CLINICAL OBSTETRICS AND GYNECOLOGY Volume 58, Number 2, 282–293 Copyright r 2015 Wolters Kluwer Health, Inc. All rights reserved.
Preventing Primary Cesarean Births: Midwifery Care KIM J. COX, PhD, CNM,* and TEKOA L. KING, MPH, CNMw *College of Nursing, University of New Mexico, Albuquerque, New Mexico; and w Health Sciences Clinical Professor, School of Nursing, University of California, San Francisco, California
Abstract: The incidence of cesarean birth in the United States is alarmingly high and cesareans are associated with added morbidities for women and newborns. Thus strategies to prevent cesarean particularly for low-risk, nulliparous women at term with a singleton fetus are needed. This article addresses evidence-based practices that may be used during intrapartum to avoid primary cesarean, including patience with progress in labor, intermittent auscultation, continuous labor support, upright positions, and free mobility. Second-stage labor practices, such delayed pushing and manual rotation of the fetus, are also reviewed. This package of midwifery-style care practices can potentially lower primary cesarean rates. Key words: cesarean birth, prevention, dystocia, intermittent auscultation, continuous labor support, mobility in labor
among US states, from 22.6% (Alaska) to 38.8% (New Jersey).2 Although cesarean birth can be life saving for a woman or her fetus, the sharp increase in cesarean rates over the past 2 decades was not accompanied by a decrease in either neonatal or maternal morbidity or mortality.3 Furthermore, the wide variation in cesarean rates among hospitals and states across the country for nulliparous women at term with a singleton vertex fetus (NTSV) at the onset of labor suggests that clinical practice patterns may play a role, particularly for common indications, such as dystocia and abnormal or indeterminate fetal heart rate (FHR) tracing.3 In response to this problem, the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) published a consensus statement in March 2014.3 The article raised the concern that primary cesarean has been overused and that efforts should be directed toward safely decreasing current rates. Two of the most common indications for which management may be modified include dystocia and abnormal or indeterminate
Introduction In 2013, one third (32.7%) of the 4 million women who gave birth in the United States had a cesarean section.1 Cesarean rates increased by 60% overall from 1996 to 2011, although rates varied widely Correspondence: Kim J. Cox, PhD, CNM, College of Nursing, University of New Mexico, MSC, Albuquerque, NM. E-mail: [email protected] The authors declare that they have nothing to disclose. CLINICAL OBSTETRICS AND GYNECOLOGY
282 | www.clinicalobgyn.com
/
VOLUME 58
/
NUMBER 2
/
JUNE 2015
Preventing Primary Cesarean Births FHR tracings.3 This article reviews the evidence regarding labor management practices that are associated with midwifery care and lower cesarean rates. We offer suggestions that may be helpful in reducing the primary cesarean rate in nulliparous women at term.
Background Considering the effect on future pregnancies, it is important to understand the drivers behind primary cesarean rates and attempt to reduce them. This is particularly important for low-risk NTSV women, as they are the cohort of women who should be the least likely to have a cesarean birth. Moreover, the primary cesarean rate is a key indicator of health care quality in this group.4 One important factor is the wide variation in cesarean rates from hospital to hospital and from state to state. In 2013, the primary cesarean rate was 21.5% nationally, with a low of 13% in Utah to a high of 27% in Florida and Louisiana.1 Because maternal characteristics, such as age, weight, and ethnicity, do not adequately account for the differences in rates,5 variations in practice, providers, and patient preferences are likely to play a role. Another factor is the indication for the cesarean birth. In population-based studies, >50% of primary cesareans were performed for dystocia or abnormal or indeterminate FHR tracing.6,7 Dystocia, the leading indication, is problematic for several reasons. Many hospitals and providers still use the Friedman Curve to assess labor progress. More recent research by the Consortium on Safe Labor, however, has demonstrated that labor progression is slower than what was previously thought.6,8 Contemporary labor practices, such as epidural anesthesia, induction, laboring in bed, and frequent use of oxytocin (Pitocin; JHP Pharmaceuticals, Parsippany, NJ) differ substantially from labor management in Friedman’s day.3 Furthermore, there are a number of evidence-based labor
283
practices that are already in use by midwives during first-stage and second-stage labor that could be helpful in decreasing the diagnosis of dystocia. These practices include patience with progress in the first stage of labor, intermittent auscultation (IA) for low-risk women, continuous labor support, doula care, and encouraging upright positions and free mobility throughout labor. Second-stage labor practices, such as extended duration of the second stage, delayed pushing, and manual rotation of the fetus, are also reviewed. The article concludes with an exploration of how a ‘‘package’’ of midwifery-style care practices can potentially influence primary cesarean rates.
