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Prolonged Labor & Potential Risk Factors
cost-effective and safe alternative to current labor-induction protocols.
• • • Commentary: The use of misoprostol (Cytotec; Searle Canada, Oakville, Ontario, Canada), an inexpensive synthetic PGE 1 analogue currently marketed as an oral tablet with two formulations (100 /-Lg or 200 /-Lg), is being evaluated in multiple centers. The successful vaginal deliveries and time to delivery reported in this study, which used 50 JLg every 4 hours, are reassuring. The incidence of cesarean section was equal in both groups. The authors did not find an increased incidence in hyperstirnulation or nonreassuring fetal heart patterns associated with the use of rnisoprostol, This study supports the use of vaginal misoprostol as an effective method of labor induction. It is no less safe and is many times less expensive than currently approved prostaglandin agents.
Evaluation of the Cesarean Birth Epidemic Porreco RP, Thorp JA. The cesarean birth epidemic: Trends, causes, and solutions. Am] ObstetGynecoI1996:175:369-74.
Synopsis: The authors reviewed the change of cesarean section rate over the last 25 years of obstetric practice. They note that the cesarean section rate peaked in 1988, with total and primary cesarean rates of 24.7% and 17.5%, respectively. By 1993, the total cesarean section rate was 22.8% and the primary rate was 16.3%, a general decrease from previous years. The indications as statistically evaluated in 1991 included dystocia (30.4%), breech presentation (11.7%), and fetal distress (9.2%). The authors identified their socioeconomic concern regarding medical/legal burden, health care economics including reimbursement practices, and change in consumer awareness and expectations. Their proposed solutions stress encouragement of a trial of vaginal birth after cesarean, active management of labor, limited use of conduc©1997 by the American College of Obstetricians andGvnecolooists Published by Elsevier SCience Inc. 1085·6862'97'$4 50'
tion anesthesia, labor induction, and cervical ripening preparations, and a potpourri of alternative management strategies including organized inhouse attending coverage and global obstetric reimbursement.
• • • Commentary: The authors' overall evaluation of cesarean section rate changes is enlightening and points out that the incidence of breech presentation and fetal distress are small components of the cesarean rate. Their focus on reducing repeat cesarean sections and cesareans done for dystocia, especially latent phase deliveries, is to be encouraged. It is doubtful whether reimbursement modifications will have a significant impact on cesarean section practices by the obstetrician/gynecologist. Although alternative practices of hydrotherapy, massage, and ambulation may help patients to relax and improve their satisfaction,they may not affectcesarean section rates.
Shared Care vs Midwifery-Managed Care Turnbull D, Holmes A, Shields N, Cheyne H, Twaddle S, Gilmour WH, er al. Randomised, controlled trial of efficacy of midwife-managedcare. Lancet 1996;348:213-8.
Synopsis: A randomized, controlled trial of1299 pregnant women who, at initial screening, had no high-risk factors identified. Of these women, 648 were assigned to midwife-managed care and 651 to physician and midwife (shared) care. Approximately 33% of the women were transferred from midwife-managed care to shared care, 28.7% for clinical reasons and 3.7% for nonclinical reasons. The authors reported that women in the midwifemanaged care group were less likely than women in shared care to have induction of labor (23.9% versus 33.3%). Patient satisfaction in both patient groups was high, with the mean patient satisfaction score slightly higher in the midwifery group than in the shared care group.
• • •
Commentary: Sixty percent of patients in this study were in the two least affluent demographic groups evaluated. The interplay of expectations and outcome satisfaction needs to be considered. Additionally, approximately a third of the midwifery patients required transfer to the physician-midwifery shared care group during the course of their prenatal care. A major component of the reduction in midwifery group inductions was the lack of induction at 42 weeks' gestation and above. The midwifery practice used fewer antenatal visits than the shared care practice, an average of one fewer visit per patient. The concept of collaborative practice between nurse-midwives and o bstetrician/gynecologists has been demonstrated to provide quality care and patient satisfaction. Obstetric care without physician interaction and collaboration, even in low-risk groups, may require a high number of patient transfers.
