Learning Outcome

• Recognize the stages of normal labor
• Distinguish between normal and abnormal labor progression
• Summarize basic medical and nursing therapy for abnormal labor
• Understand the role of amniotomy during labor
• Understand the role of oxytocin in the augmentation of labor
• Discuss the variability of maternal and fetal outcomes based on normal and abnormal labor
• Review the difference between protracted and arrested labor

Introduction

Normal labor is characterized by regular and painful uterine contractions that conclude in progressive labor. A discussion on abnormal labor patterns is reviewed as abnormalities of the first stage (cervical dilation to complete cervical dilation) and the second stage (descent of the presenting part leading to delivery of the baby). The third stage of labor describes the expulsion of the placenta. An overview of labor abnormalities encompasses all the stages of labor. First and second-stage abnormalities are described either as protraction disorders (which means that delivery is progressing but is lower than normal) or as arrest disorders (complete cessation in progress).  Abnormal third-stage labor meriting intervention is placenta retention beyond 30 minutes, as most third stages are concluded within the first 10 to 20 minutes of delivery.[1]

Normal labor is characterized by regular and painful contractions plus cervical change.  Labor is divided into three stages as well as phases within the first stage:

• First Stage: 0-10 cm
  • Latent phase
  • Active phase (begins at 6 cm dilation and ends with complete cervical dilation)
• Second Stage
  • Maternal expulsive efforts and uterine contractions
  • Begins with complete dilation and ends with the delivery of the fetus
• Third Stage
  • Placental delivery

Abnormal labor patterns in the first and second stages of labor are defined as either protraction or arrest disorders. Protracted labor stages indicate that labor is progressing but at a slower pace than expected. Arrest disorders indicate the complete cessation of the progress of cervical dilation and/or descent of the fetal presenting part.  Abnormal third-stage labor warrants intervention when the placenta is retained for > 30 minutes. 

Nursing Diagnosis

The following criteria should be kept in mind when labeling the labor as abnormal:

First Stage Protraction and Arrest

• Latent Phase Protraction:
  • In nulliparas women:  greater than at least 20 hours
  • In multiparas women: greater than at least 14 hours
  •  Due to its variable and slow progression, latent phase protraction alone should not be an indication for cesarean delivery.

• Active Phase (once 6 cm cervical dilation is achieved)
  • No cervical dilation after 4 hours of adequate contractions with ruptured membranes
  • No cervical dilation after 6 hours of inadequate contractions, with ruptured membranes, despite oxytocin administration

Second Stage Protraction and Arrest

• For nulliparous women: more than 3 hours without epidural or 4 hours with an epidural
• For multiparous women: more than 2 hours without epidural or 3 hours with an epidural
• Longer durations may be appropriate with reassuring maternal and fetal status and the continued descent of the fetal presenting part

Causes

The normal progression of labor requires the inspection of three "Ps," representing power, passage, and passenger. The power comes from uterine contractions and maternal expulsive efforts. The passage is the maternal pelvis, and finally, the fetus is the passenger, who may or may not present itself in a favorable position and presentation. Abnormal progress of labor may be related to fetal factors, uterine factors, bony pelvis factors, or a combination of these. The size of the fetus and the capacity of the maternal pelvis are tested as uterine contractions provide propulsion. Asynclitism or extension of the fetal head as well as occiput posterior or transverse position or mentum or brow presentation may also be etiologies of abnormal progress of labor or labor dystocia.[2] Labor abnormalities due to unfavorable fetal or maternal pelvic dynamics may lead to true dystocia requiring a cesarean delivery.[3]

Risk Factors

Risk Factors Associated with Abnormal Labor

• Fetal macrosomia
• Maternal obesity
• Nonreassuring fetal heart rate patterns
• Non-gynecoid maternal pelvimetry
• Non-occiput anterior position
• Nulliparity
• Short stature
• High fetal station at full cervical dilation
• chorioamnionitis
• Post-term pregnancy
• Bandl's ring
• Gestational diabetes
• Hypertensive disorders
• Epidural analgesia

Assessment

Labor begins with regular uterine contractions in addition to cervical dilation and/or effacement. An important aspect of the history to obtain from the patient is at what time the contractions began and how far apart they have been.  An abdominal examination is a key component of an obstetric exam as it provides an estimated fetal weight of the fetus and informs the provider of the fetal presentation. The continuous monitoring of uterine activity discerns how frequent contractions are occurring. Only with internal pressure catheter monitoring can the actual strength of contractions be measured. Digital vaginal exams to evaluate the maternal pelvimetry, bony pelvis shape and capacity, and cervical dilation and effacement occur at various intervals throughout labor. The fetal station is also assessed with these digital exams, and this provides information regarding the descent of the fetal presenting part, an integral piece of information when determining if labor is progressing normally or abnormally.

