When assessing the duration of labor contractions by palpation the nurse should time from the?

Cervical change occurs at a slow, gradual pace during the latent phase of the first stage of labor. Latent phase of labor is complex and not well-studied since determination of onset is subjective and may be challenging as women present for assessment at different time duration and cervical dilation during labor. In a cohort of women undergoing induction of labor, the median duration of latent labor was 384min with an interquartile range of 240-604 min. The authors report that cervical status at admission for labor induction, but not other risk factors typically associated with cesarean delivery, is associated with length of the latent phase. [38]

Most women experience onset of labor without premature rupture of the membranes (PROM); however, approximately 8% of term pregnancies is complicated by PROM. Spontaneous onset of labor usually follows PROM such that 50% of women with PROM who were expectantly managed delivered within 5 hours, and 95% gave birth within 28 hours of PROM. [39] Currently, the American College of Obstetricians and Gynecologists (ACOG) recommends that fetal heart rate monitoring should be used to assess fetal status and dating criteria reviewed, and group B streptococcal prophylaxis be given based on prior culture results or risk factors of cultures not available. Additionally, randomized controlled trials to date suggest that for women with PROM at term, labor induction, usually with oxytocin infusion, at time of presentation can reduce the risk of chorioamnionitis. [40]

According to Friedman and colleagues, [6] the rate of cervical dilation should be at least 1 cm/h in a nulliparous woman and 1.2 cm/h in a multiparous woman during the active phase of labor. However, labor management has changed substantially during the last quarter century. Particularly, obstetric interventions such as induction of labor, augmentation of labor with oxytocin administration, use of regional anesthesia for pain control, and continuous fetal heart rate monitoring are increasingly common practice in the management of labor in today’s obstetric population. [41, 42, 20] Vaginal breech and mid- or high-forceps deliveries are now rarely performed. [43, 44, 45] Therefore, subsequent authors have suggested normal labor may precede at a rate less rapid than those previously described. [8, 9, 20]

Data collected from the Consortium on Safe Labor suggests that allowing labor to continue longer before 6-cm dilation may reduce the rate of intrapartum and subsequent cesarean deliveries in the United States. [46] In the study, the authors noted that the 95th percentile for advancing from 4-cm dilation to 5-cm dilation was longer than 6 hours; and the 95th percentile for advancing from 5-cm dilation to 6-cm dilation was longer than 3 hours, regardless of the patient’s parity.

On admission to the Labor and Delivery suite, a woman having normal labor should be encouraged to assume the position that she finds most comfortable. Possibilities including walking, lying supine, sitting, or resting in a left lateral decubitus position. Of note, ambulating during labor did not change the progression of labor in a large randomized controlled study of >1000 women in active labor. [47]

The patient and her family or support team should be consulted regarding the risks and benefits of various interventions, such as the augmentation of labor using oxytocin, artificial rupture of the membranes, methods and pharmacologic agents for pain control, and operative vaginal delivery (including forceps or vacuum-assisted vaginal deliveries) or cesarean delivery. They should be actively involved, and their preferences should be considered in the management decisions made during labor and delivery. [2]

The frequency and strength of uterine contractions and changes in cervix and in the fetus' station and position should be assessed periodically to evaluate the progression of labor. Although progression must be monitored, vaginal examinations should be performed only when necessary to minimize the risk of chorioamnionitis, particularly in women whose amniotic membrane has ruptured. During the first stage of labor, fetal well-being can be assessed by monitoring the fetal heart rate at least every 15 minutes, particularly during and immediately after uterine contractions. In most labor and delivery units, the fetal heart rate is assessed continuously. [3]

Two methods of augmenting labor have been established. The traditional method involves the use of low doses of oxytocin with long intervals between dose increments. For example, low-dose infusion of oxytocin is started at 1 mili IU/min and increased by 1-2 mili IU/min every 20-30 minutes until adequate uterine contraction is obtained. [2]

The second method, or active management of labor, involves a protocol of clinical management that aims to optimize uterine contractions and shorten labor. This protocol includes strict criteria for admission to the labor and delivery unit, early amniotomy, hourly cervical examinations, early diagnosis of inefficient uterine activity (if the cervical dilation rate is < 1.0 cm/h), and high-dose oxytocin infusion if uterine activity is inefficient. Oxytocin infusion starts at 4 mili IU/min (or even 6 mili IU/min) and increases by 4 mili IU/min (or 6 mili IU/min) every 15 minutes until a rate of 7 contractions per 15 minutes is achieved or until the maximum infusion rate of 36 mili IU/min is reached. [48, 2]

Although active management of labor was originally intended to shorten the length of labor in nulliparous women, its application at the National Maternity Hospital in Dublin produced a primary cesarean delivery rate of 5-6% in nulliparas. [49] Data from randomized controlled trials confirmed that active management of labor shortens the first stage of labor and reduces the likelihood of maternal febrile morbidity, but it does not consistently decrease the probability of cesarean delivery. [50, 51, 52]

