I am going to do an all in one sticky of the old articles. SO if you want to look through and read each article will be on a seperate post therefore making it easier to distinguish. This way we have fewer sticky's on the page.
I am going to do an all in one sticky of the old articles. SO if you want to look through and read each article will be on a seperate post therefore making it easier to distinguish. This way we have fewer sticky's on the page.
Risks From Labor After Prior Cesarean Delivery Low, Study Reports
U.S. Department of Health and Human Services
National Institutes of Health
National Institute of Child Health and Human Development (NICHD)
Embargo Lifted by Journal
For Immediate Release
Tuesday, December 14, 2004
Robert Bock or Marianne Glass Miller
The risks from vaginal delivery after a prior Cesarean delivery are low, but are slightly higher than for a repeat Cesarean delivery. This finding is from the largest, most comprehensive study of its kind ever conducted, undertaken by the National Institute of Child Health and Human Development of the National Institutes of Health.
The study appears in the December 16 "New England Journal of Medicine."
"These findings provide women who have had a Cesarean delivery -- and their physicians -- with reliable information to take into account when deciding whether to undergo labor or to have a repeat Cesarean delivery," said Duane Alexander, M.D., Director of the NICHD.
Among the complications the study found in women who attempted a vaginal birth after prior Cesarean delivery were rupture of the uterus, infection of the uterine lining, lack of oxygen to the infant brain, and infant death. The study authors noted, however, that the risks of these complications were very low.
Cesarean delivery consists of delivering a baby through an incision made in the abdominal wall and through the uterus, rather than through the vagina. Reasons for Cesarean delivery include failure of labor to proceed normally, fetal heart rate abnormalities, and complications involving the placenta. Because cesarean delivery is a major surgical procedure, it carries the risks posed by any other major surgery, such as infection or complications from the anesthetic. Having a Cesarean delivery may also complicate future births.
Uterine rupture is the most well known complication of attempted vaginal delivery after a prior Cesarean delivery. Uterine rupture occurs when the scar in the uterine muscle opens. The rupture may result in part or all of the baby and perhaps the placenta leaving the uterus, which may cause fetal heart rate abnormalities and perhaps fetal death. A more severe, or catastrophic, rupture may result in heavy bleeding, which can endanger the lives of both mother and baby. In some cases, the bleeding may be so severe that a hysterectomy must be performed.
However, repeat Cesarean delivery also may carry risks beyond those posed bydelivering vaginally after a prior cesarean delivery, explained the NICHD author of the study, Catherine Spong, M.D., Chief of the Institute's Pregnancy and Perinatology Branch. The risk for infection and other surgical complications appear to be greater in women undergoing repeat cesarean delivery compared to those who are successful with a vaginal birth after Cesarean delivery.
Moreover, having a repeat cesarean delivery may complicate future pregnancies, sometimes causing the placenta to implant over the cervix, thereby interfering with the birth process. Prior Cesarean also increases the chances that the placenta will grow into the uterine wall, leading to difficulty with removal of the placenta after the birth. This may result in heavy bleeding during birth, perhaps leading to surgical removal of the uterus.
The decision of whether to attempt a vaginal delivery or to have a repeat Cesarean must be made carefully by women and their physicians. They must take into account, on the one hand, the risk of uterine rupture and its attendant
complications, and balance these factors against the risk of surgical complications and the chances that repeat Cesarean delivery might complicate future pregnancies.
Citing figures compiled by the National Center for Health Statistics (NCHS), the study authors noted that the rate of Cesarean delivery had increased from 5 percent in 1970 to an all time high of 26 percent in 2002. Recent preliminary data released by the NCHS indicated an overall Cesarean delivery rate exceeding 27 percent for 2003. For the same period, the rate of vaginal birth after Cesarean delivery had fallen from 31 percent in 1998 to 10.6 percent in 2003.
The U.S. Public Health Service, in its "Healthy People 2010 Report," proposed a target rate of vaginal birth after Cesarean delivery of 37 percent.
The NICHD Maternal-Fetal Medicine Units Network researchers undertook the current study to more precisely estimate the risks from vaginal birth after Cesarean delivery as compared to having a repeat Cesarean delivery. Before the current study, the only information on this topic was from studies that reviewed discharge codes from hospital records, Dr. Spong said. Such analyses, undertaken after the fact, may fail to include important information about the birth. Moreover, the few studies that had been conducted generally didn't include a large enough number of women for a reliable calculation of the risks involved.