Prolonsed Labor & Potential Risk Factors Malone FD, Geary M, Chelmow D, Strange
J, Boylan P, D' Alton ME. Prolonged labor in
nulliparas: Lessons from the active management of labor. Obstet Gynecol 1996;88: 211-5.
Synopsis: For the 5-year period of 1990-1994,9018 nulliparas delivering at the National Maternity Hospital in Dublin met inclusion criteria for the study. Of these, 147 (1.6%) had prolonged labor> 12 hours, a singleton gestation, cephalic presentation, and labor occurring at >37 weeks' gestation. Each of the 147 patients were matched with the next nulliparous patient who delivered with labor <12 hours and fulfilledthe inclusion criteria. Prolonged labor was due to insufficient uterine action in 65%, persistent occipitoposterior position in 24%, and cephalopelvic disproportion in 11% of cases. Multivariate analysis showed cervical dilatation <2 em on admission, early epidural placement, epidural placement at 2:2 em, and birth weight >4000 g to be significant independent predictors (odds ratios 3.1, 42.7,5.1, and 10.2, respectively). Maternal weight and body mass index already have been implicated in the etiology of abnormal labor, with
[anuarv/Fehruarv 1997 • ACOG CUNICAL REVIEW. 3
an increased requirement for oxytocin augmentation and increased primary cesarean delivery rate noted in obese patients. These factors, as stated by the authors, cannot be influenced once the patient has been admitted in labor.
• • • Commentary: Fetal macrosomia and cervical dilatation of <2 cm on admission to the labor and delivery unit are easily understood variables and causes of prolonged labor in nulliparas. The role of epidural anesthesia remains circumspect. Conduction anesthesia used early in latent phase labor has long been thought to slow the patient's progress. Whether this is related to the epidural alone, the timing of its placement, or perhaps the dose or type of agent used is unclear. Because the National Maternity Hospital did not use mid-pelvic rotations, 50% of the cesarean section rates in this group belong to persistent occipitoposterior positions. This study is helpful in identifying patient variables that may be prospective risk factors for lengthening labor in nulliparas.
Office-Based Obstetric Screening Tests Wilkins-Haug L, Horton JA, Cruess DF, Frigoletro FD. Antepartum screening in the office-based practice: Findings from the collaborative ambulatory research network. Obstet Gynecol1996;88:483-9.
Synopsis: The Collaborative Ambulatory Research Network, a voluntary subset of 550 ACOG Fellows from 130 practices, responded to a selfadministered study regarding hepatitis B, gestational diabetes, neural tube defects, and trisomy 21 office screening techniques. Hepatitis screening was performed by all practices reporting, with 95% of patients being tested; however, only 55% (six of 11) of newborns at risk received treatment. O'Sullivan screening (50-g glucose load with a I-hour postload glu-
cose) was performed for all obstetric patients by 94% of the practices, regardless of risk factors. Two-thirds of these practices used:::::: 140 mg/ dL for further screening, and 34% used glucose levels in the 130-135 mg/dL range. Ninety-two percent of respondents report offering maternal serum a-fetoprotein screening for neural' tube defects. Eighty-four percent of respondents offered serum screening for trisomy 21 to women <35 years of age, with 68% using a double- or triplescreen technique. Women ::::::35 years of age had serum screening offered by 87% of the practices; however, 41 % offered serum screening only if amniocentesis was declined when offered for age risk alone. Practitioner appreciation of the relatively high initial positive rate and poor specificity of serum screening was underappreciated by a large number of respondents.
• • • Commentary: The Collaborative Ambulatory Research Network provides the College access to practitioners' ongoing clinical practice style. In 1990, ACOG was awarded a grant from the Department of Health and Human Services Bureau of Maternal and Child Health to establish the Collaborative Ambulatory Research Network. Through this method, practicestyle data are gathered. This article reviews obstetric screening tests and their use and interpretation by this group of motivated practitioners. The finding of high levels of use is not surprising. The underappreciation of falsepositive rates and triple screening for Down syndrome provides an opportunity for continuing education. While the O'Sullivan diabetic screening test is undergoing reassessment for its clinical benefit, this study shows use by this group of practitioners to have expanded beyond ACOG guidelines for 50-g glucose load with l-hour glucose for all pregnant patients ::::::30 years of age or for younger women with a risk factor.
