Dystocia in Nulliparous Women
SARA G. SHIELDS, MD, MS, University of Massachusetts, Worcester, Massachusetts
STEPHEN D. RATCLIFFE, MD, MSPH, Lancaster General Hospital Family Medicine
Residency Program, Lancaster, Pennsylvania
PATRICIA FONTAINE, MD, MS, University of Minnesota, Minneapolis, Minnesota
LARRY LEEMAN, MD, MPH, University of New Mexico, Albuquerque, New Mexico
mon in nulliparous women, as indicated by
the number requiring augmentation, opera-
tive vaginal delivery, or cesarean section. In
2003, 17 percent of women in the United
States received oxytocin augmentation,1 and
in 2004, the primary cesarean delivery rate
(i.e., cesarean delivery in women without
previous cesarean) rose to 20.6 percent.2
Dystocia is responsible for more than 50 per-
cent of primary cesarean deliveries.3 With the
overall cesarean delivery rate at an all-time
high of 30.2 percent4 (Figure 12,4), optimal
management of dystocia can significantly
impact labor outcomes.
aring for women with dystocia is a
major challenge in maternity care.
Dystocia refers to prolonged or
slowly progressing labor. It is com-
Normal progress in labor was initially defined
by Friedman in the 1950s based on data from
labors of several hundred women.5 Labor
abnormalities are characterized as protrac-
tion or arrest disorders (Table 15,6). To aid in
diagnosis, labor progression may be followed
using a graph called a partogram, which plots
cervical dilation and station across time.7,8
The range of normal labor now appears
to be broader than Friedman’s definitions.
A more recent study of labor progress
among 1,329 nulliparous women deliver-
ing vaginally found it took an average of
5.5 hours to dilate from 4 to 10 cm (a mean
rate of approximately 1.1 cm per hour).9
These findings contrast with Friedman’s
data, which had 1.2-cm dilation per hour
defined as the 95th percentile (i.e., the outer
limit of normal progress).5 The more recent
analysis found that women who had not yet
reached 7 cm dilation often had no cervi-
cal change for more than two hours. Fetal
descent in the second stage of labor also
appeared to take longer.9 Thus, the need for
routine intervention for labor that is pro-
gressive yet protracted is questionable.10
Physicians need to consider four issues when
caring for women with dystocia: (1) if the
contractions are adequate; (2) if there is fetal
malposition; (3) if there is cephalopelvic
Dystocia is common in nulliparous women and is responsible for more than 50 percent of pri-
mary cesarean deliveries. Because cesarean delivery rates continue to rise, physicians providing
maternity care should be skilled in the diagnosis, management, and prevention of dystocia. If
labor is not progressing, inadequate uterine contractions, fetal malposition, or cephalopelvic
disproportion may be the cause. Before resorting to operative delivery for arrested labor, phy-
sicians should ensure that the patient has had adequate uterine contractions for four hours,
using oxytocin infusion for augmentation as needed. For nulliparous women, high-dose
oxytocin-infusion protocols for labor augmentation decrease the time to delivery compared
with low-dose protocols without causing adverse outcomes. The second stage of labor can be
permitted to continue for longer than traditional time limits if fetal monitoring is reassuring
and there is progress in descent. Prevention of dystocia includes encouraging the use of trained
labor support companions, deferring hospital admission until the active phase of labor when
possible, avoiding elective labor induction before 41 weeks’ gestation, and using epidural anal-
gesia judiciously. (Am Fam Physician 2007;75:1671-8. Copyright © 2007 American Academy
of Family Physicians.)
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1672 American Family Physician
Volume 75, Number 11 ◆ June 1, 2007?
disproportion caused by suspected macroso-
mia or a contracted pelvis; and (4) if there are
other coexisting clinical issues (e.g., chorio-
amnionitis, nonreassuring fetal monitoring)
that will impact the treatment options.
firsT sTage of labor
Options for managing the latent phase of labor
include observation, sedation with antihista-
mines or mild narcotics, and labor augmenta-
tion.11 Women being induced may remain in
latent labor for many hours; cesarean delivery
for dystocia should not be performed in
women who remain in latent labor.6,12
Once a woman is in active labor, amni-
otomy before oxytocin use may be suffi-
cient to augment slowly progressing labor.13
Amniotomy with early oxytocin augmenta-
tion shortens labor by as much as two hours
compared with expectant care but has not
been shown to change cesarean delivery
rates.13 Although amniotomy is a simple
procedure, it still carries a risk of causing
increased variable heart rate decelerations
because of cord compression.13 Routine
sorT: KeY reCoMMeNDaTioNs for PraCTiCe
Amniotomy in the first stage of labor results in shorter
labor, but it also may be associated with variable fetal
heart rate decelerations; therefore, it should be reserved
for slowly progressing labors.
