Placenta previa

Background

Normal placental anatomy.

Schematic of placenta previa.

Placenta previa subtypes.

• Placenta that extends near, partially over, or beyond the internal cervical os
  • Can be total, partial, or marginal
• Do NOT perform digital or speculum exam

Risk Factors

• Uterine scar
• Advanced maternal age
• Cigarette smoking
• Cocaine abuse

Clinical Features

• Painless vaginal bleeding in 3rd trimester
  • May be profuse, bright red

Differential Diagnosis

Abdominal Pain in Pregnancy

The same abdominal pain differential as non-pregnant patients, plus:

<20 Weeks

• Ectopic pregnancy
• First trimester abortion
  • Complete abortion
  • Threatened abortion
  • Inevitable abortion
  • Incomplete abortion
  • Missed abortion
  • Septic abortion
• Round ligament stretching
• Incarcerated uterus
• Malposition of the uterus

>20 Weeks

• Labor/Preterm labor
• Placental abruption
• Placenta previa
• Vasa previa
• Uterine rupture
• Vaginal trauma
• HELLP syndrome
• Cholestasis of pregnancy
• Chorioamnionitis
• Incarcerated uterus
• Acute fatty liver of pregnancy
• Malposition of the uterus
• Placenta accreta
• Placenta increta
• Placenta percreta

Any time

• Hemorrhagic ovarian cyst
• Fibroid degeneration or torsion
• Ovarian torsion
• Constipation

Evaluation

• Pelvic ultrasound - obtain position of placenta
• Type + cross
• Rho status
• CBC
• Coags
• Fetal Heart Monitoring

Management

• Requires cesarean- consult ob/gyn emergently
• Resuscitate

Dispo

• Admit

See Also

• Vaginal Bleeding (Main)