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Obstetric anesthesia or obstetric anesthesiology, also known as ob-gyn anesthesia or ob-gyn anesthesiology, is a sub-specialty of
anesthesiology Anesthesiology, anaesthesiology, or anaesthesia is the medical specialty concerned with the total perioperative care of patients before, during and after surgery. It encompasses anesthesia, intensive care medicine, critical emergency medicine, ...
that provides peripartum (time directly preceding, during or following childbirth) pain relief (
analgesia Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professionals ...
) for labor and
anesthesia Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), ...
(suppress consciousness) for cesarean deliveries ('C-sections'). Other subspecialty options for anesthesiology include cardiac anesthesiology, pediatric anesthesiology, pain medicine, critical care, neuroanesthesia, regional anesthesia, transplant anesthesia and trauma anesthesia.


Scope

Obstetric anesthesiologists typically serve as consultants to ob-gyn physicians and provide pain management for both complicated and uncomplicated pregnancies. An obstetric anesthesiologist's practice may consist largely of managing pain during vaginal deliveries and administering anesthesia for cesarean sections; however, the scope is expanding to involve anesthesia for both maternal as well as fetal procedures. Maternal-specific procedures include cerclage, external cephalic version (ECV), postpartum bilateral
tubal ligation Tubal ligation (commonly known as having one's "tubes tied") is a surgical procedure for female sterilization in which the fallopian tubes are permanently blocked, clipped or removed. This prevents the fertilization of eggs by sperm and thus th ...
(BTL), and
dilation and evacuation Dilation and evacuation (D&E) is the dilation of the cervix and surgical evacuation of the uterus (potentially including the fetus, placenta and other tissue) after the first trimester of pregnancy. It is a method of abortion as well as a common ...
(D and E). Fetus-specific procedures include fetoscopic laser photocoagulation and ex-utero intrapartum treatment (EXIT). However, the majority of care given by anesthesiologists on most labor and delivery units is management of labor analgesia and anesthesia for cesarean section.


History

The administration of general anesthesia in operative procedures was publicly demonstrated by
William Thomas Green Morton William Thomas Green Morton (August 9, 1819 – July 15, 1868) was an American dentist and physician who first publicly demonstrated the use of inhaled ether as a surgical anesthetic in 1846. The promotion of his questionable claim to have been th ...
(1819–1868) in Boston, October 1846 as the first successful practice of its kind. This practice revealed the pain-annulling properties of ether inhalation during surgery. Pioneers of obstetric anesthesia extended these findings to cases of parturition or childbirth, notably including
James Young Simpson Sir James Young Simpson, 1st Baronet, (7 June 1811 – 6 May 1870) was a Scottish obstetrician and a significant figure in the history of medicine. He was the first physician to demonstrate the anaesthetic properties of chloroform on humans ...
of Scotland (1811–1870),
John Snow John Snow (15 March 1813 – 16 June 1858) was an English physician and a leader in the development of anaesthesia and medical hygiene. He is considered one of the founders of modern epidemiology, in part because of his work in tracing the so ...
of London (1813–1858) and Walter Channing of the United States (1786–1876). Prior to the anesthetizing of
Queen Victoria Victoria (Alexandrina Victoria; 24 May 1819 – 22 January 1901) was Queen of the United Kingdom of Great Britain and Ireland from 20 June 1837 until Death and state funeral of Queen Victoria, her death in 1901. Her reign of 63 years and 21 ...
in 1853, the use of diethyl ether and chloroform as obstetric anesthetics faced social, religious, and medical opposition. With the shift in social attitudes, women became less reserved towards this novel practice and began coercing physicians to administer powerful anesthetics during labor. Medical objections were similarly disintegrated with casebook publications that reflected the safety of obstetric anesthesia for both mother and child. Thus the advent of obstetric anesthesia facilitated the use of instruments during delivery as obstetricians were afforded greater scope in terms of these materials. Following Morton's use of ether as an anesthetic, James Simpson conducted his own obstetric anesthetic trial on January 19, 1847 using an open-drop approach to administer ether. However, due to its post-analgesic effect of nausea and vomiting, he later switched to using chloroform instead. Simpson's later personal discovery of chloroform's anesthetic properties inspired subsequent trials with chloroform that he went on to make public in November 1847. The Medico Surgical Society publication of Simpson's findings was not well received and required significant defense thereafter. Three months later, on April 7, 1847, ether was used for the first time in American obstetrics. Following that initial administration documented in the Boston Medical and Surgical Journal by N.C Keep, Walter Channing described several obstetric cases in which he successfully employed sulfuric ether in the United States. John Snow was responsible for anesthetizing the Queen and is also attributed for influencing public and medical opinions on obstetric anesthesia through his various recorded experiences Though the birth of the Queen's 8th child Prince Leopold on April 7, 1853, was not generally publicized, the London social elite were aware of the use of chloroform in this delivery and found it appealing. Until this time, there had been considerable public and religious opposition to obstetric anesthesia. A woman, Eufame MacAlayne, was buried alive in Scotland in 1591 just for ''seeking'' pain relief for the birth of her two sons. This societal aspect of childbirth was recognized by Dr. Churchill of Dublin and later published on the statistics of obstetric anesthesia. Churchill suggested wealthier individuals were recorded to have easier births from the use of such drugs. In the practice of obstetric anesthesia, John Snow greatly differed from Simpson in that Snow emphasized proper quantity measurements and the delay of administration until the second stage of labor commenced. Snow additionally disagreed with Simpson's argument that the laboring patient should be anesthetized to the level of unconsciousness. These differences among others are why the title "Father of Obstetric Anesthesia" has become so controversial.