Dystocia: 6 is the New 4 Dystocia is the leading cause of primary cesarean sections today, accounting for approximately half of those performed during labor.6 Dystocia also accounts for the greatest variation in institutional cesarean rates.4 In most labor and delivery settings, women’s labor progress is measured against the Friedman curve to determine normal progress and to diagnose dystocia or arrest of labor. The genesis of this curve is worth reviewing. Dr Emanuel Friedman identified the Friedman curve in the 1950s. He measured the progress of 500 primigravid women to determine the mean, median, range, and SD of the first stage of labor. He divided the calculated sigmoid curve into the latent, active, and transition phases ‘‘for purposes of mathematical simplification.’’9(p569) The Friedman curve is not a good template for women in labor today for several reasons. First, Friedman’s calculations were based on a cohort of women who were different from the population of women who give birth in the United States today. For example, women today are more likely to be obese and older, the racial and ethnic diversity is more robust, and labor practices that affect the duration of labor are different than they were 50 years ago.8,10–14 Second, the mathematical www.clinicalobgyn.com
284
Cox and King
TABLE 1.
Normal Labor Progress in Nulliparous Women at Term in Spontaneous Labor
References N 9
Friedman 500
Albers10
Key Findings
Clinical Implications
Mean active phase was 2.5 h
Care practices that independently affect labor length were used in the 1950s that are no longer part of normal intrapartum care; the Friedman curve should not be used to monitor labor progress Use of IA and ambulation during active labor in women without analgesia may shorten length of the first stage of labor
2511
Mean active phase duration was 7.7 h (17.5 h SD) Midwifery-managed care; 43.7% used EFM, 61% were ambulatory in labor; EFM and ambulation were associated with longer labors Zhang 1329 Mean duration of active phase was 5.5 h et al11 (95% 13.7 h) Marked inter-individual variability in cm at which active phase starts (3-5 cm) Time interval of no change >2 h not uncommon before 7 cm Neal 7009 Mean duration of active phase was 6 h et al12 (13.4 SD); systematic review included studies of women with analgesia and oxytocin augmentation; slowest normal rate of cervical dilation approximates 0.5-0.6 cm/h Laughton 27,471 Median duration of active phase: et al13 4-6 cm: 6.5 h (95% 24 h) 5-6 cm: 3.6 h (95% 15.1 h) 6-C/C: 1.2 h (95% 10 h) Neal 216 Comparison of women admitted in latent et al14 vs. active labor Median duration of active phase was 9.5 h in women admitted in latent phase and 5.8 h in women admitted in active labor Likelihood of cesarean section was higher in the women admitted in latent labor (OR = 2.6; 95% CI, 1.02-6.37)
Allow at least 2 h between each increment of cervical dilation before 7 cm
Allow at least 2 h between each increment of cervical dilation in late active phase of labor
Duration of active phase shortens when interval comparison between each degree of dilatation is compared Avoid admission or initiation of obstetric interventions for women who are in latent labor
C/C indicates completely effaced and completely dilated; CI, confidence interval; EFM, electronic fetal monitoring; IA, intermittent auscultation; OR, odds ratio.
averaging used to create the Friedman curve blunted some very important distinctions in how women progress from 1 cervical dilation to the next.8 Recently, Zhang and colleagues reanalyzed labor progress using data from the National Collaborative Perinatal Project. The National Collaborative Perinatal Project is a large prospective study of women who gave birth between 1955 and 1966, when intrapartum management was similar to the management experienced by the women in Friedman’s sample. Using a www.clinicalobgyn.com
repeated-measures analysis, Zhang et al8 found that the latent phase of labor lasted longer than Friedman detected and that a deceleration phase did not occur. Subsequently, several researchers have used contemporary data to examine labor progress in women who give birth today. Table 1 summarizes the results of recent studies on labor progress in nulliparous women at term.9–14 Table 2 presents a small sample of the current research on differences in labor progress for specific populations.15–17 In summary, use of the Friedman curve to
Preventing Primary Cesarean Births TABLE 2.
