Final answer:
Oligohydramnios in maternal history is a risk factor for umbilical cord prolapse during childbirth, as it can increase the chances of umbilical cord compression and prolapse due to the lack of adequate amniotic fluid cushioning.
Step-by-step explanation:
The factor in maternal history that should alert the nurse to the potential for a prolapsed umbilical cord is a. Oligohydramnios. Oligohydramnios refers to a condition in which there is too little amniotic fluid surrounding the baby. This can be problematic because amniotic fluid serves as a cushion for the baby, and too little of it increases the risk of umbilical cord compression, which can lead to cord prolapse, a situation where the umbilical cord drops through the open cervix into the vagina ahead of the baby. This is an urgent situation requiring medical intervention as it can compromise the baby's oxygen supply.
Pregnancy at 38 weeks (b), the presenting part at station -3 (c), and meconium-stained amniotic fluid (d) are other conditions which are not directly associated with a higher risk of cord prolapse when compared to oligohydramnios. Though meconium-stained amniotic fluid indicates fetal distress, it does not increase the likelihood of a prolapsed cord as much as oligohydramnios does.