History of Labor Analgesia

Labor pain has prevailed as long as mankind existed. Many analgesic methods to combat pain during childbirth are found in the writings of ancient Babylonians, Egyptians, Chinese, and Greeks.¹

One of the earliest references on labor analgesia appeared in a gynecologic text written in the first century CE by the Greek physician Soranus of Ephesus. He said that the physician “soothe the pains (by) touching with warm hands and afterwards drench pieces of cloth with warm, sweet olive oil and put them over the abdomen as well as the labia and keep them saturated with the warm oil for some time, and one must also place bladders filled with warm oil alongside.” ² Primitive tribes and Native Americans believed that pain was caused by demons or spirits. These tribal shamans and sorcerers were priests of the spirit and healers of the body. In these cultures, pain was considered a natural process and women have to bear it for a long time. They carried the notion that pain comes as a means to pass a test or as punishment.

Labor pain, in particular, was thought to be a punishment for sexual indulgence during pregnancy. Buddhism viewed pain as a form of punishment for a sin committed in this or a previous life. In 1591, Eufane MacAyane of Edinburgh was dragged from her home, her pleas for mercy was ignored and she was buried alive into a pit because she asked for pain relief during her difficult labor of twin sons.³ The church teachings of that day regarded the pain of childbirth as a punishment justly inflicted by God to women and asking for relief from pain was presumably against God's wishes and Eufane was punished for that sin.⁴ The woman in labor, accompanied by a female relative or friend would leave the village to some retired spot; upon the banks of a stream was the favorite spot the world over. The vicinity of water, moving water if possible, was sought, so that the young mother could bathe herself and her child and return to the village cleansed and purified when all was over. But while the labor of the primitive woman was usually easy and relatively painless, in the presence of some pathological condition, her agonies often ended in death.⁵

Simpson said: “In the trials of the 16^th century we find many cases in which witches were prosecuted for attempting to abolish the pains of labor by charms and other means. One method that was practiced was to hold a sword before the patient, who was directed to look at it steadily, in the same way that Latona is said to have held a palm branch, and brought forth Apollo without suffering; an attempt at mesmerism in reality. Another way employed was to hang the husband up in the next room by his feet till the labor was accomplished.⁸ In Egypt, ancient Petroglyphs (rock carvings) are rumored to depict the waterbirths of pharaohs some 8,000 years ago. Similarly from as early as 2700 BC, the Minoan civilization on the island of Crete created temples in which women labored and birthed in water.⁹ The first recorded account of a waterbirth in the modern Western world occurred in a village in France in 1803. After laboring for some 48 hours a woman was helped into a warm bath by her doctor in an effort to soothe her and provide temporary pain relief. Shortly after entering the bath the woman's stalled labor quickly progressed, and her baby was born before any effort could be made to remove her form the bath.

The Renaissance was a time of greater tolerance and permitted the use of medications forgotten during the Middle Ages. Hashish was employed as anesthesia in ancient China and opium was used in Greece as a means “to forget one's sorrows”.4

In the Middle Ages, various herbal concoctions based on extract of poppy, Mandragora, henbane, and hemp were introduced. The use of white willow bark (a predecessor of acetylsalicylic acid) has also been documented to relieve labor pain.

Nonpharmacological method of pain relief like transcutaneous electrical nerve stimulation (TENS) and Hein's method were cumbersome and made delivering mother difficult to nurse (Figures 5 and 6). The Hein's apparatus was an apparatus produces negative pressure around the abdomen to make the uterus spherical during contraction so it could reduce the pain of labor. In 1844, English Mesmerist JP Lynell provided a week of mesmerism culminating in painless delivery. “I have the idea of magnetizing a pregnant woman before delivery. Imagine such a discovery as birth without pain! He had said.” ¹¹ William Fahnestock (Lancaster, Pennsylvania) practiced “somnambulism” and “mesmerism”, producing a “stuporous trance”.5

He reported two deliveries managed without pain. Susan Herr had lost her eyesight and use of her legs with a previous painful delivery. Sight, mobility, and painless labor were all obtained with “somnambulistic trance” during her next delivery.¹²

In the 18^th century, the advent of modern anesthesia and pharmacology marked a turning point in the treatment of pain. In January, 1847, barely 3 months after WTG Morton demonstrated ether anesthesia, James Y Simpson of Edinburgh first used ether to produce analgesia in midwifery (Figure 7).