Labor Progress Duration in Subpopulations of Women
References Population
Albers et al15
Norman et al16
Zaki et al17
285
Key Findings
Clinical Implications
N = 1473 low-risk women at term Hispanic, nonwith and without analgesia and Hispanic white, labor interventions, cared for by and Native nurse-midwives American Length of active phase of labor was not different in Hispanic and American Indian women compared with non-Hispanic white women Length of second stage was significantly shorter in Native American women compared with non-Hispanic white women Increased BMI 5204 nulliparous and multiparous women; adjusted for parity, labor type, race, and birth weight Labor duration is longer in women with a BMI>30 (OR = 4.7 vs. 4.1 h, P40 have approximately 2 h longer first stage of labor compared with women with a BMI of r25 Maternal age maybe considered when assessing normal progress in the active phase of labor
BMI indicates body mass index; OR, odds ratio.
determine the limits of normal is resulting in overdiagnosis of dystocia when women are still in latent labor, which results in overutilization of cesarean section. Until an improved labor partogram is developed and validated for clinical use, the Friedman curve should be abandoned and the summary points highlighted in the accompanying tables used as benchmarks for managing women’s labor progress.
IA for FHR Monitoring Approximately 20% to 30% of all NTSV cesareans are performed for fetal intolerance of labor.4 Although 90% of women who give birth in the United States undergo
continuous electronic fetal heart rate monitoring (EFM),18 interpretation of variant FHR patterns has a high false-positive rate. Therefore, continuous EFM is a poor screening tool for identification of fetal acidemia. EFM was adopted into clinical practice in the 1960s, before the technology was evaluated for clinical utility. Subsequently, several randomized-controlled trials (RCTs) were conducted that compared EFM with IA, and the most recent Cochrane meta-analysis of this body of work has confirmed that EFM is associated with higher cesarean section rates compared with IA without improvement in Apgar scores, perinatal mortality, or rates of cerebral palsy.19 It is important to remember www.clinicalobgyn.com
286
Cox and King
that the Cochrane results did not show either EFM or IA to be superior for identification of fetal acidemia. Therefore, because EFM is associated with a higher cesarean section rate, it is of value in reassessing the effectiveness of IA. Ideally, the effectiveness of IA would be best determined by conducting an RCT that compared IA with no monitoring or IA with another form of fetal monitoring. However, it would be unethical to randomize women to no fetal monitoring during labor. RCTs are also unlikely to be performed because very large numbers of laboring women would need to participate to detect a real difference in perinatal mortality, and this magnitude of study is difficult to achieve. However, evidence that supports the use of IA is available. EFFECTIVENESS OF IA
IA is standard practice for monitoring the fetus during labor in free-standing birth centers. The maternal and newborn outcomes for women who give birth in these settings are exceptionally good overall, which provides some indirect evidence that IA is part of a process of care that provides effective screening for developing fetal acidemia.20,21 In addition, women who give birth in free-standing birth centers have lower cesarean section rates than do women who have a similar a priori risk for fetal acidemia and who give birth in hospital settings.22 Finally, 1 real critique of the RCTs comparing IA with EFM is that those studies are now more than 30 years old, when knowledge of the physiology of the FHR in labor was not as well known as it is today.23 A current, albeit small, study of IA used in a hospital setting showed that the women who received IA had a lower incidence of cesarean birth than did women who were monitored continuously.24 One factor that partially explains why IA appears to be effective is risk screening. Women who give birth in settings that use IA routinely usually have a singleton, www.clinicalobgyn.com
term fetus in vertex presentation at the onset of spontaneous labor. This population has a very low a priori risk of developing fetal acidosis during labor. In addition, IA requires one-to-one care provided by a clinician who is familiar with IA guidelines and IA technique.25 Continuous labor support is also independently associated with better outcomes and lower cesarean birth rates.26 Finally, although IA does not reliably detect FHR variability, it does detect other signs of fetal compromise, such as tachycardia, bradycardia, and decelerations. Acute fetal hypoxia does not develop during labor if these FHR characteristics are absent,23 and IA when utilized appropriately should detect them in time to employ continuous monitoring and consultation when necessary. In summary, although the evidence for the safety and effectiveness of IA is indirect, this evidence is robust and consistent across several study designs.
