active management of labor: does it make a difference?
TRANSCRIPT
Active management of labor: Does it make a difference?
Rebecca Rogers, MD, * George J. Gilson, MD, ~ Anthony C. Miller, MD, b Luis E. Izquierdo, MD,"
Luis B. Curet, MD," and Clifford R. Quails, PhD ~
Albuquerqz~e, New Mexico
OBJECTIVE: Our goal was to evaluate whether active management of labor lowers cesarean section rates, shortens the length of labor, and overcomes any negative effects of epidural analgesia on nulliparous labor. STUDY DESIGN: We randomly assigned 405 low-risk term nulliparous patients to either an active management of labor (n = 200) or our usual care control protocol (n = 205). Patients who were undergoing active management of labor were diagnosed as being in labor on the basis of having painful palpable contractions accompanied by 80% cervical effacement, underwent early amniotomy, and were treated with high-dose oxytocin for failure to progress adequately in labor. RESULTS: The cesarean section rate in the active management of labor group was lower than that of controls but not significantly so (active management, 7.5%; controls, 11,7%; p = 0.36). The length of labor in the active management group was shortened by 1,7 hours (from 11.4 to 9.7 hours, p = 0.001). Fifty-five percent of patients received epidural analgesics; a reduction in length of labor persisted despite the use of epidural analgesics (active management 11.2 hours vs control 13.3 hours, p = 0.001). A significantly greater proportion of active management patients were delivered by 12 hours compared with controls (75% vs 58%, p = 0.01); this difference also persisted despite the use of epidural analgesics (66% vs 51%, p = 0.03). CONCLUSIONS: Patients undergoing active management had shortened labors and were more likely to be delivered within 12 hours, differences that pe{sisted despite the use of epidural analgesics. There was a trend toward a reduced rate of cesarean section. (Am J Obstet Gynecol 1997;177:599-605.)
Key words: Active management of labor, cesarean section
During the past 20 years of obstetric practice in the
United States there has been an alarming increase in the
rate of cesarean deliveries. The 1970 cesarean section rate
in the United States of 5.5% more than quadrupled over
the last two decades without an appreciable change in the
perinatal mortality rate. 1 The majority of this increase has
been in the number of cesarean sections performed on
nulliparous patients for dystocia and as repeat cesarean
sections in multiparous women. Any intervention aimed at reducing the first indication would, by definition, lead to a
reduction in the second. With the assumption that ineN-
cient uterine action is largely responsible tbr dystocia, augmentation of labor is an appropriate intervention. Ac-
tive management of labor, introduced in Ireland by
O'Driscoll et aI., 2 is associated with a low rate of abdominal
From the Division of Maternal-Fetal Medicine, Department of Obstetr&s and Gynecology, ~ the Department of Anesthesiology and Critical Care Medicine/' and the Department of Mathematics, ~ University of New Mexico Health Sciences Center. Supported in part by National Center for Research Resources-General Clinical Research Center grant 3 MO1-RRO0997 from the National Institutes of Health. Received for publication October 14, 1996," revised April 1, 1997; accepted April 16, 1997. Reprint requests: George J. Gilson, MD, 221l Lomaa NE, 4-ACC, Albuquerque, NM 87131. Copyright © 1997 by Mosby-Year Book, hze. 0002-9378/97 $5.00 + 0 6/1/82779
delivery in low-risk nulliparous patients. Unlike the use of
low-dose oxytocin proposed by Seitchik and Castillo ~ and
recommended by The American College of Obstetricians
and Gynecologists, 4 active management of labor uses a
relatively high dose of oxTtocin and also espouses the use of
early amniotomy once the diagnosis of labor is established. These interventions have been shown not to compromise
neonatal outcome, 5 while maintaining the cesarean section
rate at a much lower level than at comparable institutions in this country. 6
Prospective randomized contro]led investigations of
the efficacy of active management of labor in the United States 7, s demonstrate reductions in the lengths
of labor and a trend toward a reduct ion in cesarean
section rates in patients undergoing active manage-
ment compared with patients in usual care protocols.
