What sign indicates to the nurse that the placenta has separated after a precipitate delivery?

The change in uterine shape is an important and observable sign indicating that the placenta has separated after a precipitate delivery. When the placenta detaches from the uterine wall, the shape of the uterus transitions as it contracts and expels the placenta. This can often be seen as the uterus becomes firmer and may retract upward, altering its previously rounded appearance.

In the context of a precipitate delivery, where labor is exceptionally quick, monitoring these changes is crucial for the nurse. A change in uterine shape not only signifies placental separation but also helps in assessing the overall progression of the third stage of labor.

Increase in fetal heart rate is not a direct indicator of placental separation, as it often reflects fetal response to labor or stress rather than the status of the placenta. Similarly, a decrease in blood pressure does not specifically indicate placental separation and may be unrelated to uterine changes. Feeling fullness in the abdomen can occur for various reasons, including retained products or an unretracted uterus, but it does not specifically signal the separation of the placenta. Therefore, a change in uterine shape remains the most reliable sign of this critical event.