4 • ACOG CLINICAL REVIEW. Ianuarv/Februarv 1997
The Collaborative Ambulatory Research Network enables ACOG to access practice patterns continually and to provide educational feedback to its membership.
Blood Pressure Patterns in Pregnancy Benedetto C, Zonca M, Marozio L, Dolci C, Carandente F, Massobrio M. Blood pressure patterns in normal pregnancy and in pregnancy-induced hypertension, preeclampsia, and chronic hypertension. Obstet Gynecol 1996;88:503-10.
Synopsis: The authors studied four groups ofwomen with singleton pregnancies (73 controls, 48 patients with pregnancy-induced hypertension, 38 patients with preeclampsia, and 53 patients with mild to moderate chronic hypertension). These patients were admitted between 8 and 16 weeks', 20 and 25 weeks', 28 and 35 weeks', and 36 and 40 weeks' gestation for continuous, hypertensive evaluation for a 24-hour period, essentially at bedrest. The pregnancy-induced hypertension and preeclamptic patients were studied from the time of their hypertensive diagnosis. The control patients established a normal diurnal variation chronogram, documenting both systolic and diastolic blood pressure variations. Highest levels (acrophase) occurred between 1:00 and 3:00 PM. There was a consistent lowering of both systolic and diastolic pressures in the evening hours. In pregnancy-induced hypertension, especially in preeclampsia, besides the obvious increase in blood pressure, the circadian blood pressure occilations were less pronounced and the acrophase shifted into the late afternoon. The authors speculate that the acrophase shift probably is dependent on both the severity of the hypertension and the etiology of preeclampsia.
• • • Commentary: This exhaustive study, which included> 19,000 blood pres:91997 by the Amencan COllege 01 Obstetnctans and Gynecologists Published bv Hsever SCience Inc 1085-6862.197/$450
• • • Commentary: The use of misoprostol (Cytotec; Searle Canada, Oakville, Ontario, Canada), an inexpensive synthetic PGE 1 analogue currently marketed as an oral tablet with two formulations (100 /-Lg or 200 /-Lg), is being evaluated in multiple centers. The successful vaginal deliveries and time to delivery reported in this study, which used 50 JLg every 4 hours, are reassuring. The incidence of cesarean section was equal in both groups. The authors did not find an increased incidence in hyperstirnulation or nonreassuring fetal heart patterns associated with the use of rnisoprostol, This study supports the use of vaginal misoprostol as an effective method of labor induction. It is no less safe and is many times less expensive than currently approved prostaglandin agents.
Evaluation of the Cesarean Birth Epidemic Porreco RP, Thorp JA. The cesarean birth epidemic: Trends, causes, and solutions. Am] ObstetGynecoI1996:175:369-74.
Synopsis: The authors reviewed the change of cesarean section rate over the last 25 years of obstetric practice. They note that the cesarean section rate peaked in 1988, with total and primary cesarean rates of 24.7% and 17.5%, respectively. By 1993, the total cesarean section rate was 22.8% and the primary rate was 16.3%, a general decrease from previous years. The indications as statistically evaluated in 1991 included dystocia (30.4%), breech presentation (11.7%), and fetal distress (9.2%). The authors identified their socioeconomic concern regarding medical/legal burden, health care economics including reimbursement practices, and change in consumer awareness and expectations. Their proposed solutions stress encouragement of a trial of vaginal birth after cesarean, active management of labor, limited use of conduc©1997 by the American College of Obstetricians andGvnecolooists Published by Elsevier SCience Inc. 1085·6862'97'$4 50'
tion anesthesia, labor induction, and cervical ripening preparations, and a potpourri of alternative management strategies including organized inhouse attending coverage and global obstetric reimbursement.
