Which fetal position is most commonly associated with shoulder dystocia?

The occipito-posterior position is most commonly associated with shoulder dystocia due to the mechanics involved during delivery. In this position, the fetal head is facing upward instead of downward, leading to a more challenging angle for the shoulders to navigate through the birth canal. This altered orientation can result in the shoulders getting stuck behind the pubic symphysis, thus increasing the likelihood of shoulder dystocia occurring.

Dystocia refers to a difficult or obstructed labor, and when the baby's shoulders become impacted, it can create a situation that requires urgent intervention to avoid complications for both the mother and the baby. The occipito-posterior position is particularly problematic because of the torque and forces exerted during labor; the shoulders do not align properly for delivery, making shoulder dystocia more likely.

Understanding the biomechanics of different fetal positions is crucial for anticipatory guidance and management options during labor.