High-dose oxytocin regimens result in shorter labors than
low-dose regimens without adverse effects for the fetus.
Women who receive continuous labor support from a
labor support companion use less analgesia, have lower
rates of operative vaginal and cesarean delivery, and are
less likely to report dissatisfaction with their childbirth
Epidural analgesia is associated with a prolongation of the
second stage of labor and an increase in oxytocin use
and operative vaginal delivery.
It is important to follow systematic protocols for diagnosing
labor, assessing its progress, and using oxytocin. Audit
and feedback regarding operative deliveries has been
associated with lower institutional cesarean delivery rates.
A 13 Systematic review
A 18, 19—
A 35 Systematic review; results for each
outcome were derived from at
least four trials including at least
A 46-49 Systematic reviews and a
17, 57, 58
A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-
oriented evidence, usual practice, expert opinion, or case series. For information about the SORT evidence rating system, see page 1605 or
figure 1. Delivery trends in the United States, 1989 to 2005. (VBAC =
vaginal birth after cesarean delivery.)
Adapted with permission from Martin JA, Hamilton BE, Sutton PD, Ventura SJ, Menacker
F, Kirmeyer S. Births: final data for 2004. Natl Vital Stat Rep 2006;55:19 and 71, with addi-
tional information from reference 4.
*—Number of primary cesarean deliveries per 100 live births to women who have
not had a previous cesarean.
†—Percent of all live births by cesarean delivery.
‡—Number of VBAC per 100 live births to women with a previous cesarean delivery.
Primary cesarean rate* Total cesarean rate†
June 1, 2007 ◆ Volume 75, Number 11?
American Family Physician 1673
amniotomy in early labor is not recom-
mended,14 and the role of amniotomy to
treat protracted labor is under review.15
Abdominal palpation or an intrauterine
pressure catheter, which calculates Monte-
video units (MVU), can be used to evalu-
ate the strength and frequency of uterine
contractions in women with protracted- or
arrested-phase labor (Figure 2). MVU of
200 or more in 10 minutes are considered
evidence of adequate contractions.6 Using
an intrauterine pressure catheter may be
important if the contractions seem to be of
sufficient frequency and duration but are
not causing cervical change. A small ran-
domized trial found no difference in labor
duration or cesarean delivery rates when an
intrauterine pressure catheter was used.16
If contractions are inadequate, intra-
venous oxytocin can be administered to
increase frequency, duration, and strength.6
There are numerous approaches to dosage,
dosing interval, and duration of oxytocin
treatment. Low-dose regimens start at 0.5 to
2.0 mU per minute and increase by 1 to
2 mU per minute every 15 to 40 minutes
up to a maximal dose of 20 to 40 mU per
minute.6 High-dose regimens have a start-
ing dose of 6 mU per minute and increase
by 1 to 6 mU per minute up to a maximal
dose of 40 to 42 mU per minute.6,17 In nul-
liparous women who need augmentation,
high-dose oxytocin regimens decrease the
time to delivery by an average of two hours
compared with low-dose regimens without
causing adverse effects for the fetus.18,19
Traditionally, arrested labor has been
defined as having adequate contractions
Table 1. Traditional Definitions of abnormal labor
Stage of labor
> 20 hours
> 14 hours
< 1 cm per hour dilation
≥ 2 hours of active labor
without cervical change
≥ 2 hours of active labor
without cervical change
Multiparous< 1.2 to 1.5 cm per hour
With no regional anesthesia:
> 2 hours duration
< 1 cm per hour descent
With regional anesthesia:
> 3 hours duration
No descent after 1 hour
NA = not applicable.
