When would it be most appropriate for an EMT to prepare for an immediate delivery at the scene?

Preparing for an immediate delivery at the scene is most appropriate when contractions are occurring every 3 minutes and the mother feels the urge to push. This indicates that the labor is progressing rapidly and the baby is likely on the verge of being born. The frequency of the contractions suggests a significant stage of labor, which aligns with the typical timeframe for an imminent delivery.

In this scenario, the mother's urge to push indicates that she is in the second stage of labor, which is characterized by the descent of the baby through the birth canal. This is a critical moment where immediate intervention may be necessary to ensure the safety of both the mother and the newborn. Delaying transportation to a hospital in this situation could pose risks for both, as the baby may be delivered before reaching medical facilities.

In contrast, other scenarios such as irregular contractions or the absence of crowning would not warrant immediate delivery preparation. Contractions that are spaced at 8 to 10 minutes apart typically indicate early labor, and a long distance to the hospital without active labor signs also suggests that there may be time to transport the mother safely before delivery is necessary. While the rupture of membranes is an important factor, it does not, by itself, mean that delivery is imminent unless accompanied by significant labor signs