We designed a prospective randomized trim to evalu-
ate the efficacy of early amniotomy and of high-dose
oxytocin in lowering cesarean section rates in nutlipa-
rous women in a university hospital setting. Our populat ion 's high epidural use reflects the analgesia preferences of many laboring patients in this country,
We evaluated whether active management of labor would shorten labor, lower cesarean section rates, and
overcome any negative effects epidural analgesia might have on labor in null iparous women.
599
600 Fto9ers et al. September 1997 Am J Obstet Gynecol
Material and methods
This randomized prospective study was carried out at
the University of New Mexico Hospital, a tertiary care
facility that serves a largely indigent population of His-
panic, white, and Native American patients. The smdy
period extended from August 1992 to April 1996. Eligi-
ble patients included nulliparous women at term preg- nancy who were examined in the antenatal testing unit
and who had painful, palpable uterine contractions <--5
minutes apart , with cervical effacement of at least 80%.
After informed consent was obtained, sealed opaque
envelopes with the patient's randomization to either the
active management of labor group or our current proto-
col were opened in the antepartum testing unit. Ran-
domization was based on a computer-generated list of
random numbers. Inclusion criteria included gestational
age ->37 weeks, cephalic presentation, no known mater-
nal medical complications, and no known fetal anoma-
lies. Patients were excluded if they had placenta previa or
abruptio placentae, twin gestations, prior uterine sur-
gery, or any other obstetric or any medical complication
of pregnancy. Resident physicians in training, under the
direct supervision of the authors, provided care to all
patients in both arms of the study. The active management of labor protocol was based
on a stritt diagnosis of labor, defined as the presence of
regular painful uterine contractions occurring every 2 to
5 minutes in a patient having attained at least 80%
cervical effacement, regardless of cervical dilatation. The
onset of labor, starting the clock on length of labor, was
established when the diagnosis of true labor was made. Amniotomy was performed within 2 hours of admission,
and augmentation of labor with oxytocin was instituted if
cervical dilatation of 1 cm/h r in the first stage of labor or
descent of 1 cm/h r in the second stage failed to occur.
Cervical examinations every 2 hours documented labor
progression. If augmentation was necessary, oxytocin
infusions were started at 6 m U / m i n and increased every
15 minutes, titrating to seven contractions in 15 minutes
or appropriate cervical change. The maximum dose of
oxytocin was 36 mU/min . Internal uterine pressure transducers were used as clinically indicated. Electronic
fetal heart rate monitoring, external or internal, was routinely used. One labor and delivery nurse was as-
signed to two laboring patients at any one time. The control protocol consisted of admission to the
labor suite at 3 to 4 cm of cervical dilatation, regardless of
effacement, in conjunction with regular painful contrac- üons every 2 to 5 minutes. If adequate progression in labor was not made, defined as cervical ehange of 1.25
cm/h r once the patient was in the active phase of labor, an oxytocin infusion was begun at 1 m U / m i n and was increased by 1 m U / m i n every 30 to 40 minutes to achieve and maintain adequate uterine activity as defined here. The decision to rupture membranes was made at the
discretion of the attending physician. The maximal dose
of oxytocin and the indications for the use of internal
uterine monitoring or electronic fetal heart rate moni-
toring, as weil as the nurse-to-patient ratio, were identical
to those in the investigational arm. Dystocia was defined as failure to progress in labor
either because of arrest of dilatation in the first stage of
labor or because of arrest of descent in the second stage of labor. M1 patients who were assigned the diagnosis of
dystocia attained at least 5 cm of cervical dilatation. Fetal intolerante of labor was defined as either repetitive late
decelerations or repetitive severe variable decelerations
of the fetal heart rate (defined as decelerations lasting
>60 seconds, dropping >60 beats /min below the base-
line heart rate or dropping below a rate of 60 beats/min)
or >5 minutes of bradycardia. A diagnosis of fetal
intolerance of labor was made only after attempts at
