This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anaesthesia
True statement regarding neuraxial opioids for labor and delivery is 
Select and explain. 
A. Opioids should never be used as a sole agent, B. Most common side effect is fetal bradycardia, C. Intrathecal morphine is associated with quick peak in concentration and early onset maternal respiratory depression, D. Systemic absorption is similar to intramuscular
D: Systemic absorption is similar to intramuscular
Answer: D: Systemic absorption is similar to intramuscular 
Explanation: Most common side effect of  opioids is pruritis. Since epidural space contains extensive vascular plexus systemic absorption is similar to intramuscular injection.