The current study enrolled women at the 19 academic medical centers comprising the NICHD Maternal-Fetal Medicine Units Network. All of the women in the study were pregnant, and each had a previous Cesarean delivery. In all, 17,898 of the women attempted a vaginal birth and 15,801 underwent an elective repeat Cesarean delivery. Women were classified as having an elective Cesarean if they did not have a medical indication (need) for it and if they did not have labor.
Of the women who attempted a vaginal birth after cesarean delivery, only 0.7 percent, or 124 women in all, experienced a rupture of the uterus. The study also found that using drugs to induce or speed up labor may also increase the chances for uterine rupture. Such drugs increase the force and duration of uterine contractions. Of the 1864 women given the drug oxytocin alone, without any other drugs to induce labor, 1.1 percent (20 women) had a uterine rupture. None of the 227 women receiving the drugs known as prostaglandins alone experienced uterine rupture. Dr. Spong explained, however, that it's possible that the study sample did not include a sufficient number of women to determine a small increase in uterine rupture from prostaglandins alone.
Among the infants born to the women who attempted vaginal birth after a Cesarean, .08 percent (12) were diagnosed with hypoxic ischemic encephalopathy, a condition that may result from lack of oxygen to the baby's brain. The lack of oxygen may be caused by heavy maternal bleeding, detachment of the placenta, or other complications. Of these 12, seven were associated with a uterine rupture, and two of the babies died. In contrast, none of the infants whose mothers had an elective cesarean delivery developed hypoxic ischemic encephalopathy.
Among the women who attempted vaginal birth, the overall risk for either brain injury to the baby or death to the baby at term from uterine rupture was roughly 1 in 2000 trials of labor, said Mark B. Landon, M.D., of Ohio State University and the lead investigator for the NICHD Maternal-Fetal Medicine Units Network Cesarean Registry.
Women who attempted vaginal birth after cesarean were also more likely to develop infection of the uterine lining (2.9 percent) as compared to women who had an elective repeat Cesarean delivery (1.8 percent). The study authors found no significant difference between the percentage of women who required a hysterectomy: 0.2 percent in the labor group and 0.3 percent in the C-section group. Similarly, there was no significant difference in the maternal death rate between the two groups of women (.02 percent versus .04 percent.)
Dr. Spong said that the only way to arrive at a more accurate estimate of the risks involved would be to assign women at random to either a vaginal delivery or to have a repeat C-section. It's possible, she added, that the women who chose labor may differ in some unknown way from the women who had repeat Cesarean delivery, and that this difference might have influenced the study's results.
Still, Dr. Spong said, because of the large number of women who took part in study, and the careful, systematic way the researchers collected the data, the current study offers the most reliable estimate to date of the risks conveyed by attempting vaginal delivery after a prior Cesarean delivery.
The NICHD is part of the National Institutes of Health (NIH), the biomedical research arm of the federal government. NIH is an agency of the U.S. Department of Health and Human Services. The NICHD sponsors research on development, before and after birth; maternal, child, and family health; reproductive biology and population issues; and medical rehabilitation. NICHD publications, as well as information about the Institute, are available from the NICHD Web site, <http://www.nichd.nih.gov>, or from the NICHD Information Resource Center, 1-800-370-2943; e-mail NICHDInformationResourceCenter@mail.nih.gov.
What is a uterine scar rupture?
A complete uterine scar rupture is a potentially life threatening condition for both the mother and/or the baby that requires immediate surgical intervention. Fortunately, uterine ruptures from a prior cesarean with a low-transverse scar is a rare event and occurs in less than 1% of women laboring for a VBAC. It is a tear through the thickness of the uterine wall at the site of a prior cesarean incision. The majority of cesarean uterine incisions are low-transverse. The scar form this type of incision is the least likely to rupture in a subsequent pregnancy, labor, and birth.
Uterine ruptures have also been known to occur in some women who have never had a cesarean. This type of rupture can be caused by weak uterine muscles after several pregnancies, excessive use of labor inducing agents, prior surgical procedure on the uterus, or mid-pelvic use of forceps.
Some women have a low vertical incision on the uterus, made when there is a placenta previa (low-lying placenta), a large baby, a baby in a transverse position (lying horizontally in the pelvis) or a premature breech delivery.