Although the active management protocol likely leads to early diagnosis and interventions for labor dystocia, a number of risk factors are associated with a failure of labor to progress during the first stage. These risk factors include premature rupture of the membranes (PROM), nulliparity, induction of labor, increasing maternal age, and or other complications (eg, previous perinatal death, pregestational or gestational diabetes mellitus, hypertension, infertility treatment). [53, 54]

While the ACOG defines labor dystocia as abnormal labor that results form abnormalities of the power (uterine contractions or maternal expulsive forces), the passenger (position, size, or presentation of the fetus), or the passage (pelvis or soft tissues), labor dystocia can rarely be diagnosed with certainty. [1] Often, a "failure to progress" in the first stage is diagnosed if uterine contraction pattern exceeds 200 Montevideo units for 2 hours without cervical change during the active phase of labor is encountered. [1] Thus, the traditional criteria to diagnose active-phase arrest are cervical dilatation of at least 4 cm, cervical changes of < 1 cm in 2 hours, and a uterine contraction pattern of >200 Montevideo units. These findings are also a common indication for cesarean delivery.

Proceeding to cesarean delivery in this setting, or the "2-hour rule," was challenged in a clinical trial of 542 women with active phase arrest. [55] In this cohort of women diagnosed with active phase arrest, oxytocin was started, and cesarean delivery was not performed for labor arrest until adequate uterine contraction lasted at least 4 hours (>200 Montevideo units) or until oxytocin augmentation was given for 6 hours if this contraction pattern could not be achieved. This protocol achieved vaginal delivery rates of 56-61% in nulliparas and 88% in multiparas without severe adverse maternal or neonatal outcomes. Therefore, extending the criteria for active-phase labor arrest from 2 to at least 4 hours appears to be effective in achieving vaginal birth. [55, 1]

When the woman enters the second stage of labor with complete cervical dilatation, the fetal heart rate should be monitored or auscultated at least every 5 minutes and after each contraction during the second stage. [3] Although the parturient may be encouraged to actively push in concordance with the contractions during the second stage, many women with epidural anesthesia who do not feel the urge to push may allow the fetus to descend passively, with a period of rest before active pushing begins.

A number of randomized controlled trials have shown that, in nulliparous women, delayed pushing, or passive descend, is not associated with adverse perinatal outcomes or an increased risk for operative deliveries despite an often prolonged second stage of labor. [56, 57, 39] Furthermore, investigators who recently compared obstetric outcomes associated with coached versus uncoached pushing during the second stage reported a slightly shortened second stage (13 min) in the coached group, with no differences in the immediate maternal or neonatal outcomes. [58]

Le Ray et al reported that manual rotation of fetuses who were in occiput posterior or occiput transverse position at full dilatation was associated with reduced rates of operative delivery (ie, cesarean or instrumental vaginal delivery). [59, 60] In a study involving 2 French hospitals, operative delivery rates were significantly lower at the institution whose policy favored manual rotation than at the one that favored modification of maternal position (23.2% vs 38.7%), mainly because of lower rates of instrumental deliveries (15.0% vs 28.8%).

When a prolonged second stage of labor is encountered, clinical assessment of the parturient, the fetus, and the expulsive forces is warranted. A randomized controlled trial performed by Api et al determined that application of fundal pressure on the uterus does not shorten the second stage of labor. [61] Although the 2003 ACOG practice guidelines state that the duration of the second stage alone does not mandate intervention by operative vaginal delivery or cesarean delivery if progress is being made, the clinician has several management options (continuing observation/expectant management, operative vaginal delivery by forceps or vacuum-assisted vaginal delivery, or cesarean delivery) when second-stage arrest is diagnosed.

The association between a prolonged second stage of labor and adverse maternal or neonatal outcome has been examined. While a prolonged second stage is not associated with adverse neonatal outcomes in nulliparas, possibly because of close fetal surveillance during labor, but it is associated with increased maternal morbidity, including higher likelihood of operative vaginal delivery and cesarean delivery, postpartum hemorrhage, third- or fourth-degree perineal lacerations, and peripartum infection. [11, 12, 13, 14] Therefore, it is crucial to weigh the risks of operative delivery against the potential benefits of continuing labor in hopes to achieve vaginal delivery. The question of when to intervene should involve a thorough evaluation of the ongoing risks of further expectant management versus the risks of intervention with vaginal or cesarean delivery, as well as the patients' preferences.