Simpson was able to prove by the Bible that God had promised on several occasions to remove the curse. Simpson argued persuasively that “sorrow” was improperly translated. It was more properly “labor”, “toil”, or “physical exertion”. He argued that God had permitted Adam to sleep when the rib was harvested to create women. Thus, clearly anesthesia was divinely acceptable. Furthermore, he argued that if: “we were to admit that woman was as a result of the primal curse, adjudged to the miseries of pure physical pain and agony in parturition, still, certainly under the Christian dispensation, the moral necessity of undergoing such anguish has ceased and terminated.”^8,13 In March 1847, Flourens, announced the anesthetic properties of chloroform. Simpson, in November, read his paper entitled, “Notice of a New Anesthetic Agent as a substitute for Sulfuric Ether in Surgery and Midwifery.” From this time onwards, there was a rapid development of chloroform anesthesia, while after the death of Wells little use was made of nitrous oxide until after Edmund Andrews, in 1868, suggested its use with oxygen.7

Ten years later, Paul Bert conducted exhaustive experiments to show the safety of nitrous oxide and oxygen as an anesthetic. The first woman anesthetized for childbirth in the United States was Fanny Longfellow in 1847 for her third child (Figure 9). She was the wife of the American poet HW Longfellow, who actually administered ether. She later wrote the following: “I did it for the good of women everywhere as no woman should have to suffer that much pain. I am very sorry you all thought me so rash and naughty in trying the ether. Henry's faith gave me courage and I had heard such a thing had succeeded in abroad where the surgeons extend this great blessing more boldly and universally than our timid doctors…. This is certainly the greatest blessing of this age.” The second woman who was to become famous was Emma Darwin, the wife of Charles Darwin the eminent 19 ^th century Naturalist. Emma had chloroform given to her by her husband for the last two of her eight births. The first time she used chloroform was in 1847 which was before Queen Victoria (1853). This left an indelible impression upon her so much so that for her last birth she was screaming “Get me the chloroform”. In 1853, Queen Victoria, undaunted by the clergy and with the strong encouragement of her husband Prince Albert, convinced her reluctant physicians, to have chloroform administered to her by John Snow (Figure 10) for her eighth confinement of Prince Leopold. Snow wrote afterwards, “her Majesty expressed great relief from the application, the pains being trifling during the uterine contractions, and whilst between the periods of contraction there was complete ease.” Queen Victoria's endorsement of chloroform subsequently popularized its use. Snow administered the chloroform again for her ninth and last confinement of her daughter Princess Beatrice. Later, the Archbishop of Canterbury's (leader of the Anglican/Episcopal Church) daughter in 1855 receives chloroform for labor pains.8

He refused to criticize her. The 18 ^th and 19 ^th century witnessed ether and morphine fight labor pain. They realized that the diminished uterine contractions and depressed child constituted an unacceptable risk for normal labor. Later, in 1847, physicians used the same arguments against the use of ether or chloroform to treat the pain of childbirth. ¹⁴ Klikowitsch of Petrograd applied nitrous oxide-oxygen analgesia to twenty-five obstetrical cases in 1880s. He used 80% nitrous oxide and 20% oxygen, and observed that three or four inhalations rendered the uterine contractions painless without clouding the consciousness. The following year, Winckel of Dresden used the nitrous oxide-oxygen analgesia in 50 cases. In speaking of the clinical results Winckel said: “The pulse of the parturient woman is usually slowed considerably by laughing gas, but finally reaches its original rate again. The child's pulse is also slower in 8%, but usually it seems to be more frequent. The woman's temperature rises often several tenths of a degree. At first the pupils are somewhat contracted. The pains are not the same in strength or duration, but are often more frequent and stronger, and existing vomiting frequently ceases. Klikowitschand and I have both observed aphasia, and once in 50 cases a hysteroepileptic attack was caused, and in one a real epileptic seizure followed its use, but otherwise no bad effects were observed, either as regards the mother or the child. The oxygen of the blood remains in normal combination, while the nitrous oxide probably circulates in much looser chemical combination in the blood, absorbed by the plasma. These researches should be supplemented by the observations of others, and were by no means thought conclusive by us, as Doederlein believes. It seems to me most practical to get the mixture from the apothecary, as was formerly the case, and that he should be provided with rubber bags, which he may fill and furnish the physician when needed. In this manner the gas might be introduced into private practice and would not be monopolized by the clinics.9

