Parenteral opioid analgesia: Does it still have a role?

Parenteral opioids have been used in labour analgesia for many years, but the ideal opioid in this setting is yet to be found. We review the properties of currently used opioids, their analgesic properties and side effects to mother and foetus. Parenteral opioids can be administered as intermittent boluses or through a patient-controlled intravenous administration system. A wide range of opioid drugs are currently used and provide a variable degree of analgesia. All opioids can cause unwanted maternal side effects such as nausea, vomiting, sedation and respiratory depression. They cross the placenta and have the potential to cause neonatal respiratory depression. Remifentanil patient-controlled intravenous analgesia is becoming increasingly available and popular on some delivery suites. It can provide adequate analgesia and is useful when epidural analgesia is contraindicated. Remifentanil patient-controlled analgesia requires close monitoring in an environment familiar with the technique to avoid maternal hypoxia due to respiratory depression.