150 years in pursuit of optimal pain relief during labour.

Abstract

Pharmacological relief of pain during childbirth has been both praised and vilified by the public and by physicians. When Simpson first described anaesthetising a woman for childbirth in 1847, strong criticism followed from the medical community and the public. Was it safe? Was it wise to intervene in a natural process? Would it affect the course of labour or the neonate? Simpson contended that pain is without physiological value and only degrades and destroys those who experience it (Caton The history of obstetric anesthesia, in Chestnut's Obstetric Anesthesia. Amsterdam: Elsevier 2014:3–12). By 1860, public opinion changed and women began requesting pain relief from their obstetricians. Pain during childbirth lost its theological connotation and became a biological process to be studied scientifically. Technology was developed that allowed administration of parenteral medications, and ‘twilight sleep’, a popular combination of morphine analgesia and scopolamine for amnesia, was introduced in 1902. Reports of newborn depression soon followed, suggesting placental transmission of the anaesthetic agents. These concerns led to studies of placental structure and appropriate maternal dosing. In the early twentieth century, spinal anaesthesia using cocaine was described for labour analgesia, but women often developed what was probably hypotensive shock with fetal bradycardia. The technique was not well accepted. Obstetric leaders of the day opined that spinal anaesthesia was unlikely to be successfully adopted for obstetric practice and certainly not in preference to general anaesthesia (Lea. J Obstet Gynaecol Br Emp 1902;1:71–88). A review by Sturrock entitled The Relief of Pain in Labour stated that ‘provided the technique of administration is mastered and the risks are recognized, there is little doubt that [twilight sleep] is safe and efficient,’ but insisted that ‘spinal anesthesia is contraindicated during pregnancy and labour,’ (Sturrock. J Obstet Gynaecol Br Emp 1939;46:426–42). Just as regional anaesthesia techniques for labour were becoming commonplace in the 1970s, the ‘natural childbirth’ movement appeared, arguing that women could ‘avoid labour pain if they learned to abolish their fears’. Anaesthesia for labour again fell out of favour. Modern obstetric anaesthesia practice presents options to the pregnant woman, allowing her individualise her labour experience. Fleet et al. offer yet another option for labouring women (BJOG 2015;122:984–993) Fentanyl, a short-acting opioid without active metabolites, was given by intranasal or subcutaneous routes and compared with intramuscular pethidine. Women receiving fentanyl were more satisfied and had less sedation and nausea. Their neonates had fewer nursery admissions and less difficulty establishing breastfeeding. No intravenous line is necessary, and the intranasal route is patient-controlled and does not require painful injections. A statement from the American Society of Anesthesiologists and the American College of Obstetricians and Gynecologists states: ‘Labor causes severe pain for many women. There is no other circumstance where it is considered acceptable for an individual to experience untreated severe pain, amenable to safe intervention, while under a physician's care…maternal request is a sufficient medical indication for pain relief during labor,’ (AGOG No 259. Obstet Gynecol 2004;104:213). Options for pain relief continue to expand. None declared. Completed disclosure of interests form available to view online as supporting information.