to augment uterine contractions. in one study which examined the rate of breastfeeding two days following epidural anesthesia during childbirth, epidural analgesia used in combination with oxytocin resulted in lower maternal oxytocin and prolactin levels in response to breastfeeding on the second day following birth. this results in a decrease in the amount of milk produced. technique anatomy sagittal section of the spinal column (not drawn to scale). yellow: spinal cord; blue: pia mater; red: arachnoid; light blue: subarachnoid space; pink: dura mater; pale green: epidural space; taupe: vertebral bones; teal: interspinous ligaments main article: epidural space an epidural is injected into the epidural space, inside the bony spinal canal but just outside the dura. in contact with the inner surface of the dura is another membrane called the arachnoid mater, which contains the cerebrospinal fluid. in adults, the spinal cord terminates around the level of the disc between l1 and l2, while in neonates it extends to l3 but can reach as low as l4. below the spinal cord there is a bundle of nerves known as the cauda equina or "horse's tail". hence, lumbar epidural injections carry a low risk of injuring the spinal cord. insertion of an epidural needle involves threading a needle between the bones, through the ligaments and into the epidural space without puncturing the layer immediately below containing csf under pressure. insertion simulation of the insertion of an epidural needle between the spinous processes of the lumbar vertebrae. a syringe is connected to the epidural needle and the epidural space is identified by a technique to assess loss of resistance epidural administration is a procedure which requires the person performing the insertion to be technically proficient in order to avoid complications. proficiency may be trained using bananas or other fruits as a model. the person receiving the epidural may be seated, or lying on their side or stomach. the level of the spine at which the catheter is placed depends mainly on the site of intended operation – based on the location of the pain. the iliac crest is a commonly used anatomical landmark for lumbar epidural injections, as this level roughly corresponds with the fourth lumbar vertebra, which is usually well below the termination of the spinal cord. the tuohy needle, designed with a 90-degree curved tip and side hole to redirect the inserted catheter vertically along the axis of the spine, may be inserted in the midline, between the spinous processes. when using a paramedian approach, the tip of the needle passes along a shelf of vertebral bone called the lamina until just before reaching the ligamentum flavum and the epidural space. along with a sudden loss of resistance to pressure on the plunger of the syringe, a slight clicking sensation may be felt by the operator as the tip of the needle breaches the ligamentum flavum and enters the epidural space. saline or air may be used to identify placement in the epidural space. a systematic review from 2014 showed no difference in terms of safety or efficacy between the use of saline and air for this purpose. in addition to the loss of resistance technique, direct imaging of the placement may be used. this may be conducted with a portable ultrasound scanner or fluoroscopy (moving x-ray pictures). after placement of the tip of the needle, a catheter or small tube is threaded through the needle into the epidural space. the needle is then withdrawn over the catheter. the catheter is generally inserted 4–6 cm into the epidural space, and is typically secured to the skin with adhesive tape, similar to an intravenous line. use and removal if a short duration of action is desired, a single dose of medication called a bolus may be administered. thereafter, this bolus may be repeated if necessary provided the catheter remains undisturbed. for a prolonged effect, a continuous infusion of medication may be used. there is some evidence that an automated intermittent bolus technique may provide better pain control than a continuous infusion technique even when the total doses administered are identical. typically, the effects of the epidural block are noted below a specific level or portion of the body, determined by the site of injection. a higher injection may result in sparing of nerve function in the lower spinal nerves. for example, a thoracic epidural performed for upper abdominal surgery may not have any effect on the area surrounding the genitals or pelvic organs. combined spinal-epidural techniques main article: combined spinal and epidural anesthesia for some procedures where both the rapid onset of a spinal anesthetic and the post-operative analgesic effects of an epidural are desired, both techniques may be used in combination. this is called combined spinal and epidural anesthesia (cse). the spinal anesthetic may be administered in one location, and the epidural at an adjacent location. alternatively, after locating the epidural space with the tuohy needle, a spinal needle may be inserted through the tuohy needle into the subarachnoid space. the spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. this