Religious opposition

Labor analgesia was debated on the grounds of religion and morality, which John Simpson used as his own weapon against opposition. Biblical literalism led many to interpret labor pains as punishment for sin and deemed obstetric anesthesia impious with respect to the primeval curse. Simpson advocated that “whosoever shall keep the whole law and yet offend in one point, is guilty of all”. In this sentiment he is referring to many of the medical practitioners who mitigate minor pains but avoid obstetric anesthetics for fear of opposition or religious persecution. Critic Charles Meigs exemplified this belief of the physiological value in parturition pain, which the greater public supported throughout the mid 19th century. The natural benefits of such labor pains which initially inhibited the practice of obstetrical analgesia, originated from another religious consideration of perfection. Religious opponents argued that individuals of God’s creation and His standard of perfection should not be in need of such obstetrical interference. Natural processes employed by the Almighty Himself should be left untouched. In support of this claim, M. Roussel advocated that the refinement of society through technical operations (i.e. anesthesia) causes more harm then good to the natural process of childbirth.


Medical objections

Medical historian Richard Shyrock suggested that humanitarian sentiments motivated 19th century physicians, while science shaped their practice. Victorian practitioners believed that if suffering was preventable it was their duty to abolish it in any way possible. Though physicians responsible for administering anesthesia were known to evade interfering in delivery if the mother was an uncivilized member of society. These individuals were left to their own resources, perhaps benefiting from midwife assistance. The pathological process of childbirth was seen to be of necessity for successful delivery and dulling the pain of contractions would hinder this process, until Simpson was able to overturn this theory in 1854. The inhalation of anesthetic agents do not affect the act of labor or the mechanism by which uterine contractions occur, but rather renders the woman insensible to the high degree of pain. With this finding, along with the statistical records of safely executed anesthetic administrations, the medical opposition to obstetric analgesia for pain annulment was suppressed. The conflicting clinical interpretation of obstetric labor as natural pain, as opposed to discomfort induced by an abnormal or diseased condition, led obstetric practitioners and midwives alike to endorse laissez-faire treatment. Natural, animalistic functions of child rearing were determined thereafter not to require the assistance of obstetricians or subsequent labor analgesia. Following an era of natural philosophy, physicians evoked the ability of wild animals and ‘savaged individuals’ to deliver offspring in regions where the practice of child rearing had never been reduced to an art form. The likening of any obstetrical practice to mere pretend science, including the delivery of anesthetic agents, further prolonged the advancement of this field considerably throughout the 19th century.


Social implications

The social distinction of labor analgesia practice strengthened the divide between savaged and civilized society, while highlighting gender roles in medical practice. The results of unassisted labor in uncivilized communities, specifically the vitality of both mom and fetus, were not documented well. The news of this ‘anti-obstetric’ practice failed to spread to the civilized community, allowing the means of obstetric interference through general and anesthetic intervention to persist. Documentation and statistical evidence was favored throughout the development of obstetric anesthesia to determine the viability of physician strategies. The obstetric diary of midwife
Martha Ballard Martha Moore Ballard (February 9, 1735 – June 9, 1812) was an American midwife and healer. Unusually for the time, Ballard kept a diary with thousands of entries over nearly three decades, which has provided historians with invaluable insi ...
(1735–1812) is historically valued for she documented the details of all midwife calls, as well as physician assistance, instrument usage, and symptoms. Being one of the first women to provide a history of obstetrical practice, Martha Ballard’s notes regarding the marginalization of women in medical practice and the arrogance of male physicians were taken into careful consideration.