When planning a VBAC it is important to determine if the previous low vertical scar has not stretched to the body of the uterus in the current pregnancy. The risk of rupture for a low vertical scar has been reported to be the same as for a low horizontal scar and as high as 1-7%.
Sometimes a woman may have a "T" or "J" shaped scar on the uterus or one that resembles an inverted "T". These scars are very rare. It is estimated that between 4 and 9% of "T" shaped uterine scars are at risk for rupture.
Rarely, a woman may have a classical (vertical) scar in the upper part (the body) of the uterus. This type of incision is used for babies who are in a breech or transverse position, for women who may have a uterine malformation, for premature babies or in extreme circumstances when time is of the essence.
The risk of rupture for this type of scar has been reported to be between 4% and 9%. A classical scar on the thinner and more vulnerable part of the uterus tends to rupture with more intensity and result in more serious complications for mothers and babies. Mothers who have had several children and have a classical uterine scar are at higher risk for uterine rupture.
The American College of Obstetricians and Gynecologists (ACOG), the Society of Obstetricians and Gynecologists of Canada (SOGC) and the Royal College of Obstetricians and Gynaecologists (RCOG) of Britain recommend that women with a classical scar have a repeat cesarean birth.
What are the symptoms of a uterine rupture?
A uterine rupture cannot be accurately predicted or diagnosed before it actually occurs. It can occur suddenly during labor or delivery. A few studies have suggested that measuring the thickness of the scar by ultrasound or following closely the pattern of contractions in labor may be useful in anticipating and therefore preventing a scar rupture. However, there is not enough information to prove that these methods should be widely adopted.
Several symptoms have been identified, but do not necessarily occur with every uterine rupture. Signs of uterine rupture that may or may not be present.
Sharp pain between contractions
Contractions that slow down or become less intense
Abdominal pain or tenderness
Recession of the fetal head (baby's head moving back up into the birth canal)
Bulging under the pubic bone (baby's head has protruded outside of the uterine scar)
Sharp onset of pain at the site of the previous scar Uterine atony (soft muscles)
To date, studies have shown that a uterine rupture can be detected by electronic fetal monitoring (EFM) because the women in these studies laboring for a VBAC were monitored electronically. Although some caregivers closely monitor VBAC labors with a fetoscope or a hand-held ultrasound measuring device (the Doppler), no VBAC studies have yet been published on this method. Guidelines from the ACOG, SOGC, and RCOG recommend that women laboring for a VBAC be offered electronic fetal monitoring.
Abnormal fetal heart tones, variable decelerations, or bradycardia (slow heart rate) have been associated with a uterine rupture. It is important to note that with a uterine rupture, labor sometimes continues, there is no loss of uterine tone or amplitude of contractions.
How often does a cesarean scar rupture occur?
For women who had a prior cesarean birth the rupture can occur at the site of the previous uterine scar. Dozens of studies report that for women who have had one prior cesarean birth with a low-horizontal incision, the risk of uterine rupture is 0.5% to 1.0%. A woman who has had more than one cesarean with a low horizontal incision may have a slightly higher risk of rupture. One study that looked at the risks of uterine rupture for planned VBACs over a ten-year period at a teaching hospital that was often able to perform an emergency cesarean very quickly found the following results:
Risk of Uterine Rupture with Low Transverse Uterine Scars* Revised 10/14/2002
Number of Previous Cesareans
10,880 Planned VBACs with one prior scar
1,586 Planned VBACs with two prior scars
241 Planned VBACs with three prior scars
Source: Miller, D. A., F. G. Diaz, and R. H. Paul.1994. Obstet Gynecol 84 (2): 255-258
*This study included women with breech babies and twins and use of oxytocin.
How does the risk of a rupture compare with any other complications of labor whether the mother had a prior cesarean birth or not?
For women whose labors begin spontaneously, uterine rupture is reported to be less than 1% and the risks similar to or less than the risk of any other unpredictable complication of labor and delivery.
Medical experts state that the risk of a uterine rupture with one prior low-horizontal incision is not higher than any other unforeseen complication that can occur in labor such as fetal distress, maternal hemorrhage from a premature separation of the placenta or a prolapsed umbilical cord.
Respected studies have concluded that the probability of any woman needing to have an emergency cesarean those other complications is approximately 2.7% or up to 30 times as high as the risk of uterine rupture.
