Placenta previa vs Placental abruption, vasa previa, and uterine rupture
How to tell Placenta previa and Placental abruption, vasa previa, and uterine rupture apart when a board question makes them look alike.
Previa: painless bleeding with placenta over the os; abruption: painful tender uterus; vasa previa: ROM with bleeding and fetal bradycardia; rupture: scar pain with fetal distress.
Side by side
Placenta previa causes painless third-trimester vaginal bleeding with placenta covering or near the cervical os.
Abruption causes painful bleeding with uterine tenderness; vasa previa causes painless bleeding with fetal bradycardia after membrane rupture, especially with velamentous cord insertion or succenturiate/bilobed placenta; uterine rupture causes acute pain, fetal distress, and loss of station.
A low-lying placenta overlies the cervical os and bleeds as the cervix changes in late pregnancy.
Abruption is premature placental separation; vasa previa is fetal vessel rupture; uterine rupture is tearing of the uterine wall, often at a scar.
Ultrasound showing placenta over the os and painless bleeding support previa; digital cervical exam is avoided until location is known.
Tender rigid uterus supports abruption; painless bleeding plus fetal bradycardia after rupture of membranes supports vasa previa; prior uterine surgery and lost station support rupture.
The trap
All can bleed late in pregnancy, so pain, uterine tone, fetal status, membrane rupture, and placental location separate them.
The repair move
For late pregnancy bleeding, decide pain versus painless, maternal versus fetal bleeding, and whether a uterine scar is involved.
Try a free question
CoreA 32-year-old G2 P1 at 30 weeks gestation has sudden painless bright-red vaginal bleeding without contractions. The uterus is soft and nontender. Fetal heart tracing is reassuring. Transabdominal ultrasound shows the placenta extending across the internal cervical os. Which diagnosis is most likely?
Show answer and explanation
Answer: A. Placenta previa. Placenta previa presents with painless bright-red bleeding in the second half of pregnancy and is diagnosed by ultrasound showing the placenta covering or near the internal cervical os; digital cervical exam is contraindicated until previa is excluded.
Why the other choices are tempting
- B. Placental abruption presents with PAINFUL bleeding and a tender, rigid uterus, often with concealed bleeding.
- C. Vasa previa causes painless bleeding only after rupture of membranes, with characteristic fetal bradycardia from fetal vessel rupture.
- D. Uterine rupture presents with sudden severe abdominal pain, loss of fetal station, and is typically associated with prior cesarean scar or trauma.
- E. Cervical ectropion can cause light spotting after intercourse but not the brisk bleeding described.
Flashcards
Tap a card to flip it.
What bleeding pattern supports placenta previa?
Painless bright red third-trimester bleeding supports placenta previa.
What bleeding pattern supports placental abruption?
Painful bleeding with uterine tenderness or rigidity supports placental abruption.
Quick answers
What is the fastest way to tell Placenta previa from Placental abruption, vasa previa, and uterine rupture?
Previa: painless bleeding with placenta over the os; abruption: painful tender uterus; vasa previa: ROM with bleeding and fetal bradycardia; rupture: scar pain with fetal distress.
What is the key clue for Placenta previa?
Placenta previa causes painless third-trimester vaginal bleeding with placenta covering or near the cervical os.
What is the key clue for Placental abruption, vasa previa, and uterine rupture?
Abruption causes painful bleeding with uterine tenderness; vasa previa causes painless bleeding with fetal bradycardia after membrane rupture, especially with velamentous cord insertion or succenturiate/bilobed placenta; uterine rupture causes acute pain, fetal distress, and loss of station.
What is the common trap with Placenta previa vs Placental abruption, vasa previa, and uterine rupture?
All can bleed late in pregnancy, so pain, uterine tone, fetal status, membrane rupture, and placental location separate them.