When delivery is imminent, the mother is usually positioned supine with her knees bent (ie, dorsal lithotomy position), though delivery can occur with the mother in any position, including the lateral (Sims) position, the partial sitting or squatting position, or on her hands and knees. [2] Although an episiotomy (an incision continuous with the vaginal introitus) used to be routinely performed at this time, the ACOG recommended in 2006 that its use be restricted to maternal or fetal indications. Studies have also shown that routine episiotomy does not decrease the risk of severe perineal lacerations during forceps or vacuum-assisted vaginal deliveries. [62, 63]

Crowning is the word used to describe when the fetal head forcibly extends the vaginal outlet. A modified Ritgen maneuver can be performed to deliver the head. Draped with a sterile towel, the heel of the clinician's hand is placed over the posterior perineum overlying the fetal chin, and pressure is applied upward to extend the fetus' head. The other hand is placed over the fetus' occiput, with pressure applied downward to flex its head. Thus, the head is held in mid position until it is delivered, followed by suctioning of the oropharynx and nares. Check the fetus' neck for a wrapped umbilical cord, and promptly reduce it if possible. If the cord is wrapped too tightly to be removed, the cord can be double clamped and cut. Of note, some providers, in an attempt to avoid shoulder dystocia, deliver the anterior shoulder prior to restitution of the fetal head.

Next, the fetus' anterior shoulder is delivered with gentle downward traction on its head and chin. Subsequent upward pressure in the opposite direction facilitates delivery of the posterior shoulder. The rest of the fetus should now be easily delivered with gentle traction away from the mother. If not done previously, the cord is clamped and cut. The baby is vigorously stimulated and dried and then transferred to the care of the waiting attendants or placed on the mother's abdomen.

The labor process has now entered the third stage, ie, delivery of the placenta. Three classic signs indicate that the placenta has separated from the uterus: (1) The uterus contracts and rises, (2) the cord suddenly lengthens, and (3) a gush of blood occurs. [2]

Delivery of the placenta usually happens within 5-10 minutes after delivery of the fetus, but it is considered normal up to 30 minutes after delivery of the fetus. Excessive traction should not be applied to the cord to avoid inverting the uterus, which can cause severe postpartum hemorrhage and is an obstetric emergency. The placenta can also be manually separated by passing a hand between the placenta and uterine wall. After the placenta is delivered, inspect it for completeness and for the presence of 1 umbilical vein and 2 umbilical arteries. Oxytocin can be administered throughout the third stage to facilitate placental separation by inducing uterine contractions and to decrease bleeding.

Expectant management of the third stage involves allowing the placenta to deliver spontaneously, whereas active management involves administration of uterotonic agent (usually oxytocin, an ergot alkaloid, or prostaglandins) before the placenta is delivered. This is done with early clamping and cutting of the cord and with controlled traction on the cord while placental separation and delivery are awaited.

A review of 5 randomized trials comparing active versus expectant management of the third stage demonstrated that active management was associated with lowered risks of maternal blood loss, postpartum hemorrhage, and prolongation of the third stage, but it increased maternal nausea, vomiting, and blood pressure (when ergometrine was used). However, given the reduced risk of complications, this review recommends that active management is superior to expectant management and should be the routine management of choice. [19] A multicenter, randomized, controlled trial of the efficacy of misoprostol (prostaglandin E1 analog) compared with oxytocin showed that oxytocin 10 IU IV or given intramuscularly (IM) was preferable to oral misoprostol 600 mcg for active management of the third stage of labor in hospital settings. [64] Therefore, if the risks and benefits are balanced, active management with oxytocin may be considered a part of routine management of the third stage. A study by Adnan et al that included 1075 women to compare intravenous oxytocin and intramuscular oxytocin for the third stage of labor reported that although intravenous oxytocin did not lower the incidence of standard postpartum hemorrhage, it significantly lowered the incidence of severe postpartum hemorrhage as well as lowering the frequency of blood transfusion and admission to a high dependency unit. [76]

After the placenta is delivered, the labor and delivery period is complete. Palpate the patient's abdomen to confirm reduction in the size of the uterus and its firmness. Ongoing blood loss and a boggy uterus suggest uterine atony. A thorough examination of the birth canal, including the cervix and the vagina, the perineum, and the distal rectum, is warranted, and repair of episiotomy or perineal/vaginal lacerations should be carried out.

Franchi et al found that topically applied lidocaine-prilocaine (EMLA) cream was an effective and satisfactory alternative to mepivacaine infiltration for pain relief during perineal repair. In a randomized trial of 61 women with either an episiotomy or a perineal laceration after vaginal delivery, women in the EMLA group had lower pain scores than those in the mepivacaine group (1.7 +/- 2.4 vs 3.9 +/- 2.4; P = .0002), and a significantly higher proportion of women expressed satisfaction with anesthesia method in the EMLA group than in the mepivacaine group (83.8% vs 53.3%; P = .01). [65]

In a Cochrane review, Aasheim et al suggest that evidence is sufficient to support the use of warm compresses to prevent perineal tears. They also found a reduction in third-degree and fourth-degree tears with massage of the perineum to reduce the rate of episiotomy. [66]

The World Health Organization developed a checklist to address the major causes of maternal death (hemorrhage, infection, obstructed labor and hypertensive disorders), intrapartum-related stillbirths (inadequate intrapartum care), and neonatal deaths (birth asphyxia, infection and complications related to prematurity). [67, 68]