Evaluation

Determining the progress of labor is a key component of intrapartum care. Maternal uterine activity is assessed by either manual palpation, external tocodynamometry, or internal monitoring with a pressure catheter. With external tocodynamometry, target uterine activity is 3 to 5 contractions in a 10-minute window. The contractions should last 30 to 40 seconds to be effective. Internal intrauterine pressure assessment using a catheter may also be utilized when the amniotic sac is not intact, in which case the actual strength of contractions can be measured. The most common approach to quantitating uterine contractions is by measuring Montevideo units. Montevideo units are calculated by adding the sum of the net contraction pressures in 10 minutes.  Adequate uterine activity is targeted at 200 - 250 Montevideo units.[4] Although this method of assessing uterine contractions has some limitations, no more useful and accurate system has been yet devised.

Medical Management

Documentation of essential obstetric vital signs. 

Oxytocin may be given when indicated, during all stages of labor.

Most labor and delivery units will have an established protocol for the administration of oxytocin that entails the administration of the proper medication and dosage, as well as criteria for an incremental increase as clinically warranted. The protocols also include monitoring maternal and fetal status and avoiding tachysystole and abnormal fetal heart rate patterns. Such protocols allow collaborative care between the nursing staff and the obstetrician.

Therapeutic rest and analgesia may be provided during a prolonged latent phase of the first stage of labor.

In the case of maternal/fetal compromise, immediate preparation for delivery is indicated.

Nursing Management

• Review the history of labor, including onset and duration
• Assess uterine contractile pattern and intensity
• Assess fetal heartbeat by auscultation or by continuous monitoring
• Evaluate the current level of maternal fatigue/emotional stress
• Observe for any signs of infection
• Monitor vitals
• Evaluate the degree of hydration. Note the quantity and type of oral intake
• Encourage change of position and ambulation, as tolerated
• Note signs of fetal distress, cessation of uterine contractions, and presence of vaginal bleeding
• Alert the midwife or physician of any warning signs
• Prepare the patient for cervical examinations and amniotomy, and assist with the exam, when indicated
• Administer pain medication as indicated
• Provide emotional support during labor

When To Seek Help

• Maternal exhaustion
• A nonreassuring fetal heart tracing
• Absence of adequate uterine contractions
• Tachysystole
• Signs of hypovolemia/hypothermia
• Signs of maternal infection, including an elevated temperature
• Category 3 fetal heart rate tracing
• Maternal hypotension from epidural anesthesia

Outcome Identification

• Maternal rest and readiness for delivery
• Reassuring fetal heart rate pattern
• Prevention of infections
• Healthy mother and baby

Monitoring

Monitor the fetus with fetal auscultation or continuous external or internal monitors

Monitor contractions

Check vitals per protocol

Coordination of Care

The best management of labor requires a coordinated interprofessional effort between trained obstetric nurses, midwives, and physicians. Team management may lower the average cesarean section rates and improve overall outcomes. [Level V]

Health Teaching and Health Promotion

Abnormal labor can be a daunting experience for women, especially during the first birth. However, patients must be aware that they can be managed both at home and at a maternity care clinic/hospital, depending on the stage and associated risk factors. Continued education and explanation of the progress of labor and recommended interventions will help promote positive healthcare outcomes and positive reflection of the labor experience.

Discharge Planning

• The patients should be discharged with appropriate analgesia and sedatives as desired, as well as specific instructions on when to return to labor and delivery if they plan to experience early labor at home.
• Patients should be encouraged to stay mobile, in the absence of any contraindications, as it may lead to better outcomes.
• Patients should be well-hydrated and given nourishment either orally or with dextrose IV solutions.
• The patient should have at least one support person during labor.

Pearls and Other issues

With abnormal labor, cesarean delivery can be a life-saving procedure and may be medically necessary. Diligent management of labor aspires to minimize variation between providers as they resort to cesarean delivery for the management of abnormal labor. The new labor-management guidelines published in 2014 aim to decrease cesarean delivery rates and provide the best opportunity to improve outcomes and reduce costs as well as reduce future maternal obstetrical morbidity and mortality.[5]