Labor Support and Doula Care Before the mid-20th century, laboring women were attended and supported by other women during childbirth. As birth moved from the home to the hospital, the provision of continuous support during labor became much less common. In the absence of supportive care, however, women may be inadvertently subjected to institutional routines that eclipse important needs in labor, such as emotional support, comfort measures, and information. Although the presence of friends and family members in the labor room is common today, these individuals may not have the motivation or the skills to provide continuous labor support. EVIDENCE IN FAVOR OF LABOR SUPPORT
In a recent Cochrane review of 22 trials (n = 15,288) in hospitals in 16 countries, Hodnett et al26 found that women who received continuous support during labor were less likely to have a cesarean [relative risk (RR) = 0.78; 95% confidence interval
Preventing Primary Cesarean Births (CI), 0.67-0.91] than were women who did not. Moreover, women with continuous labor support were more likely to have a spontaneous vaginal birth (RR = 1.08; 95% CI, 1.04-1.12) and shorter labors [mean difference (MD) = 0.58 h; 95% CI, –0.85 to –0.31] and were less likely to have a baby with a low 5-minute Apgar score (fixed-effect; RR = 0.69; 95% CI, 0.500.95) than were women who received usual care.26 The persons providing support in these trials were members of the hospital staff (nurse, midwife, or student midwife), doulas or childbirth educators, or members of the woman’s social network. Subgroup analysis demonstrated, however, that women benefitted most when the support person was solely present to provide labor support, had training and/or experience, and was not a member of the woman’s family or social network.26 Hodnett27 and Hofmeyr et al28 described 2 theoretical explanations for the effectiveness of labor support. Although both theories posit that labor support increases women’s sense of being in control and being capable of navigating the labor process, one focuses on the hospital environment and the other focuses on the individual effects for the woman. Hofmeyr et al’s28 theory proposes that continuous companionship may serve as a buffer to the stressors of labor as well as to a harsh hospital environment. Hodnett27 expanded on this view by proposing that labor support affects 2 pathways: enhancement of the fetal passageway and a decreased stress response in the mother. In this model, labor support enhances the fetal passage by promoting mobility and the use of gravity, upright positions, and improved comfort of the mother. It may also reduce anxiety and fear, thereby decreasing the stress response and high levels of epinephrine in the blood. Thus, labor support may mitigate the ‘‘cascade of interventions’’ and lead to decreased use of analgesia and anesthesia, labor augmentation, continuous EFM, and other associated interventions.27
287
DOULA CARE
In recent years, the use of ‘‘doulas,’’ or lay women with special training in labor support, has increased gradually worldwide. In North America, an estimated 50,000 individuals have received doula training, and some hospitals sponsor doula services.29 National surveys in the United States reported that 3% to 5% of women have used doula services.18 Moreover, 5 of the 22 randomized trials reported in the Cochrane review specifically analyzed labor support provided by doulas.27 Although it appears that there may be some distinct advantages to doula support in labor, these services are frequently unavailable to lowincome women. Given the clear benefits of labor support, however, policy makers and hospital administrators should weigh the cost of implementation of a doula program against the cost of surgical birth and other obstetric interventions and consider including it as an essential service for all women.27
Upright Position and Free Mobility The majority of women in the United States spend much of their labor in bed. Although the disadvantages of supine positioning are well known, laboring in bed has become commonplace, largely as a consequence of modern interventions such as continuous EFM and epidural anesthesia. Radiographic studies of laboring women conducted in the 1960s found that upright positions increase room in the midpelvis and create approximately 20% more space in the pelvic outlet.30 Recent evidence from a 2013 Cochrane analysis revealed that women who remained upright and mobile during the first stage of labor had significantly shorter labors than did their recumbent counterparts (average MD = –1.36; 95% CI, – 2.22 to – 0.51; 15 studies, 2503 women; random effects, T2 = 2.39, w2 = 203.55, df = 14, P
Preventing Primary Cesarean Births: Midwifery Care KIM J. COX, PhD, CNM,* and TEKOA L. KING, MPH, CNMw *College of Nursing, University of New Mexico, Albuquerque, New Mexico; and w Health Sciences Clinical Professor, School of Nursing, University of California, San Francisco, California
