The rates of PDPH following unintentional dural puncture with placement of an intrathecal catheter will be compared in two groups: intrathecal morphine (treatment) versus intrathecal saline (control) administered 1-2 hours after delivery, followed by immediate catheter removal. Patients randomized to the treatment group (morphine) will receive preservative-free morphine 0.3 mL (150 mcg) intrathecally. Those randomized to the control group will receive normal saline 0.3 mL intrathecally. After administration of intrathecal morphine, all patients will have their respirations monitored every hour for a period of 12 hours and then every two hours for a period of 12 hours. On postpartum days 1-5, all patients will be visited daily while inpatient and/or contacted by phone after discharge from the hospital.