correction of the fetal heart rate pattern with hydration, uterine displaeement, oxygen administration, and ephe-
drine administration if indicated for epidural-associated maternal hypotension had failed. Fetal scalp pH deter-
minations were used in 10.3% of cases to confirm the
diagnosis of fetal intolerance of labor suggested by the tracings. Meconium staining of the amniotic fluid at the
time of membrane rupture was subjectively quantified by
the attendant as either thick or thin. Uterine hyperstimu-
lation was defined as the occurrence of uterine contrac-
tions every <-1 minute or of >2 minutes' duration. Epidural analgesics were administered at the. discre-
tion of the attending obstetrician and attending anesthe-
siologist on the request of the patient. Parturients re-
ceived continuous infusions of 0.08% bupivacaine plus 1 p~g/ml fentanyl after an initial bolus of 0.125% bupiva- caine plus 50 Ixg fentanyl. Infusions were titrated to
maintain a T8-10 sensory level. Epidural analgesia was continued throughout the second stage of labor until
delivery. The study was approved by the University of New
Mexico Hospital Human Research Review Committee
before its commencement. Statistical analysis was carried
out with independent t tests for the continuous variables and X 2 analysis for the frequency data. Fisher's exact test
was used where the cell size was small. Bivariate analysis of variance was also used where appropriate to compare
subgroups. Significance was set at a p value of <0.05. A power smdy indicated that 390 patients would be neces- sary to demonstrate with 80% power a reduction of the cesarean section rate from 14.5% in our institution in the
year before the study to the 5.5% rate reported by
O'Driscoll et al. 2
Results Between August 1992 and April 1996, 407 women were
enrolled in the study. Two women, both multiparous, were not included in the final analysis because they were
Volume 177, Number 3 Rogers e t al. 601 Am J Obstet GynecoI
Table I. Patient demographics
Characteristic Active management (n = 200) [ Control (n = 205) [ Sigrfifican«e
Age (}T) 20.7 -+ 4.2 20.5 + 3.7 NS Gestation (wk) 39.4 ± 1.0 39.6 ± 1.0 NS Ethnicity (%) NS Hispanic (No.) 132 (66%) 140 (68%) Non-Hispanic wbite (No.) 58 (29%) 51 (25%) Other (No.) 10 (5%) 14 (7%)
Table II. Labor characteristics
l ' Active management (n = 200) Control (n = 205) ] Significance
Augmentation (No.) Oxytocin dose (mU/min) AdmissiorJ dilatation (cm) Admission effacement (%) Spontaneous rupture of membranes (No.) Thick meconium (No.) Epidural analgesia (No.) Internal fetal monitors (No.)
112 (56%) t05 (51%) NS 13 ± 9 6 ± 5 p = o.ool
2.8 - 1.0 2.9 ± 1.I NS 90 (80oi00) 90 (80-100) NS 28 (14%) 41 (20%) NS 20 (10%) 16 (8%) NS
118 (59%) 105 (51%) NS 138 (69%) 137 (67%) NS
Table III. Length of labor (hours)
All patients Patients with epidural analgesia
Active management ] (n = 200) Controls (n = 205) Signißca~zce
Active management (n = 1 2 6 ) Cont~~ls (n = 131) Significance
Total length of labor (hr) 9.7 -+ 4.9 11.4 + 5.4 p = 0.002 11.2 + 4.6 13.3 + 5,2 p < 0.001 First stage 8.5 -+ 4.5 10.1 ± 5,9 p = 0.001 9.7 _+ 4.4 11.7 ± 4.8 p < 0.00I Second stage 1.0 -+ 1.0 1.1 ± 1ù4 NS 1.3 + 1.0 1.4 + 1.7 NS Third stage 0.15 ± 0.13 0.14 ± 0.13 NS 0.14 ± 0.13 0.14 ± 0.14 NS
en te red into the study in error. The results r epor t ed hefe
include 200 women in the active m a n a g e m e n t o f labor
arm and 205 in the cur ren t pro tocol control arm. Table
I presents the demograph ic feamres and Table II dem-
onstrates the labor characteristics of these patients. The
patients did not va W significantly with regard to age,
gestational age, or ethnicfly. At randomizat ion, active
m a n a g e m e n t of labor and control patients did no t va U
significantly in dilatation, effacement, inc idence of spo~»
taneous rupture of membranes , or distribution of thick
mecon ium. Patients on the active m a n a g e m e n t pro tocol
received a significantly h igher dose of oxytocin than
those enrol led in the current protocol (13 ± 9 m U / h r vs
6 + ä m U / h r , p = 0.001). Nevertheless, u ter ine hype>
st imulation was no t seen with any greater B'equency in
the active m a n a g e m e n t g roup compared with the control
group (11% versus 8%, p = 0.31). In both groups rnore
than half of the patients requ i red labor augmenta t ion
(active m a n a g e m e n t 56%, control 51%). Approximate ly
equal numbers of the patients in each group reques ted
and received epidural analgesics for pain control (59% and 51%, respectively).
