Antepartum hemorrhage

Placental abruption

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The partial or complete separation of the placenta from the uterus prior to delivery; subsequent hemorrhage occurs from both maternal and fetal vessels.

Epidemiology

• Occurs most often in the third trimester

Etiology

• Pathophysiology: Premature detachment of placenta from uterine decidua before fetal delivery $\to$ rupture of maternal spiral arteries $\to$ decidual hematoma.
• Major Risk Factors:
  • Maternal HTN / Preeclampsia / Chronic HTN (strongest overall predictor). c
  • Abdominal trauma (e.g., MVA, domestic violence) / Rapid uterine decompression (e.g., ROM in polyhydramnios, delivery of twin A).
  • Cocaine or amphetamine use (vasospasm $\to$ ischemia).
  • Tobacco smoking.
  • Prior history of placental abruption.
  • Advanced maternal age (AMA) and high parity.
  • Uterine anomalies, leiomyomas (especially submucosal).

Clinical features

• Classic Presentation: Painful 3rd-trimester vaginal bleeding + hypertonic, tender uterus (“woody” abdomen) + high-frequency contractions (tachysystole).
• Concealed Abruption (~20%): Bleeding is entirely retroplacental; no visible vaginal bleeding, but severe abdominal pain, uterine hypertonus, and maternal hemodynamic instability are present. c
• Fetal Tracing: Fetal distress (loss of variability, recurrent late decelerations, bradycardia, sinusoidal pattern).
• PE: Uterine tenderness on palpation, elevated resting uterine tone, maternal hypotension/tachycardia.

Management

1. Stabilization (Immediate):
   • 2 large-bore IVs, aggressive IVF, crossmatched PRBCs/FFP/cryo, O2, left lateral tilt.
   • Administer Rh(D) immune globulin if Rh-negative.
2. Emergency C-Section:
   • Indicated for maternal hemodynamic instability, DIC, or non-reassuring FHR.
3. Vaginal Delivery:
   • Indicated if mother and fetus are stable with term/rapidly progressing labor.
4. Expectant Management:
   • Preterm (< 34 weeks), mild/stable abruption, reassuring FHR; give antenatal steroids (betamethasone).

Placenta previa

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Presence of the placenta in the lower uterine segment, which can lead to partial or full obstruction of the internal os; high risk of hemorrhage (rupture of placental vessels) and birth complications

Risk factors

• Maternal age > 35 years, multiparity, short intervals between pregnancies
• Previous curettage or cesarean delivery
• Previous placenta previa, previous/recurrent abortions

Classification

• Placenta previa: placenta either partially or completely covers the internal os
  • Previously, this category included marginal previa (placenta reaching the internal os), partial previa (placenta partially covering the internal os), and complete previa (placenta completely covering the internal os); these terms have been excluded from the new classification.
• Low-lying placenta: lower edge of the placenta lies less than 2 cm from the internal cervical os

Clinical features

• Sudden, painless, bright red vaginal bleeding
• Usually occurs during the 3rd trimester (before rupture of the membranes)
• Initial bleeding episodes are often self-limited and recur during the onset of labor
• Soft, nontender uterus
• Usually no fetal distress

Treatment

• Asymptomatic/Stable: Expectant management with pelvic rest (no intercourse, no digital exams), and serial ultrasounds. Corticosteroids (e.g., betamethasone) are given for fetal lung maturity if <34 weeks.
• Active Bleeding:
  • Unstable mother or fetus: Immediate C-section regardless of gestational age.
  • Stable mother and fetus (>36 weeks): Scheduled C-section is the standard mode of delivery.
• Never deliver vaginally if there’s a complete previa.
• IV access with large-bore cannulas, blood type and crossmatch are essential due to hemorrhage risk.

Vasa previa

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• Definition & Pathophysiology: Unprotected fetal blood vessels traverse membranes over the internal cervical os without Wharton jelly support (high risk of rupture/compression).
• Risk Factors: Velamentous cord insertion, succenturiate/accessory lobe, low-lying placenta, IVF, twins.
• Clinical Presentation (Classic Triad):
  • Painless vaginal bleeding
  • Triggered by rupture of membranes (ROM)
  • Fetal distress (fetal bradycardia, sinusoidal FHR pattern) w/ stable maternal vitals.
• Diagnosis:
  • Prenatal/Gold Standard: TVUS w/ Color Doppler (shows fetal vessels directly overlying/within 2 cm of os).
  • Intrapartum: Apt test or Wright stain (detects fetal HbF vs maternal HbA; usually skipped for immediate delivery).
• Differential Diagnosis: c
  • Placenta Previa: Painless bleeding before ROM; maternal origin (maternal shock); normal initial FHR.
  • Placental Abruption: Painful bleeding + uterine tenderness/hypertonus.
  • Uterine Rupture: Severe abdominal pain, loss of fetal station, maternal collapse, prior C-section scar.
• Management:
  • Prenatal (Diagnosed early): Hospitalize at 30–34 wks -> Antenatal corticosteroids -> Elective C-section at 34–35 wks.
  • Emergency (Active bleeding / ROM / Fetal distress): Immediate Emergency C-section + prepare O-neg PRBCs for neonatal transfusion.