Background: Episiotomy was a surgical procedure at external genitalia for widening of the vaginal outlet during labor. It is known to cause postpartum perineal pain and may have effects on quality of life.
Objective: The present study aimed to compare the analgesic effect of dexamethasone with lidocaine and lidocaine infiltration alone during episiotomy. The primary and secondary outcomes were the analgesic efficacy and postpartum analgesic rescue, respectively.
Materials and Methods: Three hundred and sixty healthy singletons parturient who spontaneously delivered at Thammasat University Hospital were recruited. Participants were randomly assigned into two groups using systemic random sampling. Local infiltration of dexamethasone (4 mg) with lidocaine hydrochloride (100 mg) and lidocaine hydrochloride alone was performed in study and control group, respectively. Pain score was assessed by numerical rating scale and recorded immediately after delivery and after perineal repair, then again at 2-, 6- and 24-hours postpartum. The primary outcome was analgesic efficacy represented by postpartum pain scores. The amount of postpartum acetaminophen consumption and postpartum complications were evaluated for secondary outcome.
Results: Both study and control group had comparable demographic and clinical characters. Pain score by numerical rating scale (NRS) of the study group was statistical lower than the control group at immediate after episiotomy wound repairing and 2 hours postpartum. Both groups had equal pain intensity until 24 hours postpartum. Analgesic rescue during the first 24 hours after delivery in the study group was lower than the control group (p = 0.025). There was no report of wound infection and serious side effect.
Conclusion: Local infiltration of dexamethasone plus lidocaine before performing episiotomy gave a significant pain relief immediately after perineal repair, 2 hours postpartum and decreased analgesic rescue requirement.

Keywords: Dexamethasone, Lidocaine, Episiotomy, Pain