Table III details the dura t ion o f labor in the various subgroups. The length of labor in the active manage-
m e n t group was reduced by 102 minutes when, compared
with controls (p = 0.001). Patients in e i ther group who
requi red oxytocin augmenta t ion had longer labors than
their n o n a u g m e n t e d counterparts , as did patients who
received epidnral analgesics. Patients in the active man-
agemen t group who received epidural analgesics bad the
first stage of labor significant]y shor tened by an average
of 2 hours as compared with the controts. This relation-
ship persisted in the active m a n a g m e n t patients with
epidural analgesia whe ther they also requ i red or did no t
requi re augmenta t ion of labor. The lengths o f the sec-
ond and third stages of labor were not significantly
different across subgroups. Finally, in the contro! group
of patients who were delivered vaginally, 41% labored
>12 hours. In the actively managed group only 25~
labored >12 hours. This difference was statisticatly sig-
nificant (p = 0.01) and persisted despite the use of
epidnal analgesia (active managemen t 51% vs contro!
66%, p = 0.03).
Table IV demonst ra tes that there was no s~gnificant
difference in the n u m b e r o f patients achieving spontane-
ous vaginal delivery between the two groups (81% in the
active m a n a g e m e n t group and 82% in controls) . T h e
rates of operat ive vaginal delivery ",vere comparab le in
602 F:logers et at. September 1997 .~n J Obstet Gynecol
Table IV. Mode of delivery
All patients
Active management (n = 200) 1 Control (n = 205) Signi ficance
Total vaginal deliveries (No.) 185 (92.5%) 181 (88.3%) NS Spontaneous 150 (81%) 148 (82%) NS Forceps or vacuum 35 (19%) 33 (18%) NS
Total cesarean sections (No.) 15 (7.5%) 24 (11.7%) NS Arrest of dilatation 9 (60%) 16 (67%) NS Arrest of descent 4 (27%) 5 (21%) NS Fetal intolerance 2 (13%) 3 (12%) NS
Table V. Outcomes in patients receiving either epidural analgesics or oxytocin augmentation, or both
] Length of (hr) section No. labor Cesarean
All patients receiving oxytocin augmentation (n = 217) Controls (n = 105) Active management (n = 112)
All patients receiving epidural analgesia (n = 230) Controls (n = 131) Active management (n = 126)
Epidural analgesia and augmentation (n = 145) Controls (n = 82) Active management (n = 86)
Epidural analgesia without augmentation (n = 85) Controls (n = 49) Active management (n = 40)
13.1 + 4.8* 20 (19%) 11.6 +-_ 4.7* 12 (10.7%)
13.3 Z 5.2t 20 (15.3%) 11.2 + 4.6 t 14 (11.1%)
14.1 + 4.6 + 16 (19.5%) 12.3 2 4.7 + 12 (14.0%)
12.1 +- 5.9§ 4 (8.2%) 8.8 -+ 3.4§ 2 (5.0%)
*p = 0.03.