Morphine

The isolation of morphine in the early 1800s was yet another milestone in obstetric anesthesia. However, the drug would not be widely used until the invention of the hypodermic needle in the 1850s. The first to use a hypodermic syringe in the United States was Fordyce Barker, who actually received the syringe from H.J Simpson as a gift during a visit to Edinburgh. Eventually, the use of morphine for pain control during labor lost favor due to its effects of respiratory depression in the newborn and was replaced largely by meperidine, a synthetic narcotic, first made in Germany in 1939, that had less of an effect on respiratory depression. Meperidine is still popular in obstetrics today.


Local anesthetics

Probably the most important discovery in obstetric anesthesia was the introduction of
regional anesthesia Local anesthesia is any technique to induce the absence of sensation in a specific part of the body, generally for the aim of inducing local analgesia, that is, local insensitivity to pain, although other local senses may be affected as well. It ...
, in which local anesthetics are used to block pain from a large area (or nerve distribution). Cocaine, the first local anesthetic was used topically in ophthalmology in 1884 by Carl Koller. William Halstead completed the first
nerve block Nerve block or regional nerve blockade is any deliberate interruption of signals traveling along a nerve, often for the purpose of pain relief. Local anesthetic nerve block (sometimes referred to as simply "nerve block") is a short-term block, u ...
; August Bier, the first clinical
spinal anesthesia Spinal anaesthesia (or spinal anesthesia), also called spinal block, subarachnoid block, intradural block and intrathecal block, is a form of neuraxial regional anaesthesia involving the injection of a local anaesthetic or opioid into the subarac ...
; Sicard and Cathlein, the caudal approach to epidural anesthesia in 1901; and Fidel Pages, the lumbar epidural approach in 1921. In 1921, the first vaginal delivery under spinal analgesia was reported by Kreiss in Germany. George Pitkin is credited with popularizing obstetric spinal anesthesia in the United States. Charles B. Odom introduced lumbar epidural analgesia to obstetrics in 1935.


Investigations

The anesthesiologist relies on several patient monitors intraoperatively to safely care for the patient. These include, but are not limited to,
pulse oximetry Pulse oximetry is a noninvasive method for monitoring a person's oxygen saturation. Peripheral oxygen saturation (SpO2) readings are typically within 2% accuracy (within 4% accuracy in 95% of cases) of the more accurate (and invasive) reading of ...
,
capnography Capnography is the monitoring of the concentration or partial pressure of carbon dioxide () in the respiratory gases. Its main development has been as a monitoring tool for use during anesthesia and intensive care. It is usually presented as a g ...
, electrocardiogram, non-invasive blood pressure cuff monitoring and temperature. In some cases, arterial blood gas monitoring may be used.


Treatments

Anesthesia for labor and vaginal delivery includes various modalities including pharmacological and non-pharmacological techniques.


Non-pharmacological

Non-pharmacological techniques include
Lamaze The Lamaze technique, also known as the psychoprophylactic method or simply Lamaze, began as a prepared childbirth technique. As an alternative to medical intervention during childbirth, it was popularized in the 1950s by French obstetrician Dr. ...
breathing,
acupuncture Acupuncture is a form of alternative medicine and a component of traditional Chinese medicine (TCM) in which thin needles are inserted into the body. Acupuncture is a pseudoscience; the theories and practices of TCM are not based on scientifi ...
,
acupressure Acupressure is an alternative medicine technique often used in conjunction with acupuncture or reflexology. It is based on the concept of life energy, which flows through "meridians" in the body. In treatment, physical pressure is applied to ac ...
, LeBoyer technique, transcutaneous nerve stimulation, massage, hydrotherapy, vertical positioning, presence of a support person, intradermal water injections, and biofeedback amongst many more. Water immersion in the first stage of labor may reduce women's use of epidural. A meta analysis showed there may be benefits to the presence of a support individual (doula, family member) including lower use of pharmacologic analgesia, decreased length of labor, and lower incidence of cesarian section. Hypnosis warrants further investigation.


