Illness script
Third-Trimester Antepartum Hemorrhage
Vaginal bleeding after 20 weeks gestation, classically from placenta previa (painless) or abruption (painful).
This illness script for Third-Trimester Antepartum Hemorrhage covers the classic presentation, who it affects, how you work it up, the mechanism, and first-line treatment—written for USMLE Step 1 and clerkship clinical reasoning.
Updated Jul 18, 2026All scripts
01
Who it affects
- Multiparity, advanced maternal age
- Prior cesarean/uterine surgery (previa, accreta)
- Hypertension, trauma, cocaine use (abruption)
- Prior abruption or previa, smoking
- Multiple gestation, polyhydramnios
02
Diagnostics & workup
- NEVER perform digital vaginal exam until previa excluded
- Previa: painless bright-red bleeding; abruption: painful dark bleeding, tender rigid uterus
- Transabdominal/transvaginal ultrasound to locate placenta
- Continuous fetal heart monitoring + tocodynamometry
- CBC, type & screen/crossmatch, coags, fibrinogen, Kleihauer-Betke
- Abruption is a clinical diagnosis; US often normal (can't exclude)
03
Pathophysiology
- Placenta previa: placenta covers/near internal cervical os
- Abruption: premature separation of placenta from decidua, retroplacental hematoma
- Vasa previa: fetal vessels cross os, rupture causes fetal exsanguination
- Abruption can trigger DIC via thromboplastin release
- Concealed vs revealed hemorrhage in abruption
04
Treatment
- ABCs, two large-bore IVs, fluids, transfuse as needed
- Continuous fetal monitoring; assess maternal hemodynamics
- Rh-negative mothers: give anti-D immunoglobulin
- Stable preterm: expectant management, steroids for lung maturity, possible tocolysis
- Delivery for maternal/fetal instability, term, or severe abruption
- Previa or vasa previa: scheduled cesarean; emergent C-section if unstable
Keep reading
Full library- Stress Urinary IncontinenceLeakage of urine with coughing, sneezing, laughing, or exertion, typically in a multiparous or postmenopausal woman.
- TrichomoniasisSexually active woman with frothy, malodorous yellow-green discharge and a 'strawberry cervix'.
Educational use only. This illness script is a study framework, not medical advice. Confirm decisions with current guidelines and your clinical supervisors.