Final answer:
Monitoring the fetal heart rate is the highest priority nursing action following a spontaneous amniotomy to ensure the baby's well-being and to identify any signs of distress.
Step-by-step explanation:
The highest priority nursing action when a laboring patient experiences a spontaneous amniotomy is to monitor fetal heart rate. This is critical as it can provide immediate information about the baby's wellbeing and can indicate potential distress. A baseline fetal heart rate should be established and continued monitoring helps to ensure that any signs of distress are identified and managed as quickly as possible. Other assessments, such as checking maternal blood pressure and assessing cervical dilation, are also important but do not take precedence over monitoring the fetal heart rate.