For the year 2000, for approximately 4 million live births, the US National Center for Health Statistics reported the following complications that occurred during labor and birth: The table below compares the risks of a uterine rupture (with one low-transverse scar) with the risks of other unpredictable complications of labor and birth.
Reported Complications of Labor and Delivery in US for year 2000 Rate per 1000 live births
Umbilical Cord Prolapse
Source: CDC: NCHS: Births: Final Data for 2000
Uterine rupture rate per 100 women laboring for a VBAC, based on worldwide systematic reviews (0.09 to 0.8 %)
Source: Enkin et all 2000. A Guide to Effective Care in Pregnancy and Childbirth.
Data from the Vermont/New Hampshire VBAC Project shows a risk for uterine rupture to be 5 per 1,000 for women who labor for a VBAC compared to 2 per 1,000 for women who have a planned cesarean birth. The RCOG in Britain states that uterine rupture is a very rare complication, but is increased in women who labor for a VBAC (35 per 10,000) compared to women who have a planned repeat cesarean (12 per 10,000).
What happens if the scar ruptures?
Although uterine scar ruptures for women laboring for a VBAC are rare, the medical response is a rapid cesarean.
The longer it takes to diagnose and respond to a uterine rupture the more likely it is that the baby and/or the placenta can be pushed through the uterine wall and into the mother's abdominal cavity putting women at increased risk for hemorrhage and babies at increased risk for neurological complications and very rarely, death.
The authors of A Guide to Pregnancy and Childbirth, an internationally respected evidence-based text, state that any birthing facility equipped to respond to a medical emergency can care for women laboring for a VBAC.
Whereas ACOG guidelines for an emergency cesarean previously allowed for a maximum response time of 30 minutes for an obstetric emergency controversial VBAC guidelines revised by ACOG (1999 and 2004) have recommended that birth facilities who care for women laboring for a VBAC should have a physician capable of performing an emergency cesarean, anesthesia services, and staff "immediately available." The SOGC recommends "urgent attention and expedited laparotomy [surgical incision into the abdominal cavity]" when a uterine rupture is suspected. The RCOG recommendations are “immediate access to a cesarean section and on-site blood transfusion services."
Birthing facilities vary in their guidelines and protocols for VBAC and response time to a uterine rupture and other unforeseen complications of labor. Many US facilities have recently determined that they don't have the capability to respond "immediately" in case of uterine scar rupture and are currently denying women the option to labor for a VBAC.
Caregivers who support VBACs say that the focus should be on improving access to quality of care for women who want a VBAC, not on discouraging them because of negative outcomes publicized in high profile medical malpractice law suits.
Dr. Bruce L. Flamm, an eminent researcher on VBACs cautioned that if US physicians were to discourage women from planning VBACs and to adopt a policy of elective repeat cesareans, it "would mean performing an additional 100,000 cesareans every year. It is unlikely this huge number of operations could be performed without many serious complications and perhaps even some maternal deaths."
In the event of a uterine rupture, what are the outcomes for mothers and babies?
The majority of studies report that in the rare event of a uterine rupture, if the labor was carefully monitored, the birth attendant was trained to attend VBAC births, and if the medical response was rapid, mothers and babies usually do well. One study in a large California hospital which had 24 hour emergency coverage reported that outcomes for babies were better when the response time was 18 minutes or less.
With access to a rapid cesarean, fetal death from a uterine rupture is an extremely rare event. Three large studies that determined the number of babies who died as a direct result from a uterine rupture when women labored for a VBAC found the following:
Number of women who labored for a VBAC
Number of babies who died from uterine rupture
Rageth, et al 2000
Rosen, et al 1991
Flamm, et al 1994
The Vermont/New Hampshire VBAC Project findings show the overall risk of infant death from a VBAC attempt is 6 per 10,000 compared to 3 per 10,000 planned cesarean births.
Women who receive good prenatal care, whose care providers are trained and experienced with VBAC, and who labor in a facility that is equipped to provide immediate medical care usually have good outcomes.
Women who are thinking about laboring for a VBAC at home may want to consider and make plans for the possibility of a uterine rupture. Home VBACs are not recommended by the US, Canadian, or UK professional guidelines.
Women thinking about laboring for a VBAC in a free-standing birth center may also want want to consider making plans to access emergency services in the event of a uterine rupture.
To find out more about VBACs in accredited birth centers in the USA contact the National Association of Childbearing Centers at www.birthcenters.org.