Abstract: The incidence of cesarean birth in the United States is alarmingly high and cesareans are associated with added morbidities for women and newborns. Thus strategies to prevent cesarean particularly for low-risk, nulliparous women at term with a singleton fetus are needed. This article addresses evidence-based practices that may be used during intrapartum to avoid primary cesarean, including patience with progress in labor, intermittent auscultation, continuous labor support, upright positions, and free mobility. Second-stage labor practices, such delayed pushing and manual rotation of the fetus, are also reviewed. This package of midwifery-style care practices can potentially lower primary cesarean rates. Key words: cesarean birth, prevention, dystocia, intermittent auscultation, continuous labor support, mobility in labor
among US states, from 22.6% (Alaska) to 38.8% (New Jersey).2 Although cesarean birth can be life saving for a woman or her fetus, the sharp increase in cesarean rates over the past 2 decades was not accompanied by a decrease in either neonatal or maternal morbidity or mortality.3 Furthermore, the wide variation in cesarean rates among hospitals and states across the country for nulliparous women at term with a singleton vertex fetus (NTSV) at the onset of labor suggests that clinical practice patterns may play a role, particularly for common indications, such as dystocia and abnormal or indeterminate fetal heart rate (FHR) tracing.3 In response to this problem, the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) published a consensus statement in March 2014.3 The article raised the concern that primary cesarean has been overused and that efforts should be directed toward safely decreasing current rates. Two of the most common indications for which management may be modified include dystocia and abnormal or indeterminate
Introduction In 2013, one third (32.7%) of the 4 million women who gave birth in the United States had a cesarean section.1 Cesarean rates increased by 60% overall from 1996 to 2011, although rates varied widely Correspondence: Kim J. Cox, PhD, CNM, College of Nursing, University of New Mexico, MSC, Albuquerque, NM. E-mail: [email protected] The authors declare that they have nothing to disclose. CLINICAL OBSTETRICS AND GYNECOLOGY
282 | www.clinicalobgyn.com
/
VOLUME 58
/
NUMBER 2
/
JUNE 2015
Preventing Primary Cesarean Births FHR tracings.3 This article reviews the evidence regarding labor management practices that are associated with midwifery care and lower cesarean rates. We offer suggestions that may be helpful in reducing the primary cesarean rate in nulliparous women at term.
Background Considering the effect on future pregnancies, it is important to understand the drivers behind primary cesarean rates and attempt to reduce them. This is particularly important for low-risk NTSV women, as they are the cohort of women who should be the least likely to have a cesarean birth. Moreover, the primary cesarean rate is a key indicator of health care quality in this group.4 One important factor is the wide variation in cesarean rates from hospital to hospital and from state to state. In 2013, the primary cesarean rate was 21.5% nationally, with a low of 13% in Utah to a high of 27% in Florida and Louisiana.1 Because maternal characteristics, such as age, weight, and ethnicity, do not adequately account for the differences in rates,5 variations in practice, providers, and patient preferences are likely to play a role. Another factor is the indication for the cesarean birth. In population-based studies, >50% of primary cesareans were performed for dystocia or abnormal or indeterminate FHR tracing.6,7 Dystocia, the leading indication, is problematic for several reasons. Many hospitals and providers still use the Friedman Curve to assess labor progress. More recent research by the Consortium on Safe Labor, however, has demonstrated that labor progression is slower than what was previously thought.6,8 Contemporary labor practices, such as epidural anesthesia, induction, laboring in bed, and frequent use of oxytocin (Pitocin; JHP Pharmaceuticals, Parsippany, NJ) differ substantially from labor management in Friedman’s day.3 Furthermore, there are a number of evidence-based labor
283
practices that are already in use by midwives during first-stage and second-stage labor that could be helpful in decreasing the diagnosis of dystocia. These practices include patience with progress in the first stage of labor, intermittent auscultation (IA) for low-risk women, continuous labor support, doula care, and encouraging upright positions and free mobility throughout labor. Second-stage labor practices, such as extended duration of the second stage, delayed pushing, and manual rotation of the fetus, are also reviewed. The article concludes with an exploration of how a ‘‘package’’ of midwifery-style care practices can potentially influence primary cesarean rates.
