features: Painless cervical dilation and effacement in the 2nd trimester without uterine contractions or significant bleeding; bulging amniotic membranes (“hourglassing”).
  • Intrauterine Fetal Demise (IUFD / Stillbirth):
    • Differentiating features: Fetal death occurring at ≥20 weeks gestation (vs. spontaneous abortion at <20 weeks); absent fetal movement and absence of cardiac activity on ultrasound.
  • Physiologic Implantation Bleeding:
    • Differentiating features: Light, self-limited spotting around the time of expected menses; normal doubling of serial β-hCG; no cramping; closed os.

Management

  • Emergency / Hemodynamically Unstable / Septic / Heavy Hemorrhage:
    1. ABC & Resuscitation: 2 large-bore IVs, IV crystalloid bolus, Type & Crossmatched blood transfusion (activate MTP if severe).
    2. Immediate Surgical Evacuation: Suction Dilation & Curettage (D&C) or Manual Vacuum Aspiration (MVA).
    3. Septic Abortion Additions: Broad-spectrum IV antibiotics (Ampicillin + Gentamicin + Metronidazole OR Clindamycin + Gentamicin) followed by prompt D&C to remove the infected nidus.
  • Hemodynamically Stable Patients (Early Loss: Missed, Incomplete, Inevitable):
    • Expectant Management:
      • Indications: Patient preference, stable, minimal symptoms, GA <13 weeks.
      • Observation for up to 2–4 weeks; monitor with serial TVUS/β-hCG.
    • Medical Management:
      • Regimen: Mifepristone (progesterone antagonist) 200 mg PO followed 24 hours later by Misoprostol (PGE1 analog) 800 mcg vaginally/buccally (or Misoprostol alone).
      • Hastens expulsion; avoids invasive surgery.
    • Surgical Management:
      • Indications: Patient preference, persistent/heavy bleeding, failed medical/expectant therapy, infection.
      • Procedure: Suction D&C or MVA under local/sedation.
  • Threatened Abortion:
    • Expectant management, outpatient pelvic rest, reassurance.
    • Serial β-hCG and repeat TVUS in 7–14 days.
  • Universal Step for All Non-Sensitized Rh-Negative Mothers:
    • Administer Rho(D) Immune Globulin (RhoGAM) within 72 hours of bleeding event:
      • 50 mcg if GA ≤12 weeks.
      • 300 mcg if GA >12 weeks.
  • Etiology-Specific Prevention in RPL:
    • Antiphospholipid Syndrome (APS): Low-dose aspirin (ASA) + prophylactic LMWH (heparin).
    • Uterine Septum: Hysteroscopic septoplasty.
    • Cervical Insufficiency: Prophylactic cervical cerclage placed electively at 12–14 weeks GA.

Complications

  • Hemorrhagic shock and severe anemia requiring transfusion.
  • Septic abortion → Pelvic peritonitis, septic shock, multi-organ dysfunction syndrome (MODS).
  • Disseminated Intravascular Coagulation (DIC): Triggered by release of fetal/placental tissue factor into maternal circulation (high risk in prolonged retained dead fetus >4 weeks or septic abortion).
  • Asherman Syndrome: Intrauterine synechiae secondary to aggressive curettage during D&C → secondary amenorrhea and infertility.
  • Uterine perforation / Cervical laceration during surgical instrumentation.
  • Rh(D) Alloimmunization: If RhoGAM is omitted in Rh-negative patients → hydrops fetalis in subsequent pregnancies.
  • Psychological sequelae: Postpartum depression (PPD), Major Depressive Disorder (MDD), Post-Traumatic Stress Disorder (PTSD), and complicated grief.

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