tP = 0.001. +p = 0.02. §p = 0.002.
the two groups (19% and 18%, respectively). There were
15 cesarean sections in the active management group
(7.5%) and 24 in the control group (11.7%), a reduction
of 36% in the actively managed group, which was not
significant. The indications for either an operative vagi-
nal delivery or a cesarean secUon were not different
between groups, with 9 patients in the active manage-
ment group and 16 in the control group undergoing
eesarean section for arrest of dilatation in first-stage
labor, implying a trend toward the reduction of dystocia
in the active management patients. The rate of second-
stage cesarean secuons was 2.0% among active manage-
ment patients and 2.4% among usual care patients.
Among patients who received epidural analgesics, the
cesarean section rate was 11.1% among the patients
being actively managed and 15.3% in the control group.
Among those patients who did not receive epidural
analgesics, the overall rate of cesarean section was ex-
tremely low at 2.7%. Table V stratifies the data on length
of labor and mode of delivery by whether patients
received either epidural analgesics or augmentation, or
both. The patients who were augmented under the active
management protocol had a signifieantly shorter length
of labor (mean 90-minute reducüon, p = 0.03). Those
patients who had epidural analgesia and augmentation
according to the active management protocol, as well as
those with epidural analgesia in the active management
group who did not receive augmentation, also had
shorter lengths of labor (mean 108-minute reduetion,
p = 0.02, and mean 198-minute reduction, p = 0.002,
respectively). Thirty-four of the the 39 total cesarean
deliveries were carried out in patients who had reeeived
epidural analgesics. Delivery complications between the
two groups were equivalent. Four percent of active
management paäents and 7% of controls had postpar-
mm hemorrhage (defined as estimated blood loss >500
tal), and 14% and 13%, respectively, of the patients in
eaeh group experienced febrile episodes during labor
attributable to chorioamnionitis. Table VI details the
neonatal outcomes. Apgar scores, fetal weights, and
neonatal outcomes did not vary signifieantly between
groups.
Comment
For >25 years active management of labor has been
successfully used at the National Maternity Hospital in
Dublin according to the protocol instituted by O'Driscoll
et al. 2 The basis of active management rests on the tenets
of an accurate diagnosis of true labor, early amniotomy,
selective use of high-dose oxytocin, limitation of the total
Volume 177, Number 3 Flogers et aJ. 603 Am J Obstet Gynecol
Table VI. Neonatal outcomes
Active management (n = 200) Control (n = 205) 1 Significance
Infant weight (gm) 3300 +_ 405 3245 + 417 NS Apgar score <7 at 5 min 2 2 NS NICU admission 1 4 NS Cord pH <7.00 2 2 NS
duration of labor to 12 hours, supportive maternal intrapartum care, and antenatal education. In 1984
O'Driscoll et al. 6 investigated a group of 8742 women
who all underwent active management of labor, of whom
3106 were nulliparous and 5636 were multiparous. The
cesarean section rate was 5.5% for the nulliparous
women and 2.8% among the multiparous ones. They
ascribed the higher rate of dystocia in the nulliparous
patients to inadequate uterine activity and the need to
overcome the increased soft tissue resistance of the
untried birth canal. They touted oxytocin as the only
reasonable alternative to cesarean section.
Other investigators have further evaluated active man- agement of labor as described by O'Driscoll et al. Four of
these studies used historic controls and did not random- ize patients. 9~2 An analysis of these retrospective studies
reveals significant decreases in the cesarean section rates
and modest declines in the rates of operative vaginal
deliveries. Not all studies commented on lengths of
labor, but in those that did, patients in the active
management groups had shorter overall durations of
labor, most notably in first-stage labor. None of the
studies showed any increase in the incidence of poor neonatal outcome in the patients who received active
management. Satin et at. 13 noted that a given patient's
response to the dosage of o~,e/tocin was hig-hly variable and precluded prediction of the mode of delivery, im-
plying that other factors besides oxytocin may account
for the favorable outcomes noted in these studies.