Dystocia: 6 is the New 4 Dystocia is the leading cause of primary cesarean sections today, accounting for approximately half of those performed during labor.6 Dystocia also accounts for the greatest variation in institutional cesarean rates.4 In most labor and delivery settings, women’s labor progress is measured against the Friedman curve to determine normal progress and to diagnose dystocia or arrest of labor. The genesis of this curve is worth reviewing. Dr Emanuel Friedman identified the Friedman curve in the 1950s. He measured the progress of 500 primigravid women to determine the mean, median, range, and SD of the first stage of labor. He divided the calculated sigmoid curve into the latent, active, and transition phases ‘‘for purposes of mathematical simplification.’’9(p569) The Friedman curve is not a good template for women in labor today for several reasons. First, Friedman’s calculations were based on a cohort of women who were different from the population of women who give birth in the United States today. For example, women today are more likely to be obese and older, the racial and ethnic diversity is more robust, and labor practices that affect the duration of labor are different than they were 50 years ago.8,10–14 Second, the mathematical www.clinicalobgyn.com
284
Cox and King
TABLE 1.
Normal Labor Progress in Nulliparous Women at Term in Spontaneous Labor
References N 9
Friedman 500
Albers10
Key Findings
Clinical Implications
Mean active phase was 2.5 h
Care practices that independently affect labor length were used in the 1950s that are no longer part of normal intrapartum care; the Friedman curve should not be used to monitor labor progress Use of IA and ambulation during active labor in women without analgesia may shorten length of the first stage of labor
2511
Mean active phase duration was 7.7 h (17.5 h SD) Midwifery-managed care; 43.7% used EFM, 61% were ambulatory in labor; EFM and ambulation were associated with longer labors Zhang 1329 Mean duration of active phase was 5.5 h et al11 (95% 13.7 h) Marked inter-individual variability in cm at which active phase starts (3-5 cm) Time interval of no change >2 h not uncommon before 7 cm Neal 7009 Mean duration of active phase was 6 h et al12 (13.4 SD); systematic review included studies of women with analgesia and oxytocin augmentation; slowest normal rate of cervical dilation approximates 0.5-0.6 cm/h Laughton 27,471 Median duration of active phase: et al13 4-6 cm: 6.5 h (95% 24 h) 5-6 cm: 3.6 h (95% 15.1 h) 6-C/C: 1.2 h (95% 10 h) Neal 216 Comparison of women admitted in latent et al14 vs. active labor Median duration of active phase was 9.5 h in women admitted in latent phase and 5.8 h in women admitted in active labor Likelihood of cesarean section was higher in the women admitted in latent labor (OR = 2.6; 95% CI, 1.02-6.37)
Allow at least 2 h between each increment of cervical dilation before 7 cm
Allow at least 2 h between each increment of cervical dilation in late active phase of labor
Duration of active phase shortens when interval comparison between each degree of dilatation is compared Avoid admission or initiation of obstetric interventions for women who are in latent labor
C/C indicates completely effaced and completely dilated; CI, confidence interval; EFM, electronic fetal monitoring; IA, intermittent auscultation; OR, odds ratio.
averaging used to create the Friedman curve blunted some very important distinctions in how women progress from 1 cervical dilation to the next.8 Recently, Zhang and colleagues reanalyzed labor progress using data from the National Collaborative Perinatal Project. The National Collaborative Perinatal Project is a large prospective study of women who gave birth between 1955 and 1966, when intrapartum management was similar to the management experienced by the women in Friedman’s sample. Using a www.clinicalobgyn.com
repeated-measures analysis, Zhang et al8 found that the latent phase of labor lasted longer than Friedman detected and that a deceleration phase did not occur. Subsequently, several researchers have used contemporary data to examine labor progress in women who give birth today. Table 1 summarizes the results of recent studies on labor progress in nulliparous women at term.9–14 Table 2 presents a small sample of the current research on differences in labor progress for specific populations.15–17 In summary, use of the Friedman curve to
Preventing Primary Cesarean Births TABLE 2.
