Trauma to perineal area is one of common problems faced by obstetricians affecting physical, social and mental wellbeing of patients. (Perumal D. et al. 2017) During labor, surgical incision to perineum (episiotomy) is done to facilitate delivery of fetus. (Arulkumaran S. et al 2012) Episiotomy is associated with complication such as hemorrhage, infection, pain and wound breakdown. (Sule ST et al. 2003) Pain relief after episiotomy is primary concern of obstetrician and right of patient. (Brennan F. et al. 2007) Pain after delivery causes delayed mobility of patient, late initiation of breast feeding and may affect mother psychologically.
Suturing of episiotomy is done adhering to basic surgical principles of providing good pain control. (Sultan AH et al. 2014) Traditionally local analgesia using xylocaine is being used during episiotomy and repair. Despite this patients do complain of pain in postpartum period which seems less adequate for patients. One study compared infiltration of bupivacaine and lignocaine for episiotomy and found out that patients with lignocaine had higher pain score at 2, 4, and 6 h after the repair. (Abu-Zaida A. et al. 2021) One meta-analysis also determined that pain was lower with bupivacaine compared to lignocaine after episiotomy. (Fyneface Ogan S et al. 2006) Therefore it is necessary to determine other complementary methods to provide adequate pain relief after episiotomy.
Magnesium sulphate is readily available in obstetric units due to its diverse uses, wide safety margins and cost-effectiveness. Magnesium is a calcium channel blocker and noncompetitive N methyl D aspartate (NMDA) receptor antagonist with anti-nociceptive effects. Blocking of NMDA receptors inhibits central sensitization due to peripheral nociceptive stimulation. (Akhtar MI et al. 2011) Furthermore, there are peripheral NMDA receptors in the muscles, skin, and knee joints that play a role in sensory transmission of noxious signals. The nociceptors release glutamate in response to an afferent signal that binds to NMDA receptors leading to nerve depolarization and heightened sensitivity to circulating neurotransmitters. Magnesium sulphate inhibits these receptors thus producing anti-nociceptive effect. The addition of Magnesium sulphate to local anesthetics for neuraxial anesthesia prolongs the duration of anesthesia and improves the quality of analgesia. (Abd Elsalam KA et al. 2017)
The role of magnesium has been evaluated as adjuvant for intra- and post-operative pain relief in orthopedic, gynecological, and thoracic surgeries and has established role in anesthesia and obstetrics. (Akhtar MI et al. 2011) Moreover studies have determined that subcutaneous infiltration of Magnesium sulphate with local anesthetic after caesarean section prolongs the analgesic efficacy of local anesthetic without any significant adverse effects. (Kundra S et al. 2016) One recent study comparing the effects of using local infiltration of lignocaine only and lignocaine with magnesium after episiotomy sulfate determined that patients have significant pain relief after 2 hours with combination of lignocaine and magnesium sulfate. (Garba JA et al. 2021)