Can the risk for a uterine rupture be reduced?
Although it is not possible to predict which women are likely to experience a uterine rupture while laboring for a VBAC, recent studies have suggested that the risk for uterine rupture is higher when:
Labor is induced with oxytocin, prostaglandin preparations, or misoprostol (Cytotec).
The prior cesarean incision was closed with a single-layer of sutures (single-layer closure- often done in recent years to shorten the time in the operating room) as opposed to two layers of sutures (double-layer closure).
Women become pregnant and labor for a VBAC within less than 24 months after a prior cesarean.
Women are older than 30 years of age.
Maternal fever was a consequence of a prior cesarean birth.
A classical uterine incision was used in a prior cesarean birth.
A woman has had two or more prior cesarean births.
According to ACOG, prostaglandins for induction of labor in most women with a previous cesarean should be discouraged. Similarly, the SOGC states that misoprostol "is associated with a high risk of uterine rupture and should not be used" when women labor for a VBAC.
Informed Choice-Informed Refusal
Current US health law and medical-ethical guidelines give childbearing women who once gave birth by cesarean the option of laboring for a VBAC or scheduling an elective repeat cesarean. ACOG states that
"it has become clear that patients are entitled to participate with their physicians in a process of shared decision making with regard to medical procedures, tests, or treatments"; Once the patient has been informed of the material risks, and benefits involved ; that patient has the right to exercise full autonomy in deciding whether to undergo the treatment, test, or procedure or whether to make a choice among a variety of treatments, tests, or procedures. In the exercise of that autonomy, the informed patient also has the right to refuse to undergo any of these treatments, tests, or procedures. This election by the patient to forgo a treatment, test, or procedure that has been offered or recommended by the physician constitutes informed refusal."
Women are encouraged to ask questions, gather information, and discuss their concerns with their care providers to enable them to make an informed choice for a VBAC or a repeat cesarean birth.
For additional information see Making Informed Decisions, Patient Rights and The Vermont/New Hampshire VBAC Project.
American College of Obstetricians and Gynecologists (ACOG) July 1999. Vaginal Birth After Previous Cesarean Delivery Practice Guidelines. Practice Bulletin Number 5.
American College of Obstetricians and Gynecologists (ACOG) July 2004. Vaginal Birth After Previous Cesarean Delivery Practice Guidelines. Practice Bulletin Number 54.
Bujold, E. et al. 2002. American Journal of Obstetrics and Gynecology 86 (6) :1326-30.
Enkin et al 2000. Effective Care in Pregnancy and Childbirth.
Flamm, Bruce. 1990. Birth After Cesarean, a consumer guide book.
Flamm, B. and E.J. Quilligan, Editors 1995. Cesarean Section Guidelines: Appropriate Utilization.
Flamm, B.L. 1997. Obstetrics and Gynecology 90 (2):312-315.
Institute for Clinical Systems Improvement 1998. Health Care Guidelines G32. Vaginal Birth After Cesarean. On-line www.icsi.org/guide.
Leung, A.S., E.k. Leung, and R. H. Paul 1993. American Journal of Obstetrics and Gynecology 169(4): 945-50.
Lydon-Rochelle, M. et al 2001. New England Journal of Medicine 345(1):3-8. Norther New England OB Group 2003. Birth Choices After Cesarean, from the Vermont/New Hampshire VBAC Project. Available free from .....
Rageth, J.C., C. Juzi, and H. Grossenbacher 1999. Obstetrics and Gynecology 93(3):332-337.
Shipp, TD et al 2001. Obstetrics and Gynecology 97(2):175-77.
Society of Obstetricians and Gynaecologists of Canada, December1997. Clinical Practice Guidelines Policy Statement: Vaginal Birth After Previous Cesarean Birth. (Number 6. [acrobat pdf]
Society of Obstetricians and Gynaecologists of Canada, December1997. Clinical Practice Guidelines Policy Statement: Vaginal Birth After Previous Cesarean Birth. (Number 147). [acrobat pdf]
Zelop, C.M. et al 1999. American Journal of Obstetrics and Gynecology 181(4):882-6.
Epidurals and Planned VBAC
Some studies have shown that epidural analgesia for labor increases the risk for cesarean delivery, others have not. The latest evidence from controlled studies shows that use of epidurals does not increase the risk for cesarean for women laboring for a VBAC, nor does it mask the pain or tenderness in the rare event of a uterine rupture.