Two prospective randomized controlled trials have
been published in the United States, those of Lopez- Zeno et al. 7 and of Frigoletto et al. s Both of these studies
used the same tenets espoused here, namely, early diag- nosis of true labor, early atnniotomy, amt high-dose
oxytocin. Lopez-Zeno et al. ~ randomly assigned 351
women to active management of labor and 354 to the
control g roup Length of labor in the active management
group was shortened by 1.7 hours, with a 15% decrease in the cesarean section rate, from 10.5% in the active management patients to 14.1% in the control group. Frigoletto et aL e randomly assigned 1017 women to
active management and 917 women to usual care in their
study. They reproduced all the tenets of the work of O'Driscoll et al., including antenatal education and one-on-one nursing. Length of labor was significantly shortened by 2.7 hours (6.2 vs 8.9 hours), and the cesarean section rate was reduced 18% in the active
management group compared with controIs (9.2% vs
11.3%, p not significant), confirming the findings of
Lopez-Zeno et al. The results of the current study show a 36% lower
cesarean section rate in the active management group
compared with the conventionally managed group, a
difference consistent with the aforementioned larger
studies and not significant. The overall cesarean section
rate for study participants was 9.6%, with a rate of 7.5%
in the actively managed patients and a rate of 11.7% in
the usual care group. The cesarean delivery rate in the
study patients was lower than the overall institutional rate
of 14.5% over the same study period but comparable to
our rate of 10.9% for nulliparous patients with uncom- plicated term gestations. It would have been preferable
for us to perform an initial power study that was based on
our institutional cesarean section rate for nutliparous
patients with uncomplicated term gestations of 10.9%.
More relevantly, a poststudy power analysis that was
based on our results demonstrated that it would have
required 765 subjects in each arm to achieve 80% power
for this end point. We believed it reasonable to stop with
the number of subjects we did recruit, but this explains
the low power we actually achieved for demonstrating a reduction in the cesarean section rate. A multicenter
collaborative trial or a metaanalysis of the existing ran-
domized controlled trials may better address this key
issue.
The current study did show a significant decrease in
the length of labor of the actively managed patients,
which persisted despite a high use of epidural analgesics
(Tables III and V). Finally, this study confirms that,
despite the use of high-dose ox-y.tocin, there was no
evidence of increased fetal intolerance of labor with this
method of labor management. There were two fetuses in
the actively managed group with fetal intolerance of
labor as the indication for abdominal delivery and three fetuses in the usual care group. There were no long-term
adverse neonatal outcomes in this sample. The incidence of a febrile episode during labor was 14% in tile active
management group and 13% in the control group. Factors hypothesized to be contributing to the increas-
ing rate of cesarean section in the United States include
the use of epidural analgesics, the lack of support of the
parturient patient during labor, and the fear oflitigati0n. The increasing use of epidural analgesics has been suggested by some to be a factor contributing signifi-
604 Roger8 et al. September 1997 ,~n J Obstet Gynecol
cantly to the increasing inc idence of cesarean delivery
for dystocia in nul l iparous w o m e n and has been a cause
of conce rn and controversy in the Uni ted States. Five
prospective studies 14-1s have looked at this issue and have
demons t ra ted that the respective cesarean section rates
be tween the no epidural and epidural groups were 7.1%
and 21.0% (p < 0.05). The a rgumen t has been advanced
that patients exper ienc ing longer, dysfunctional, and
more painful labors are more likely to choose epidural
analgesia, thus preselect ing themselves to be more likely
to unde rgo cesarean delivery and the reby biasing the
studies. It is then reasonable to investigate whe ther
augmenta t ion of desultory labor after the fashion of the
active m a n a g e m e n t protocols migh t be able to overcome
the apparen t deleter ious effect of epidural analgesia on
labor progress. The cur ren t study shows an overall cesar-
ean section rate of 9.6%. A m o n g all patients with epi-
dural analgesia the cesarean section rate was 13.6%,
lower than that observed in previous r andomized studies.