Medications

Obstetric anesthesiologists employ the following pharmacological agents and techniques: * Parenteral (IV) agents:
opioid Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid us ...
s such as
meperidine Pethidine, also known as meperidine and sold under the brand name Demerol among others, is a synthetic opioid analgesic, pain medication of the phenylpiperidine class. Synthesized in 1938 as a potential anticholinergic agent by the German chemis ...
,
morphine Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies (''Papaver somniferum''). It is mainly used as a analgesic, pain medication, and is also commonly used recreational drug, recreationally, or to make ...
(rarely used today), and
fentanyl Fentanyl, also spelled fentanil, is a very potent synthetic opioid used as a pain medication. Together with other drugs, fentanyl is used for anesthesia. It is also used illicitly as a recreational drug, sometimes mixed with heroin, cocaine ...
* Inhalation agents: volatile anesthetics such as
isoflurane Isoflurane, sold under the brand name Forane among others, is a general anesthetic. It can be used to start or maintain anesthesia; however, other medications are often used to start anesthesia rather than isoflurane, due to airway irritation w ...
,
sevoflurane Sevoflurane, sold under the brand name Sevorane, among others, is a sweet-smelling, nonflammable, highly fluorinated methyl isopropyl ether used as an inhalational anaesthetic for induction and maintenance of general anesthesia. After desflura ...
, and
desflurane Desflurane (1,2,2,2-tetrafluoroethyl difluoromethyl ether) is a highly fluorinated methyl ethyl ether used for maintenance of general anesthesia. Like halothane, enflurane, and isoflurane, it is a racemic mixture of (''R'') and (''S'') optical i ...
or nitrous oxide. * Neuraxial (regional) anesthetic and analgesia techniques: (e.g. epidural, spinal, combined spinal-epidural) are used most widely in the United States today. These regional techniques are considered the most effective form of labor pain relief (vaginal deliveries) with high rates of maternal satisfaction. Other nerve blocks for labor include paracervical and pudendal blocks which target different nerve distributions. Anesthesia for cesarean sections (C-sections) most commonly uses neuraxial (regional) anesthesia due to its better safety profile for both mother and baby. However, for emergencies or cases where neuraxial anasthesia cannot be used, general anesthesia is used instead. Drugs used to induce general anesthesia include
thiopental Sodium thiopental, also known as Sodium Pentothal (a trademark of Abbott Laboratories), thiopental, thiopentone, or Trapanal (also a trademark), is a rapid-onset short-acting barbiturate general anesthetic. It is the thiobarbiturate analog of pe ...
,
propofol Propofol, marketed as Diprivan, among other names, is a short-acting medication that results in a decreased level of consciousness and a lack of memory for events. Its uses include the starting and maintenance of general anesthesia, sedation f ...
,
etomidate Etomidate (USAN, INN, BAN; marketed as Amidate) is a short-acting intravenous anaesthetic agent used for the induction of general anaesthesia and sedation for short procedures such as reduction of dislocated joints, tracheal intubation, cardiove ...
, and
ketamine Ketamine is a dissociative anesthetic used medically for induction and maintenance of anesthesia. It is also used as a recreational drug. It is one of the safest anesthetics, as, in contrast with opiates, ether, and propofol, it suppresses ne ...
. Unconsciousness is maintained using inhalation agents, and muscle relaxing agents are used as needed. Opioids are less commonly used prior to delivery due to fear of adverse effects on the neonate. However under certain circumstances it is important to attenuate the hypertensive responses to induction and incision and ultra-short acting opioids (remifentanil and alfentanil) appear to be efficacious and safe.


Training


United States

In the United States, obstetric anesthesiology is a sub-specialty of anesthesiology (i.e., an anesthesiologist trains for an additional year as a fellow to qualify as an obstetric anesthesiologist). After earning a four-year undergraduate bachelor's degree, students enroll in a four-year graduate education leading to a degree in medicine (the
Doctor of Medicine Doctor of Medicine (abbreviated M.D., from the Latin language, Latin ''Medicinae Doctor'') is a medical degree, the meaning of which varies between different jurisdictions. In the United States, and some other countries, the M.D. denotes a profes ...
degree (M.D.)) or in osteopathic medicine (the
Doctor of Osteopathic Medicine Doctor of Osteopathic Medicine (DO or D.O., or in Australia DO USA) is a medical degree conferred by the 38 osteopathic medical schools in the United States. DO and Doctor of Medicine (MD) degrees are equivalent: a DO graduate may become licens ...
degree (D.O.)). After receiving a medical degree, students must complete a four-year residency training at an approved anesthesiology program and pass certification exams to become a board-certified, general anesthesiologist. Obstetric anesthesiologists then complete an additional year of study (fellowship) to gain specialized experience. Currently, obstetric anesthesia is not associated with an additional certification period over being board-certified in anesthesiology.


Ethical and medicolegal issues

Anesthesiologists use safe blood transfusions in certain situations as a therapy for patients with low oxygen carrying capacity or to correct coagulation problems. Certain religions (e.g.,
Jehovah's Witnesses Jehovah's Witnesses is a millenarian restorationist Christian denomination with nontrinitarian beliefs distinct from mainstream Christianity. The group reports a worldwide membership of approximately 8.7 million adherents involved in ...
) prohibit the use of blood transfusions based on their religious beliefs. Medical ethics stand on the four pillars of autonomy, beneficence, non-maleficence and justice. Based on the basis of patient autonomy, a person who is deemed to have capacity and refuses a blood transfusion for religious reason has the right to do so.


References

{{Reflist Anesthesiology specialties Obstetric surgery