Information from references 5 and 6.
figure 2. Inadequate uterine contractions as measured by an intrauterine pressure catheter, with continuous tracing of
the FHR (top) and contractions as indicated by uterine pressure (bottom). This representative 10-minute monitor strip
shows three contractions totaling 145 MVU. If MVU are less than 200 in 10 minutes, oxytocin augmentation should be
considered. (FHR = fetal heart rate; bpm = beats per minute; kPa = kilopascal; MVU = Montevideo units.)
FHR 240 bpm
0 mm Hg
50 mm Hg 50 mm Hg 45 mm Hg
ILLUSTRATION BY LARRY P. HOWELL
1674 American Family Physician
Volume 75, Number 11 ◆ June 1, 2007?
for at least two hours without cervical
change; a woman should be observed for at
least that long before resorting to operative
intervention. Extending the time to four
hours before operative treatment has been
shown to decrease the cesarean delivery rate
for arrested labor from 26 to 8 percent.20,21
seCoND sTage of labor
Dystocia in the second stage of labor is char-
acterized by prolonged duration or arrested
descent. This may be caused by fetal malposi-
tion, inadequate contractions, poor maternal
efforts, or true cephalopelvic disproportion.
The most common fetal malposition is
occipitoposterior (i.e., the fetus lying with
the occiput toward the mother’s spine and
face toward the mother’s pubic symphysis).
Typically, the fetus will rotate spontane-
ously to the occipitoanterior position before
delivery, but in 2 to 7 percent of nulliparous
women, the fetus will still deliver in the per-
sistent occipitoposterior position.22,23 This
position is associated with prolonged sec-
ond stage of labor and increased oxytocin
augmentation.22,23 Less than 30 percent of
nulliparous women with a fetus in the per-
sistent occipitoposterior position will have a
spontaneous vaginal delivery.22,23
Occipitoposterior position is diagnosed
by digital vaginal examination, which can
determine the orientation of fetal sutures
and fontanels. If the physician cannot make
this determination, transvaginal sonogra-
phy can confirm fetal head position.24 If a
fetus is in the persistent occipitoposterior
position in the second stage
of labor, manual rotation can
be attempted. Although there
is a lack of high-level evidence
regarding the effectiveness of
interventions for a fetus in
this position, a retrospective
cohort study of 742 women
who underwent attempted manual rota-
tion of a fetus in the occipitoposterior or
occipitotransverse position to the occipi-
toanterior position demonstrated a lower
cesarean delivery rate with successful rota-
tion compared with failed rotation (2 versus
34.3 percent, P < .001).25
Manual rotation is a clinical skill that
requires training and practice. The phy-
sician’s hand is placed palm upward into
the vagina. During a contraction, the hand
serves as a wedge to flex the fetal head while
the fingers exert a rotating force to bring the
occiput to the anterior (Figure 3).26
A variety of maternal positions and
movements have been proposed to resolve
persistent occipitoposterior or asynclitic
fetal positions. These include knee-chest,
hands-and-knees, pelvic rocking, lunging,
side-lying, or asymmetrical sitting or kneel-
ing.27,28 A systematic review concluded that
having a woman assume the hands-and-
knees position for a specified period near the
end of pregnancy had no effect on fetal posi-
tion at delivery; however, no studies were
conducted using women in labor.29
If contractions have decreased in strength
or frequency during the second stage of labor,
intravenous oxytocin can be initiated or
increased.17 Studies have shown that having
women without epidural analgesia push in
an upright or lateral position shortened the
second stage of labor and decreased the risk
of operative vaginal delivery, but this position
increased the risk of second-degree perineal
tears and blood loss of more than 500 mL.30
For women with epidural analgesia, allowing
the fetus to “labor down” to a lower station is
an alternative to initiating active pushing as
soon as cervical dilation is complete. In one
study, delayed pushing increased the incidence
of spontaneous deliveries (relative risk [RR],
1.09; 95% confidence interval [CI], 1.00 to
1.18; number needed to treat [NNT] = 21).31
Prolongation of the second stage of labor
beyond an arbitrary time limit is no longer
an indication for operative vaginal or cesar-
ean delivery. Several studies have demon-
strated the safety to the neonate of extended
second stage labor based on cord blood
gases and five-minute Apgar scores.32-34 A
nonreassuring fetal heart tracing indicates a
need for consideration of operative vaginal
or cesarean delivery.