Within this group patients with augmenta t ion unde r the
active m a n a g e m e n t pro tocol had a rate of 11.1% and
controls had a rate of 15.3%, a nonsignif icant difference.
Nevertheless, the length of labor in these patients was
r educed a m e a n of 126 minutes (p = 0.001), which we
believe is clinically relevant. Finally, among those pa-
tients who did no t receive epidural analgesics, the overall
rate of cesarean section was extremely low at 2.7%. Thus
the vast majori ty of cesarean sections were pe r fo rmed on
patients with epidural analgesia p laced for rel ief of pain
dur ing first-stage labor, making the implicat ions of our
f indings regarding active m a n a g e m e n t o f labor and
epidural analgesia clinically very useful.
O h r study cont inues to suppor t previous observations
that actively managed labor leads to shorter labors re-
gardless of the need for augmenta t ion or epidural anal-
gesia. The benefi t o f this m o d e of labor m a n a g e m e n t
may be its ability to identify the onset of true labor and to
decrease the total length of labor. The onset of labor in
nul l iparous patients he re was based on effacement and
regular painful contractions, ra ther than on Fr iedman ' s
def ini t ion of dilatation and regular painful contrac-
tions. 19 The cur ren t study questions the s tandard d ic tum
that active labor does no t c o m m e n c e unti l the par tur ien t
reaches a cervical dilatation of 3 to 4 cm. Hefe , as weil as
in o ther studies, patients were admi t ted with less cervical
dilatation bu t with more advanced effacement and with a
decrease in the length of labor, as well as a decrease in
cesarean section rates.
Patients in the active m a n a g e m e n t arm of the current
study had m e m b r a n e s rup tu red on admission at an
average of 2.8 cm of cmwical dilatation. Recent studies of
early amnio tomy 2°-22 have shown the total dura t ion of
labor to be r educed by an average of only 92 minutes
with no reduc t ion in the cesarean section rate after
amnio tomy p e r f o r m e d before late-active-phase labor.
These studies involved a total of 2750 subjects; however,
they demons t ra ted very little difference between groups
as regards cervical dilatation at the t ime of amniotomy.
"One-on-one" parturient-midwife labor is also a critical
aspect of actively managed labor in Ireland, and its
benefits have been no ted by o t h e r s Y In this study nurses
were usually, assigned to two laboring patients at a time,
and certified nurse-midwives did no t participate in the
study, no t duplicat ing this aspect of the Dublin experi-
ence. In addit ion, there was no r igorous a t tempt at
antenatal educat ion, ano the r central tenet of active
m a n a g e m e n t as pract iced in Ireland.
In summary, active manageraen t of labor in nullipa-
rous women shortens the dura t ion of labor, increases the
l ikel ihood of delivery within 12 honrs, and overcomes
the delay in delivery associated with the use of epidural
analgesia. Whereas there was a t rend toward a lower
inc idence of cesarean section in the actively managed
group, this reduc t ion did no t reach statistical signifi-
cance compared wirb o u t institutional rate for low-risk
nulligravid women. Nevertheless, the degree of reduc-
tion achieved may be clinically significant, especially in
the paüents receiving epidural analgesics. Fur ther trials
of the efficacy and safety of active m a n a g e m e n t of labor
seem warranted as we cont inue our efforts to lower the
rate of abdomina l delivery in the Uni ted States. A
collaborative mul t icenter trial or fur ther combined indi-
vidual trials subjected to a metaanalysis will be necessary
to attain the power needed for a definitive s ta tement on
the efflcacy of this m o d e of labor m a n a g e m e n t as regards
lowering the cesarean section rate.
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Volume 177, Number 3 Rogers et al. 605 Am J Obstet Gynecol
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