Labor Progress Duration in Subpopulations of Women
References Population
Albers et al15
Norman et al16
Zaki et al17
285
Key Findings
Clinical Implications
N = 1473 low-risk women at term Hispanic, nonwith and without analgesia and Hispanic white, labor interventions, cared for by and Native nurse-midwives American Length of active phase of labor was not different in Hispanic and American Indian women compared with non-Hispanic white women Length of second stage was significantly shorter in Native American women compared with non-Hispanic white women Increased BMI 5204 nulliparous and multiparous women; adjusted for parity, labor type, race, and birth weight Labor duration is longer in women with a BMI>30 (OR = 4.7 vs. 4.1 h, P40 have approximately 2 h longer first stage of labor compared with women with a BMI of r25 Maternal age maybe considered when assessing normal progress in the active phase of labor
BMI indicates body mass index; OR, odds ratio.
determine the limits of normal is resulting in overdiagnosis of dystocia when women are still in latent labor, which results in overutilization of cesarean section. Until an improved labor partogram is developed and validated for clinical use, the Friedman curve should be abandoned and the summary points highlighted in the accompanying tables used as benchmarks for managing women’s labor progress.
IA for FHR Monitoring Approximately 20% to 30% of all NTSV cesareans are performed for fetal intolerance of labor.4 Although 90% of women who give birth in the United States undergo
continuous electronic fetal heart rate monitoring (EFM),18 interpretation of variant FHR patterns has a high false-positive rate. Therefore, continuous EFM is a poor screening tool for identification of fetal acidemia. EFM was adopted into clinical practice in the 1960s, before the technology was evaluated for clinical utility. Subsequently, several randomized-controlled trials (RCTs) were conducted that compared EFM with IA, and the most recent Cochrane meta-analysis of this body of work has confirmed that EFM is associated with higher cesarean section rates compared with IA without improvement in Apgar scores, perinatal mortality, or rates of cerebral palsy.19 It is important to remember www.clinicalobgyn.com
286
Cox and King
that the Cochrane results did not show either EFM or IA to be superior for identification of fetal acidemia. Therefore, because EFM is associated with a higher cesarean section rate, it is of value in reassessing the effectiveness of IA. Ideally, the effectiveness of IA would be best determined by conducting an RCT that compared IA with no monitoring or IA with another form of fetal monitoring. However, it would be unethical to randomize women to no fetal monitoring during labor. RCTs are also unlikely to be performed because very large numbers of laboring women would need to participate to detect a real difference in perinatal mortality, and this magnitude of study is difficult to achieve. However, evidence that supports the use of IA is available. EFFECTIVENESS OF IA
IA is standard practice for monitoring the fetus during labor in free-standing birth centers. The maternal and newborn outcomes for women who give birth in these settings are exceptionally good overall, which provides some indirect evidence that IA is part of a process of care that provides effective screening for developing fetal acidemia.20,21 In addition, women who give birth in free-standing birth centers have lower cesarean section rates than do women who have a similar a priori risk for fetal acidemia and who give birth in hospital settings.22 Finally, 1 real critique of the RCTs comparing IA with EFM is that those studies are now more than 30 years old, when knowledge of the physiology of the FHR in labor was not as well known as it is today.23 A current, albeit small, study of IA used in a hospital setting showed that the women who received IA had a lower incidence of cesarean birth than did women who were monitored continuously.24 One factor that partially explains why IA appears to be effective is risk screening. Women who give birth in settings that use IA routinely usually have a singleton, www.clinicalobgyn.com
term fetus in vertex presentation at the onset of spontaneous labor. This population has a very low a priori risk of developing fetal acidosis during labor. In addition, IA requires one-to-one care provided by a clinician who is familiar with IA guidelines and IA technique.25 Continuous labor support is also independently associated with better outcomes and lower cesarean birth rates.26 Finally, although IA does not reliably detect FHR variability, it does detect other signs of fetal compromise, such as tachycardia, bradycardia, and decelerations. Acute fetal hypoxia does not develop during labor if these FHR characteristics are absent,23 and IA when utilized appropriately should detect them in time to employ continuous monitoring and consultation when necessary. In summary, although the evidence for the safety and effectiveness of IA is indirect, this evidence is robust and consistent across several study designs.
