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Labor
SECTION 7
option to select either recumbency or supervised ambulation
during labor. This policy is in agreement with the American
College of Obstetricians and Gynecologists (2013), which has
concluded that ambulation in labor is not harmful, and mobility may result in greater comfort.
Birthing Position in Second-Stage Labor
Considerable interest has been shown in alternative secondstage labor birth positions and their effect on labor. Gupta and
Hofmeyr (2004) in their Cochrane database review compared
upright positions with supine or lithotomy positions. Upright
positions included sitting in a “birthing chair,” kneeling, squatting, or resting with the back at a 30-degree elevation. With these
positions, they found a 4-minute shorter interval to delivery, less
pain, and a lower incidence both of nonreassuring fetal heart rate
patterns and of operative vaginal delivery. There was, however,
an increased rate of blood loss > 500 mL with the upright positions. Berghella and colleagues (2008) hypothesized that parity,
less intense aortocaval compression, improved fetal alignment,
and larger pelvic outlet diameters might explain these findings.
In an earlier study, Russell (1969) described a 20- to 30-percent
increase in the area of the pelvic outlet with squatting compared
with that in the supine position. Finally, Babayer and associates
(1998) cautioned that prolonged sitting or squatting during the
second stage may cause common fibular nerve neuropathy.
Water Immersion
A birthing tub or bath has been advocated as a means of relaxation that may contribute to more efficient labor. Cluett and
coworkers (2004) randomly assigned 99 laboring women at term
in first-stage labor identified to have dystocia to immersion in
a birthing pool or to oxytocin augmentation. Water immersion
lowered the rate of epidural analgesia use but did not alter the
rate of operative delivery. More infants of women in the immersion group were admitted to the NICU. These findings were
similar to their subsequent Cochrane database review, except
that NICU admission rates were not increased (Cluett, 2009).
Robertson and associates (1998) reported that immersion
was not associated with chorioamnionitis or uterine infection.
Moreover, Kwee and coworkers (2000) studied the effects
of immersion in 20 women and reported that blood pressure
decreased, whereas fetal heart rate was unaffected. Neonatal complications unique to underwater birth that have been described
include drowning, hyponatremia, waterborne infection, cord
rupture, and polycythemia (Austin, 1997; Pinette, 2004).
PREMATURELY RUPTURED
MEMBRANES AT TERM
Membrane rupture at term without spontaneous uterine contractions complicates approximately 8 percent of pregnancies.
Until recently, management generally included labor stimulation if contractions did not begin after 6 to 12 hours. This
intervention evolved more than 50 years ago because of maternal and fetal complications due to chorioamnionitis (Calkins,
1952). Such routine intervention was the accepted practice
until challenged by Kappy and colleagues (1979). These investigators reported excessive cesarean delivery in term pregnancies
with ruptured membranes managed with labor stimulation
compared with those expectantly managed.
Subsequent research included that of Hannah (1996)
and Peleg (1999) and their associates, who enrolled a total
of 5042 pregnancies with ruptured membranes in a randomized investigation. They measured the effects of induction
versus expectant management and also compared induction
using intravenous oxytocin with that using prostaglandin E2
gel. There were approximately 1200 pregnancies in each of
the four study arms. They concluded that labor induction
with intravenous oxytocin was the preferred management.
This determination was based on significantly fewer intrapartum and postpartum infections in women whose labor was
induced. There were no significant differences in cesarean
delivery rates. Subsequent analysis by Hannah and coworkers
(2000) indicated increased adverse outcomes when expectant
management at home was compared with in-hospital observation. Mozurkewich and associates (2009) reported lower
rates of chorioamnionitis, metritis, and NICU admissions
for women with term ruptured membranes whose labors
were induced compared with those managed expectantly.
At Parkland Hospital, labor is induced soon after admission
when ruptured membranes are confirmed at term. The benefit of prophylactic antibiotics in women with ruptured membranes before labor at term is unclear (Passos, 2012).
PRECIPITOUS LABOR AND DELIVERY
Labor can be too slow, but it also can be abnormally rapid.
Precipitous labor and deliveryy is extremely rapid labor and delivery. It may result from an abnormally low resistance of the soft
parts of the birth canal, from abnormally strong uterine and
abdominal contractions, or rarely from the absence of painful
sensations and thus a lack of awareness of vigorous labor.
According to Hughes (1972), precipitous labor terminates
in expulsion of the fetus in < 3 hours. Using this definition,
89,047 live births—2 percent—were complicated by precipitous labor in the United States during 2006 (Martin, 2009).
Despite this incidence, there is little published information
concerning adverse effects.
■ Maternal Effects
Precipitous labor and delivery seldom are accompanied by serious maternal complications if the cervix is effaced appreciably
and compliant, if the vagina has been stretched previously,
and if the perineum is relaxed. Conversely, vigorous uterine
contractions combined with a long, firm cervix and a noncompliant birth canal may lead to uterine rupture or extensive
lacerations of the cervix, vagina, vulva, or perineum. It is in
these latter circumstances that the rare condition of amnionicfluid embolism most likely develops (Chap. 41, p. 812).
Precipitous labor is frequently followed by uterine atony. The
uterus that contracts with unusual vigor before delivery is likely to
be hypotonic after delivery. Postpartum hemorrhage from uterine
atony is discussed in Chapter 41 (p. 784).
Mahon and colleagues (1994) described 99 pregnancies
delivered within 3 hours of labor onset. Short laborss were
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