The incidence of dysfunctional labor in
nulliparous women may be decreased by
Prolongation of the second
stage of labor beyond an
arbitrary time limit is no
longer an indication for
operative vaginal delivery.
June 1, 2007 ◆ Volume 75, Number 11?
American Family Physician 1675
four methods: (1) provision of labor sup-
port; (2) avoidance of hospital admission in
latent stage of labor; (3) avoidance of elective
induction with an unripe cervix; and (4) cau-
tious use of epidural analgesia.
A meta-analysis on the use of a trained
labor support companion (i.e., a doula)
showed that labor support decreases the inci-
dence of dystocia, operative vaginal deliver-
ies, and cesarean deliveries, particularly in
nulliparous women.35 The greatest effects on
labor outcomes occur when a doula rather
than a hospital employee is used, when sup-
port begins early in labor, and when epidural
analgesia is not routinely used.35 Having a
trained nurse rather than a doula provide
continuous labor support does not provide
Nulliparous women presenting to the hos-
pital in the latent stage of labor undergo an
increased number of obstetric interventions.
It remains unclear if this is because of inher-
ent labor abnormality or excessive interven-
tion.37,38 One study showed that avoiding
early hospital admission for women not in
active labor reduced the risk of receiving
augmentation of labor or epidural analgesia
by more than one half.39 Physicians can edu-
cate nulliparous women about when to go
to the hospital. As alternatives to admission
in latent labor, physicians can encourage
adequate hydration, rest, and emotional and
The number of births involving induc-
tion of labor has more than doubled in the
past decade, from 9 percent in 1989 to nearly
21 percent in 2003.1 Elective induction may
be partially responsible for the increasing
rate of cesarean delivery in women with
dystocia. Retrospective or cohort data show
that elective induction results in a two- to
threefold increased risk of cesarean delivery
in nulliparous women with an unripe cervix
despite the use of cervical ripening agents.40,41
Cochrane reviews of misoprostol (Cytotec)
and mechanical methods for cervical ripen-
ing found that they decrease the length of
labor but do not change the overall cesarean
delivery rate.42,43 In contrast, a retrospective
study demonstrated a decreased cesarean
delivery rate through selective induction of
women at full term with specific risk factors
for developing cephalopelvic disproportion or
uteroplacental insufficiency.44 Standard labor
curves may not apply to women undergoing
induction of labor who may have an active
phase longer than expected for spontaneous
labor,45 suggesting a need to permit adequate
time to pass before intervening for dystocia.
Although meta-analyses consistently find
no difference in cesarean delivery rates
among women receiving low-dose epidurals
figure 3. Manual rotation of a fetus in the occipitoposterior position to
the occipitoanterior position. (A) The physician’s hand is placed palm
upward into the vagina. (B) The hand serves as a wedge to flex the
fetal head while the fingers exert a rotating force to bring the occiput
to anterior. (AF = anterior fontanel.)
ILLUSTRATION BY LARRY P. HOWELL
1676 American Family Physician
Volume 75, Number 11 ◆ June 1, 2007?
compared with parenteral opioids,46-49
informed and judicious use of epidural anal-
gesia is important because of the impact on
labor progress and other outcomes. Women
receiving epidurals are more likely to require
oxytocin augmentation in the first stage of
labor, have longer second stages, have persis-
tent occipitoposterior fetal malposition, and
undergo operative vaginal delivery.46-50
Whether administering epidural analgesia
early in labor (before 4 to 5 cm dilation)
increases the risk of cesarean delivery is con-
troversial.51 Epidural analgesia is not a single
entity, and randomized controlled trials that
have specifically investigated early versus
standard (4 to 5 cm cervical dilation) place-
ment are small or do not use contemporary
low-dose techniques.51 The study that is most
commonly cited to support early epidural
use actually compared a combined spinal
epidural analgesia technique (i.e., intrathecal
opioid given at 2 cm cervical dilation) with
an epidural given at 4 cm or later. This study
found no significant differences in labor
duration or cesarean delivery rates.52
Maternal request is a sufficient indication
for pain relief during labor,53,54 and epidurals
are associated with significantly lower pain
scores compared with systemic opioids.46-49
If and when to administer epidural analge-
sia should be individualized. Women with
significant pain early in labor should not be
required to reach 4 to 5 cm cervical dilation
before epidural placement.54 Conversely, a
woman who is informed and prepared to
handle labor pain with lesser interventions
should not be subjected to the expectation
of a routine epidural.
