“…The slow onset of action, plus a high incidence of side effects, such as nausea, vomiting, pruritus and the potential for delayed respiratory depression, limit the usefulness of intrathecal morphine for analgesia during labour. Intrathecal injection of a more lipid‐soluble opioid leads to rapid relief of labour pain with fewer side effects, but the duration of analgesia is relatively short [26,27]. Intrathecal fentanyl 25 μg provides a rapid onset of analgesia, but the effect lasts only 60–90 min [28].…”