Examkin

Question

Difficulty: EasyObstetric Complications

An expectant 34-year-old mother (G3P2) is admitted to the maternity ward at 39 weeks of gestation. She is attempting a vaginal delivery following a previous lower transverse cesarean section. While her labor is progressing, her vital signs show a pulse of 115/min and a blood pressure of 100/60 mm Hg. Suddenly, she cries out, reporting a severe, tearing pain in her lower abdomen. The continuous tocodynamometer, which previously showed regular activity, now indicates a complete cessation of uterine contractions. A rapid bedside pelvic examination reveals that the presenting fetal part, previously palpable at +1 station, has retracted and is no longer easily reached. Simultaneously, the fetal monitor displays a sudden and sustained heart rate deceleration to 80/min. Which of the following is the most likely diagnosis?

  1. A
    Abruptio placentae
  2. B
    Vasa previa
  3. C
    Normal transition phase of labor
  4. Uterine ruptureAnswer
  5. E
    Amniotic fluid embolism

Answer

Uterine rupture
The clinical picture described is the classic presentation of uterine rupture. Key diagnostic features include the sudden onset of severe tearing abdominal pain, the abrupt cessation of uterine contractions, the loss of fetal station (indicating the fetus has extruded through the rupture into the maternal abdomen), and profound fetal distress (bradycardia). The patient's history of a prior cesarean delivery places her at a significantly elevated risk for this catastrophic obstetric emergency during a trial of labor.

Step-by-Step Solution

1
Identify the patient's primary risk factor.
The patient has a history of a previous cesarean delivery.
A scarred uterus is the most significant predisposing risk factor for structural compromise during a trial of labor.
2
Evaluate the acute changes in maternal symptoms and uterine activity.
There is a sudden onset of severe, tearing pain accompanied by a complete cessation of uterine contractions on the tocodynamometer.
These specific signs point to a sudden structural failure of the myometrium, separating it from placental or physiological labor issues.
3
Correlate maternal findings with fetal status.
The presenting fetal part has retracted (loss of station) and the fetus is experiencing profound bradycardia.
When the uterus completely ruptures, the fetus can extrude into the maternal abdomen, causing immediate loss of station and catastrophic fetal hypoxia.

Key Concept

Clinical presentation of uterine rupture during a trial of labor after cesarean delivery.
Rate this question

Topics

Obstetric Complications

More questions from this topic