Examqo › Examqo library › Obstetrics and gynaecology › Obstetrics · IMLE
Placenta praevia, placental abruption and third-trimester bleeding
Painless bleeding with a soft uterus points to placenta praevia; painful bleeding with a hard, tender uterus points to placental abruption; bleeding at membrane rupture with sudden fetal bradycardia points to vasa praevia.
Why it matters in the exam
Vaginal bleeding in the third trimester is one of the classic questions. The clinical story is almost always enough to tell the causes apart: placenta praevia bleeds without pain, and the first bleed is often small and stops by itself; abruption is painful, the uterus is hard as wood, and the fetus is often in distress. The deciding question is usually what must not be done — a digital vaginal examination before praevia is excluded — and what the first step is: ultrasound to locate the placenta.
Candidates are also asked about risk factors and the timing of delivery. For praevia: previous caesarean section, high parity, multiple pregnancy, IVF and smoking. For abruption: hypertension and preeclampsia, smoking, cocaine, abdominal trauma and preterm rupture of membranes. The combination of praevia and a previous caesarean greatly raises the risk of placenta accreta spectrum, which needs a planned delivery in an experienced centre. Severe abruption can cause DIC, and with fetal death and a stable mother vaginal delivery is preferred.
Key points
- Praevia = painless bleeding; abruption = pain and a hard uterus.
- No digital examination before ultrasound.
- Praevia + previous caesarean = suspect placenta accreta.
- Severe abruption can cause DIC; the diagnosis is clinical.
- Vasa praevia: bleeding at membrane rupture with fetal bradycardia → emergency caesarean.
Summary table
| Condition | Clinical picture | Diagnosis | Management and timing of delivery |
|---|---|---|---|
| Placenta praevia | Bright red, painless bleeding, soft uterus; often malpresentation | Ultrasound (transvaginal is safe); repeat scan at 32 weeks | No digital examination; caesarean section at 36 to 37+6 weeks |
| Placenta accreta | Usually no bleeding until delivery; praevia with a previous caesarean | Ultrasound, sometimes MRI | Caesarean with planned hysterectomy at 34 to 35+6 weeks |
| Placental abruption | Pain, hard tender uterus, frequent contractions, fetal distress, shock out of proportion to visible bleeding | Clinical diagnosis; ultrasound misses most cases | Live fetus in distress → urgent caesarean; fetal death and stable mother → vaginal delivery; monitor clotting |
| Vasa praevia | Bleeding at membrane rupture, immediate fetal bradycardia; the blood is fetal | Colour Doppler ultrasound before labour | Planned caesarean at 34 to 37 weeks; if bleeding — emergency caesarean |
| Uterine rupture | Previous caesarean, sharp pain, loss of station of the presenting part, prolonged fetal heart deceleration | Clinical | Immediate laparotomy |
A free exam question
יולדת בשבוע 35 להריונה הראשן, מופנית למיון עקב כאבי בטן ודימום לדני קל בבדיקה : לחץ דם 70/50 ממ"כ דופק 120 לדקה. רחם בטונוס מוגבר. צוואר פתוח ל- 2 ס"מ מחוק 80% , עובר במצג ראש ללא דופק עוברי. כיצד יש להמשיך לנהל את הלידה? (the question as examined, in Hebrew)
- א. ייצוב היולדת וניתוח קיסרי
- ב. מתן אוקסיטוצין וילוד וגינלי
- ג. פקיעת שלפוחית מי שפיר וילוד וגינלי
- ד. הכנסת בלון צווארי ונסיון לילוד וגינלי
In the full version for subscribers
- A simple algorithm
- Memory aid
- Exam traps
- 5 review cards
- Enough for IMLE
The full version is open to subscribers of: Medical licensing exam (IMLE), Obstetrics and gynecology, Emergency medicine, Family medicine, Dermatology and venereology.
Subscriber? Read the full topic Plans and prices 25 free questions
Sources
- ACOG Committee Opinion No. 831, 2021 — Medically Indicated Late-Preterm and Early-Term Deliveries
- ACOG Obstetric Care Consensus No. 7, 2018 — Placenta Accreta Spectrum
- RCOG Green-top Guideline No. 27a, 2018 — Placenta Praevia and Placenta Accreta: Diagnosis and Management
- Williams Obstetrics, 26th edition (2022) — Obstetrical Hemorrhage
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.