• • • Commentary: The authors' overall evaluation of cesarean section rate changes is enlightening and points out that the incidence of breech presentation and fetal distress are small components of the cesarean rate. Their focus on reducing repeat cesarean sections and cesareans done for dystocia, especially latent phase deliveries, is to be encouraged. It is doubtful whether reimbursement modifications will have a significant impact on cesarean section practices by the obstetrician/gynecologist. Although alternative practices of hydrotherapy, massage, and ambulation may help patients to relax and improve their satisfaction,they may not affectcesarean section rates.
Shared Care vs Midwifery-Managed Care Turnbull D, Holmes A, Shields N, Cheyne H, Twaddle S, Gilmour WH, er al. Randomised, controlled trial of efficacy of midwife-managedcare. Lancet 1996;348:213-8.
Synopsis: A randomized, controlled trial of1299 pregnant women who, at initial screening, had no high-risk factors identified. Of these women, 648 were assigned to midwife-managed care and 651 to physician and midwife (shared) care. Approximately 33% of the women were transferred from midwife-managed care to shared care, 28.7% for clinical reasons and 3.7% for nonclinical reasons. The authors reported that women in the midwifemanaged care group were less likely than women in shared care to have induction of labor (23.9% versus 33.3%). Patient satisfaction in both patient groups was high, with the mean patient satisfaction score slightly higher in the midwifery group than in the shared care group.
• • •
Commentary: Sixty percent of patients in this study were in the two least affluent demographic groups evaluated. The interplay of expectations and outcome satisfaction needs to be considered. Additionally, approximately a third of the midwifery patients required transfer to the physician-midwifery shared care group during the course of their prenatal care. A major component of the reduction in midwifery group inductions was the lack of induction at 42 weeks' gestation and above. The midwifery practice used fewer antenatal visits than the shared care practice, an average of one fewer visit per patient. The concept of collaborative practice between nurse-midwives and o bstetrician/gynecologists has been demonstrated to provide quality care and patient satisfaction. Obstetric care without physician interaction and collaboration, even in low-risk groups, may require a high number of patient transfers.
Prolonsed Labor & Potential Risk Factors Malone FD, Geary M, Chelmow D, Strange
J, Boylan P, D' Alton ME. Prolonged labor in
nulliparas: Lessons from the active management of labor. Obstet Gynecol 1996;88: 211-5.
Synopsis: For the 5-year period of 1990-1994,9018 nulliparas delivering at the National Maternity Hospital in Dublin met inclusion criteria for the study. Of these, 147 (1.6%) had prolonged labor> 12 hours, a singleton gestation, cephalic presentation, and labor occurring at >37 weeks' gestation. Each of the 147 patients were matched with the next nulliparous patient who delivered with labor <12 hours and fulfilledthe inclusion criteria. Prolonged labor was due to insufficient uterine action in 65%, persistent occipitoposterior position in 24%, and cephalopelvic disproportion in 11% of cases. Multivariate analysis showed cervical dilatation <2 em on admission, early epidural placement, epidural placement at 2:2 em, and birth weight >4000 g to be significant independent predictors (odds ratios 3.1, 42.7,5.1, and 10.2, respectively). Maternal weight and body mass index already have been implicated in the etiology of abnormal labor, with
[anuarv/Fehruarv 1997 • ACOG CUNICAL REVIEW. 3
an increased requirement for oxytocin augmentation and increased primary cesarean delivery rate noted in obese patients. These factors, as stated by the authors, cannot be influenced once the patient has been admitted in labor.
• • • Commentary: Fetal macrosomia and cervical dilatation of <2 cm on admission to the labor and delivery unit are easily understood variables and causes of prolonged labor in nulliparas. The role of epidural anesthesia remains circumspect. Conduction anesthesia used early in latent phase labor has long been thought to slow the patient's progress. Whether this is related to the epidural alone, the timing of its placement, or perhaps the dose or type of agent used is unclear. Because the National Maternity Hospital did not use mid-pelvic rotations, 50% of the cesarean section rates in this group belong to persistent occipitoposterior positions. This study is helpful in identifying patient variables that may be prospective risk factors for lengthening labor in nulliparas.