method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space. recovery epidural analgesia is generally well tolerated, with recovery time quick after administration is complete and the epidural is removed. the epidural catheter is usually removed when it is possible to safely switch to oral administration of medications, though catheters can safely remain in place for several days with little risk of bacterial infection, particularly if the skin is prepared with a chlorhexidine solution. subcutaneously tunneled epidural catheters may be safely left in place for longer periods, with a low risk of infection or other complications. regardless of the length of use, the effects of a medicine administered epidurally, including numbness if used for analgesia, usually wear off within a few hours of the epidural being stopped, with full recovery of normal function within 24 hours. the use of epidural analgesia during a birth does not have any effect on whether a caesarean section must be performed during future births. epidural analgesia during childbirth also generally has no negative effects on the long-term health of the mother or child. use of epidural analgesia versus oral analgesia or no analgesia has no effect on the normal length of hospital stay after childbirth, the only difference being that care must be performed around the epidural insertion site to prevent infection. following epidural analgesia used for gastrointestinal surgery, the time to recovery of normal gastrointestinal function is not significantly different from recovery time after intravenous analgesia. the use of epidural analgesia during cardiac surgeries may shorten the amount of time a person requires ventilator support following surgery, but it is unknown whether it shortens the overall post-surgery hospital stay overall. history spanish doctor fidel pagés visiting injured soldiers at the docker hospital in melilla in 1909. the first record of an epidural injection is from 1885, when american neurologist james corning of acorn hall in morristown, nj used the technique to perform a neuraxial blockade. corning inadvertently injected 111 mg of cocaine into the epidural space of a healthy male volunteer, although at the time he believed he was injecting it into the subarachnoid space. following this, in 1901 fernand cathelin first reported intentionally blocking the lowest sacral and coccygeal nerves through the epidural space by injecting local anesthetic through the sacral hiatus. the loss of resistance technique was first described by achile dogliotti in 1933, following which alberto gutiérrez described the hanging drop technique. both techniques are now used to identify when the needle has correctly been placed in the epidural space. in 1921 fidel pagés, a military surgeon from spain, developed the technique of "single-shot" lumbar epidural anesthesia, which was later popularized by italian surgeon achille mario dogliotti. later, in 1931 eugen aburel described using a continuous epidural catheter for pain relief during childbirth. in 1941, robert hingson and waldo edwards recorded the use of continuous caudal anesthesia using an indwelling needle, following which they described the use of a flexible catheter for continuous caudal anesthesia in a woman in labor in 1942. in 1947, manuel curbelo described placement of a lumbar epidural catheter, and in 1979, behar reported the first use of an epidural to administer narcotics. society and culture some people continue to be concerned that women who are administered epidural analgesia during labor are more likely to require a cesarean delivery, based on older observational studies. however, evidence has shown that the use of epidural analgesia during labor does not have any statistically significant effect on the necessity to perform a cesarean delivery. a 2018 cochrane review found no increase in the rate of caesarean delivery when epidural analgesia was employed. however, epidural analgesia does lengthen the second stage of labor by 15 to 30 minutes, which may increase the risk a delivery must be assisted by instruments. in the united states in 1998, it was reported that over half of childbirths involved the use of epidural analgesia, and by 2008 this had increased to 61% of births. in the united kingdom, epidurals have been offered through the national health service for all women during childbirth since 1980. by 1998, epidural analgesia was used in the uk for almost 25% of childbirths. in japan, most childbirths take place in primary or secondary hospitals in which epidural analgesia is not offered. in some developed countries, over 70% of childbirths involve epidural analgesia. other studies have shown that minority women and immigrants are less likely to receive epidural analgesia during childbirth. even in countries with universal healthcare coverage such as canada, socioeconomic factors such as race, financial stability, and education influence the rate at which women receive epidural analgesia. one survey in 2014 found that over half of pregnant women in a nigerian antenatal clinic (79.5%) did not know what epidural analgesia was or what it was used for, while 76.5% of them would utilize epidural analgesia if offered after it was explained to them.