Hypnosis was tried successfully in few patients but was unsatisfactory in a large number of patients.¹⁷ Dick-Read, the spiritual father of natural childbirth, believed that childbirth revealed God's presence in the universe: it was the task of science to render it explicit, by showing the laws of nature that governed the processes of birth. He rejected the need for pain relieving drugs during childbirth. He said that pain was principally a product of preconceived fear and tension (he called it the “fear-10tension-pain” syndrome). He believed that women who were properly prepared could control labor pain themselves—without having to resort to medication. In order to achieve this, he stressed the importance of education, exercise, and relaxation. He developed a theory of childbirth that sought to integrate body and mind, individual, and culture in 1933.^18,19 According to Dick-Read, these psychological techniques would not only eliminate pain, but also shorten labor and reduce the need for surgical interference. Natural childbirth, however, was already losing ground to the “psychoprophylactic” technique advocated by the French obstetrician Ferdinand Lamaze. In 1958 the Natural Childbirth Association itself shifted its allegiance to Lamaze.²⁰ The psychoprophylactic method of Lamaze was the most popular form of psychological anesthesia. This technique relied on patient education and positive conditioning to decrease fear of giving birth. The patient is asked to focus and concentrate on an object or a location away from herself, maintain a breathing rhythm, listen to reassuring words which relieved the muscle tension and decreased her pain associated with uterine contractions. However, this method was effective only in early labor.^21,22 Leboyer described his method as “Birth without violence” in 1977.²³

Morphine was isolated from crude opium by Serturner in 1806. Alexander Wood of Edinburgh invented the hypodermic syringe and hollow needle in 1853. Steinbuchael of Graz was the first to use morphine with scopolamine injection in 1902 to produce “twilight sleep”. This method of pain relief was used extensively for the next 30 years until the drawbacks of maternal restlessness, protraction of labor and neonatal respiratory depression were known. Pethidine was synthesized in Germany in 1939 and used first for labor analgesia in 1940s. Since 1951, midwives were allowed to prescribe and use pethidine for domiciliary practice. Pentazocine was also widely used around this time. Levollorphan (1950) and Nalorphine (1952) reduced the hazards of narcotic analgesics for mother and the neonate. Very low doses of Ketamine ²⁵ was used in early 1970s with no hallucinations in the mother or side effects in the fetus. The early 1980s witnessed the use of fentanyl in obstetrics. Fentanyl 11was popular for intrathecal administration or continuous/intermittent epidural administration combined with a dilute solution of local anesthetic in laboring patients and walking epidural was a reality. Thus the golden era of labor analgesia started. Alfentanil and sufentanil were approved for use after 1996. Sufentanil was used epidurally as well as through the intravenous route with great success. ²⁶ Remifentanil, a µ-opioid receptor agonist, was approved for clinical use in United States since 1996. This ultrashort-acting drug with an estimated half-life of 1.3 minutes, absence of maternal and fetal accumulation, intense analgesia, rapid metabolism, and redistribution provided an attractive alternative systemic analgesic in parturients in whom regional anesthesia was contraindicated.

Koller used cocaine in the cornea in 1884. In the year that followed, Halstead from Baltimore performed nerve blocks onto himself. In 1910, Stiasny applied cocaine topically to the vagina and vulva to relieve pain of labor. Gellhom, in 1927, described the infiltration of the perineum with local anesthetic solutions.¹ The introduction of neuraxial analgesia into obstetric practice took place at the end of 19^th century, 1 year after August Bier, a German surgeon, described six lower extremity operations rendered painless by means of “cocainization of the spinal cord”. Oscar Kreis, a Swiss obstetrician, described total anesthesia of the lower body in six laboring parturient after subarachnoid injection of cocaine. He injected 0.01 g of cocaine intrathecally at L 4-5 interspace and observed complete pain relief within 5–10 minutes. Like Bier, Kreis observed no serious complications, but severe vomiting and headache occurred frequently. Postdural puncture headache (PDPH) would prove to be one of the main limitations associated with subarachnoid block for labor analgesia.²⁷

It was not until 1960s and 1970s that regional/epidural analgesia became widely available. Prior to that, anesthesia services dedicated to the provision of epidural analgesia did not exist. Varying concentrations of lignocaine initially and bupivacaine was used. The discovery of opioid receptors in the spinal cord led to the use of opioid/local anesthetic mixtures that further reduced maternal motor block and risk of local toxicity. Fentanyl and sufentanil are the popular opiates used even today.²⁸

Advances in the field of labor analgesia have walked a long journey from the days of ether and chloroform in 1847 to the present day practice of comprehensive labor pain management using evidence-based medicine.²⁹ The understanding and utilization of obstetric analgesia has hence been accomplished to a remarkable extent. The application of safer agents and techniques, advances in scientific knowledge and a change in the attitude of everybody concerned with labor analgesia has revolutionized labor analgesia practice.