Epidural analgesia for labor varies widely based on the type of drug used, the combination of drugs, the dose, the stage of labor at which it is introduced, the woman's ability to change positions in labor, and how much time a woman is given to complete her labor.
For the most up-to-date information on use of epidurals for pain relief, see Maternity Center Association's Advice on Labor Pain Relief and Effect of Labor Pain Medication Timing on Cesarean Section: NEJM Study, 2/2005
What is an epidural?
Epidural analgesia is a way of providing pain relief for labor by inserting medication into the epidural space located near the spine through a thin plastic tube. The medication numbs the nerves of the uterus and the birth canal. The mother feels the numbing effect from the waist area down to the thighs, and sometimes to the toes. The lighter the dose of anesthetic the easier it is for the mother to move around.
What is the advantage of using an epidural?
An epidural allows the mother stay alert throughout labor and delivery.
The baby is less heavily medicated.
It can provide a rest period when labor is long.
It can provide pain relief when labor is induced or augmented with pitocin.
What drugs are used?
The drugs used are often a combination of an anesthetic (such as bupivacaine) and a narcotic or opioid (such as fentanyl). The combination of drugs used and the dosage vary depending on the anesthesiologist or nurse anesthetist. For more information about drugs in pregnancy and birth see Drugs & Pregnancy.
How is the procedure done?
The mother must have an adequate amount of intravenous fluid, an IV line is inserted.
The mother's blood pressure and the baby's heart rate are monitored at all times.
The mother is placed on her side or asked to sit up and lean forward.
The anesthesiologist or nurse anesthetist bathes an area in the lower back with a cleansing solution.
A local anesthetic is injected, then an epidural needle is slowly inserted between two vertebras till it reaches the epidural space, just before the membrane that covers the spinal cord.
The mother usually feels pressure at this time.
An epidural catheter, thin plastic tube, is slowly threaded into the epidural space and the needle removed.
The catheter, which feeds the medication into the space, is taped to the mother's back.
The mother begins to feel pain relief in about 10 to 20 minutes. Her legs may feel warm or tingly and may feel heavy.
The lighter the anesthetic dose, the more flexibility the mother has to move her legs and the easier it is to change positions.
Are there any side effects?
Epidural analgesia is usually a safe procedure, but it may carry some risks.
A woman's ability to move around or change positions may be limited.
The medication in the epidural may cause an erratic heart rate for the baby. Local anesthetics rapidly cross the placenta.
Drugs can cause various degrees of maternal, fetal, and neonatal toxicity.
Studies show that use of epidural analgesia:
May slow down labor.
May increase the possibility for using pitocin.
May make it more difficult for the mother to push the baby down.
May increase the likelihood of using forceps or a vacuum extractor.
May cause maternal fever when used for long hours.
May make it more likely that the newborn will be screened and treated for infection.
Some mothers experience nausea, vomiting or itching when epidural narcotics are used.
May cause short-term urinary incontinence.
Is there a best time to ask for an epidural?
Some studies have shown that the risk for cesarean is reduced if the epidural is started after the baby's head is engaged in the pelvis and the mother waits until the cervix is dilated to 4-5 centimeters.
For more information about epidural anesthesia for labor see American Society of Anesthesiologists - Standards Guidelines and Statements.
Non-Pharmacological Methods of Pain Relief
The latest research shows that several methods, other than use of medication, are effective in reducing pain in labor.
Moving and changing positions for labor and birth.
Use of Touch (handholding, stroking, patting) and Massage.
Immersion in water during active labor (as opposed to early labor) when the water is maintained at body temperature.
Use of Intradermal Water Blocks (subcutaneous injections of sterile water).
Continuous Labor Support by an experienced person (who provides physical comfort, such as relaxation techniques, massage, non-clinical information and advice for the laboring woman and her partner, advise on effective positions, heat or cold for pain relief, and emotional support (encouragement and reassurance).
Enkin, et al 2000. A Guide to Effective Care in Pregnancy and Childbirth. Oxford University Press.
New York Academy of Medicine and Maternity Center Association. The Nature and Management of Labor Pain: An Evidence-Based Symposium. May 4-5, 2001. New York, NY.
Lieberman , E. 1999. No free lunch on labor day: The risks and benefits of epidural analgesia during labor. Journal of Nurse-Midwifery, 44(4):394-398.