Women who walk or remain upright during
the first stage of labor report greater comfort
and ability to tolerate labor compared with
women who remain recumbent.55 A random-
ized trial comparing women assigned to walk
during early labor with those receiving usual
care showed no differences in the duration of
the first stage of labor, need for oxytocin aug-
mentation, use of analgesia, or rates of opera-
tive vaginal or cesarean delivery. Ambulation
did not decrease dystocia in this study, but it
can be suggested safely because there were no
harmful effects for mothers or infants.56
Finally, certain aspects of physician
style and health care systems may prevent
dystocia and resultant cesarean delivery.
These include caregiver continuity during
the assessment of early labor,17 encourag-
ing a “pronatalist” cultural attitude toward
natural childbirth,57 requiring consultation
with a second physician before nonemergent
cesarean deliveries for dystocia,57 and pro-
viding regular feedback to physicians about
their cesarean delivery rates.58
The authors thank Eugene Bailey, MD, for assistance with
evidence ratings and David Power, MB, MPH, for review
of the manuscript.
This article is one in a series on “Advanced Life Support
in Obstetrics (ALSO),” initially established by Mark
Deutchman, MD, Denver, Colo. The series is now coordi-
nated by Patricia Fontaine, MD, ALSO Managing Editor,
Minneapolis, Minn., and Larry Leeman, MD, ALSO
Associate Editor, Albuquerque, N.M.
ALSO is a registered trademark of the American Academy
of Family Physicians.
SARA G. SHIELDS, MD, MS, is an associate professor of
clinical family medicine and community health at the
University of Massachusetts Medical School and Family
Health Center of Worcester. She received her medical
degree from the University of California, San Francisco,
and completed a family medicine residency at Highland
Hospital and the University of Rochester (N.Y.). Dr. Shields
received a master’s degree in community health and com-
pleted a maternal and child health fellowship at Brown
University in Providence, R.I., and the Memorial Hospital
of Rhode Island in Pawtucket.
STEPHEN D. RATCLIFFE, MD, MSPH, is program director
of the Lancaster (Pa.) General Hospital Family Medicine
Residency Program. He received his medical degree from
Washington University School of Medicine in St. Louis,
Mo. Dr. Ratcliffe also received a master’s degree in public
health from, and completed a family medicine residency
at, the University of Utah in Salt Lake City.
PATRICIA FONTAINE, MD, MS, is an associate profes-
sor of family medicine and community health at the
University of Minnesota in Minneapolis. She received her
medical degree from the University of Michigan Medical
School in Ann Arbor and completed a residency at the
North Memorial Program of the University of Minnesota
Affiliated Family Medicine Residencies. Dr. Fontaine
earned a master’s degree in clinical research as part of an
AAFP Advanced Research Training Grant.
LARRY LEEMAN, MD, MPH, is an associate professor of
family and community medicine and obstetrics and gyne-
cology at the University of New Mexico School of Medicine
in Albuquerque. He is the director of family practice mater-
nity and infant care and the co-medical director of the
June 1, 2007 ◆ Volume 75, Number 11?
American Family Physician 1677
mother-baby unit at the University of New Mexico Hospital
in Albuquerque. After graduating from the University of
California, San Francisco, Dr. Leeman completed a family
medicine residency at the University of New Mexico and a
fellowship in obstetrics at the University of Rochester.
Address correspondence to Sara G. Shields, MD, MS,
University of Massachusetts, Dept. of Family Medicine
and Community Health, Family Health Center of
Worcester, 26 Queen St., Worcester, MA 01610 (e-mail:
sara.shieldsFHCW@umassmed.edu). Reprints are not
available from the authors.
Author disclosure: Nothing to disclose.
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