Office-Based Obstetric Screening Tests Wilkins-Haug L, Horton JA, Cruess DF, Frigoletro FD. Antepartum screening in the office-based practice: Findings from the collaborative ambulatory research network. Obstet Gynecol1996;88:483-9.
Synopsis: The Collaborative Ambulatory Research Network, a voluntary subset of 550 ACOG Fellows from 130 practices, responded to a selfadministered study regarding hepatitis B, gestational diabetes, neural tube defects, and trisomy 21 office screening techniques. Hepatitis screening was performed by all practices reporting, with 95% of patients being tested; however, only 55% (six of 11) of newborns at risk received treatment. O'Sullivan screening (50-g glucose load with a I-hour postload glu-
cose) was performed for all obstetric patients by 94% of the practices, regardless of risk factors. Two-thirds of these practices used:::::: 140 mg/ dL for further screening, and 34% used glucose levels in the 130-135 mg/dL range. Ninety-two percent of respondents report offering maternal serum a-fetoprotein screening for neural' tube defects. Eighty-four percent of respondents offered serum screening for trisomy 21 to women <35 years of age, with 68% using a double- or triplescreen technique. Women ::::::35 years of age had serum screening offered by 87% of the practices; however, 41 % offered serum screening only if amniocentesis was declined when offered for age risk alone. Practitioner appreciation of the relatively high initial positive rate and poor specificity of serum screening was underappreciated by a large number of respondents.
• • • Commentary: The Collaborative Ambulatory Research Network provides the College access to practitioners' ongoing clinical practice style. In 1990, ACOG was awarded a grant from the Department of Health and Human Services Bureau of Maternal and Child Health to establish the Collaborative Ambulatory Research Network. Through this method, practicestyle data are gathered. This article reviews obstetric screening tests and their use and interpretation by this group of motivated practitioners. The finding of high levels of use is not surprising. The underappreciation of falsepositive rates and triple screening for Down syndrome provides an opportunity for continuing education. While the O'Sullivan diabetic screening test is undergoing reassessment for its clinical benefit, this study shows use by this group of practitioners to have expanded beyond ACOG guidelines for 50-g glucose load with l-hour glucose for all pregnant patients ::::::30 years of age or for younger women with a risk factor.
4 • ACOG CLINICAL REVIEW. Ianuarv/Februarv 1997
The Collaborative Ambulatory Research Network enables ACOG to access practice patterns continually and to provide educational feedback to its membership.
Blood Pressure Patterns in Pregnancy Benedetto C, Zonca M, Marozio L, Dolci C, Carandente F, Massobrio M. Blood pressure patterns in normal pregnancy and in pregnancy-induced hypertension, preeclampsia, and chronic hypertension. Obstet Gynecol 1996;88:503-10.
Synopsis: The authors studied four groups ofwomen with singleton pregnancies (73 controls, 48 patients with pregnancy-induced hypertension, 38 patients with preeclampsia, and 53 patients with mild to moderate chronic hypertension). These patients were admitted between 8 and 16 weeks', 20 and 25 weeks', 28 and 35 weeks', and 36 and 40 weeks' gestation for continuous, hypertensive evaluation for a 24-hour period, essentially at bedrest. The pregnancy-induced hypertension and preeclamptic patients were studied from the time of their hypertensive diagnosis. The control patients established a normal diurnal variation chronogram, documenting both systolic and diastolic blood pressure variations. Highest levels (acrophase) occurred between 1:00 and 3:00 PM. There was a consistent lowering of both systolic and diastolic pressures in the evening hours. In pregnancy-induced hypertension, especially in preeclampsia, besides the obvious increase in blood pressure, the circadian blood pressure occilations were less pronounced and the acrophase shifted into the late afternoon. The authors speculate that the acrophase shift probably is dependent on both the severity of the hypertension and the etiology of preeclampsia.
• • • Commentary: This exhaustive study, which included> 19,000 blood pres:91997 by the Amencan COllege 01 Obstetnctans and Gynecologists Published bv Hsever SCience Inc 1085-6862.197/$450