Labor Support and Doula Care Before the mid-20th century, laboring women were attended and supported by other women during childbirth. As birth moved from the home to the hospital, the provision of continuous support during labor became much less common. In the absence of supportive care, however, women may be inadvertently subjected to institutional routines that eclipse important needs in labor, such as emotional support, comfort measures, and information. Although the presence of friends and family members in the labor room is common today, these individuals may not have the motivation or the skills to provide continuous labor support. EVIDENCE IN FAVOR OF LABOR SUPPORT
In a recent Cochrane review of 22 trials (n = 15,288) in hospitals in 16 countries, Hodnett et al26 found that women who received continuous support during labor were less likely to have a cesarean [relative risk (RR) = 0.78; 95% confidence interval
Preventing Primary Cesarean Births (CI), 0.67-0.91] than were women who did not. Moreover, women with continuous labor support were more likely to have a spontaneous vaginal birth (RR = 1.08; 95% CI, 1.04-1.12) and shorter labors [mean difference (MD) = 0.58 h; 95% CI, –0.85 to –0.31] and were less likely to have a baby with a low 5-minute Apgar score (fixed-effect; RR = 0.69; 95% CI, 0.500.95) than were women who received usual care.26 The persons providing support in these trials were members of the hospital staff (nurse, midwife, or student midwife), doulas or childbirth educators, or members of the woman’s social network. Subgroup analysis demonstrated, however, that women benefitted most when the support person was solely present to provide labor support, had training and/or experience, and was not a member of the woman’s family or social network.26 Hodnett27 and Hofmeyr et al28 described 2 theoretical explanations for the effectiveness of labor support. Although both theories posit that labor support increases women’s sense of being in control and being capable of navigating the labor process, one focuses on the hospital environment and the other focuses on the individual effects for the woman. Hofmeyr et al’s28 theory proposes that continuous companionship may serve as a buffer to the stressors of labor as well as to a harsh hospital environment. Hodnett27 expanded on this view by proposing that labor support affects 2 pathways: enhancement of the fetal passageway and a decreased stress response in the mother. In this model, labor support enhances the fetal passage by promoting mobility and the use of gravity, upright positions, and improved comfort of the mother. It may also reduce anxiety and fear, thereby decreasing the stress response and high levels of epinephrine in the blood. Thus, labor support may mitigate the ‘‘cascade of interventions’’ and lead to decreased use of analgesia and anesthesia, labor augmentation, continuous EFM, and other associated interventions.27
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DOULA CARE
In recent years, the use of ‘‘doulas,’’ or lay women with special training in labor support, has increased gradually worldwide. In North America, an estimated 50,000 individuals have received doula training, and some hospitals sponsor doula services.29 National surveys in the United States reported that 3% to 5% of women have used doula services.18 Moreover, 5 of the 22 randomized trials reported in the Cochrane review specifically analyzed labor support provided by doulas.27 Although it appears that there may be some distinct advantages to doula support in labor, these services are frequently unavailable to lowincome women. Given the clear benefits of labor support, however, policy makers and hospital administrators should weigh the cost of implementation of a doula program against the cost of surgical birth and other obstetric interventions and consider including it as an essential service for all women.27
Upright Position and Free Mobility The majority of women in the United States spend much of their labor in bed. Although the disadvantages of supine positioning are well known, laboring in bed has become commonplace, largely as a consequence of modern interventions such as continuous EFM and epidural anesthesia. Radiographic studies of laboring women conducted in the 1960s found that upright positions increase room in the midpelvis and create approximately 20% more space in the pelvic outlet.30 Recent evidence from a 2013 Cochrane analysis revealed that women who remained upright and mobile during the first stage of labor had significantly shorter labors than did their recumbent counterparts (average MD = –1.36; 95% CI, – 2.22 to – 0.51; 15 studies, 2503 women; random effects, T2 = 2.39, w2 = 203.55, df = 14, P
