The length of the first stage of labor varies greatly but is usually shorter as parity increases. Full dilation may occur in less than 1 hour in some multiparous pregnancies. In first-time pregnancy, complete dilation of the cervix can take up to 20 hours. The second stage of labor lasts an average of 20 minutes for a multiparous woman and 50 minutes for a nulliparous woman.
Common appearance and behavior of women during each phase of the first stage of labor are listed in Box 3-2.
Procedure
Tests for Rupture of Membranes
Nitrazine Test FOR pH
Procedure
Read Results
Yellow | pH 5.0 |
Olive-yellow | pH 5.5 |
Olive-green | pH 6.0 |
Blue-green | pH 6.5 |
Blue-gray | pH 7.0 |
Deep blue | pH 7.5 |
Document Results
Test for Ferning or Fern Pattern
Document Results
BOX 3-2
Common Characteristics of First-Stage Labor
Latent Phase (dilation of cervix 0-3 cm; contractions 30-45 sec long, 5-30 min apart, mild to moderate intensity; duration of phase about 6-8 hr)
Active Phase (dilation of cervix 4-7 cm; contractions 40-70 sec long, 3-5 min apart, moderate to strong intensity; duration of phase about 3-6 hr)
Transition Phase (dilation of cervix 8-10 cm; contractions 45-90 sec long, 2-3 min apart, strong intensity; duration of phase about 20-40 min)
Nursing care for women during the first stage of labor is described in Box 3-3.
BOX 3-3
Nursing Care in First-Stage Labor
Assessment
Interventions
Because labor is a period of physiologic stress for the fetus, frequent monitoring of fetal status is part of the nursing care during labor. The goals of intrapartum FHR monitoring are to identify and differentiate the normal (reassuring) patterns from the abnormal (nonreassuring) patterns, which can be indicative of fetal compromise. Fetal well-being during labor can be assessed by the response of the FHR to uterine contractions.
BOX 3-4
Procedure for Intermittent Auscultation of the Fetal Heart Rate
1. Palpate the maternal abdomen to identify fetal presentation and position.
2. Apply ultrasonic gel to the device if using a Doppler ultrasound. Place the listening device over the area of maximal intensity and clarity of the fetal heart sounds to obtain the clearest and loudest sound, which is easiest to count. This location will usually be over the fetal back. If using the fetoscope, firm pressure may be needed.
3. Count the maternal radial pulse while listening to the fetal heart rate (FHR) to differentiate it from the fetal rate.
4. Palpate the abdomen for the presence or absence of uterine activity (UA) so as to count the FHR between contractions.
5. Count the FHR for 30 to 60 sec between contractions to identify the auscultated rate, best assessed in the absence of UA.
6. Auscultate the FHR before, during, and after a contraction to identify the FHR during the contraction, as a response to the contraction, and to assess for the absence or presence of increases or decreases in FHR.
7. When distinct discrepancies in the FHR are noted during listening periods, auscultate for a longer period during, after, and between contractions to identify significant changes that may indicate the need for another mode of FHR monitoring.
Source: Tucker, S., Miller, L., & Miller, D. (2009). Mosby’s pocket guide to fetal monitoring: A multidisciplinary approach (6th ed.). St. Louis: Mosby.
NURSING ALERT
When the FHR is auscultated and documented, it is inappropriate to use the descriptive terms associated with electronic fetal monitoring (e.g., moderate variability, variable deceleration) because most of the terms are visual descriptions of the patterns produced on the monitor tracing. Terms that are numerically defined, however, such as bradycardia and tachycardia, can be used. Fetal heart rate when auscultated should be described as a baseline number or range, and as having a regular or irregular rhythm. The presence or absence of accelerations or decelerations both during and after contractions should also be noted.
There are two modes of electronic FHR and contraction monitoring: external and internal. See Table 3-1 for differences in these monitoring modes.
TABLE 3-1
External and Internal Modes of Monitoring
EXTERNAL MODE | INTERNAL MODE |
FETAL HEART RATE | |
Ultrasound transducer: High-frequency sound waves reflect mechanical action of the fetal heart. Noninvasive. Does not require rupture of membranes or cervical dilation. Used during both the antepartum and intrapartum periods. | Spiral electrode: Converts the fetal ECG as obtained from the presenting part to the FHR via a cardiotachometer. Can be used only when membranes are ruptured and the cervix is sufficiently dilated during the intrapartum period. Electrode penetrates into fetal presenting part by 1.5 mm and must be attached securely to ensure a good signal. |
UTERINE ACTIVITY | |
Tocotransducer: Monitors frequency and duration of contractions by means of a pressure-sensing device applied to the maternal abdomen. Used during both the antepartum and intrapartum periods. | Intrauterine pressure catheter (IUPC): Monitors the frequency, duration, and intensity of contractions. The two types of IUPCs are a fluid-filled system and a solid catheter. Both measure intrauterine pressure at the catheter tip and convert the pressure into millimeters of mercury on the uterine activity panel of the strip chart. Both can be used only when membranes are ruptured and the cervix is sufficiently dilated during the intrapartum period. |
ECG, Electrocardiogram; FHR, fetal heart rate.
Causes, clinical significance, and nursing interventions for tachycardia and bradycardia are listed in Table 3-2.
TABLE 3-2
Tachycardia and Bradycardia
TACHYCARDIA | BRADYCARDIA |
DEFINITION | |
FHR >160 beats/min lasting >10 min | FHR <110 beats/min lasting >10 min |
POSSIBLE CAUSES | |
Early fetal hypoxemia | Atrioventricular dissociation (heart block) |
Fetal cardiac arrhythmias | Structural defects |
Maternal fever | Viral infections (e.g., cytomegalovirus) |
Infection (including chorioamnionitis) | Medications |
Parasympatholytic drugs (atropine, hydroxyzine) | Fetal heart failure |
β-Sympathomimetic drugs (terbutaline) | Maternal hypoglycemia |
Maternal hyperthyroidism | Maternal hypothermia |
Fetal anemia | |
Drugs (caffeine, cocaine, methamphetamines) | |
CLINICAL SIGNIFICANCE | |
Persistent tachycardia in the absence of periodic changes does not appear serious in terms of neonatal outcome (especially true if tachycardia is associated with maternal fever); tachycardia is abnormal when associated with late decelerations, severe variable decelerations, or absent variability. | Baseline bradycardia alone is not specifically related to fetal oxygenation. The clinical significance of bradycardia depends on the underlying cause and the accompanying FHR patterns, including variability, accelerations, or decelerations. |
NURSING INTERVENTIONS | |
Dependent on cause; reduce maternal fever with antipyretics as ordered and cooling measures; oxygen at 8 or 10 L/min by nonrebreather face mask may be of some value; carry out health care provider’s orders based on alleviating cause. | Dependent on cause |
FHR, fetal heart rate.
FHR variability: normal irregularity of fetal cardiac rhythm or fluctuations from the baseline FHR of two cycles or more; the four possible categories of variability are absent, minimal, moderate, and marked. Figure 3-4 shows the four possible categories of variability.
Figure 3-5 shows an example of accelerations. Box 3-5 lists causes, clinical significance, and nursing interventions for accelerations.
Figure 3-6 shows an example of early decelerations. Box 3-6 lists causes, clinical significance, and nursing interventions for early decelerations.
Figure 3-7 shows an example of late decelerations. Box 3-7 lists causes, clinical significance, and nursing interventions for late decelerations.
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