Term
| NORMAL UTERINE ACTIVITY DURING LABOR: Frequency |
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Definition
| Contraction frequency overall generally ranges from two to five per 10 minutes during labor, with lower frequencies seen in first stage of labor and higher frequencies (up to five contractions in 10 minutes) seen during second stage of labor. The frequency of contractions is measured in minutes, from the beginning of one contraction to the beginning of the next. |
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Term
| NORMAL UTERINE ACTIVITY DURING LABOR: Duration |
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Definition
| Contraction duration remains fairly stable throughout first and second stages, ranging from 45-80 seconds, not generally exceeding 90 seconds. The contraction duration is measured in seconds, from the beginning to the end of the contraction. |
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Term
| NORMAL UTERINE ACTIVITY DURING LABOR: Strength |
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Definition
| Uterine contractions generally range from peaking at 40-70 mm-Hg in first stage of labor to over 80 mm-Hg in second stage. Contractions palpated as “mild” would likely peak at less than 50 mm-Hg if measured internally, whereas contractions palpated as “moderate” or greater would likely peak at 50 mm-Hg or greater if measured internally. The contraction intensity is usually described as mild, moderate, or strong. |
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Term
| NORMAL UTERINE ACTIVITY DURING LABOR: Resting tone |
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Definition
| Average resting tone during labor is 10 mm-Hg; if using palpation, should palpate as “soft” (i.e., easily indented, no palpable resistance). Resting tone between contractions is usually described as soft or relaxed |
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Term
| NORMAL UTERINE ACTIVITY DURING LABOR: Relaxation time |
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Definition
| Relaxation time is commonly 60 seconds or more in first stage and 45 seconds or more in second stage. |
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Term
| NORMAL UTERINE ACTIVITY DURING LABOR: Montevideo units (MVUs) |
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Definition
| MVUs usually range from 100-250 in first stage; may rise to 300-400 in the second stage. Contraction intensities of 40 mm-Hg or more and MVUs of 80-120 are generally sufficient to initiate spontaneous labor. MVUs are used only with internal monitoring of contractions. |
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Term
| steps of INTERMITTENT AUSCULTATION (IA) OF THE FETAL HEART RATE |
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Definition
1. ID fetal presentation and position.
2. Apply gel to device if using Doppler. Place device over area of max intensity of FHR to obtain loudest sound (usually over the fetal back). If using fetoscope, use firm pressure.
3. Count maternal radial pulse while listening to FHR to differentiate it.
4. Palpate abdomen for presence of UA to count FHR between contractions.
5. Count FHR for 30 to 60 seconds after a uterine contraction to ID baseline rate and changes in it.
6. Auscultate FHR before, during, and after contraction to ID FHR during the contraction or as a response to the contraction and to assess for changes in FHR.
7. When discrepancies in FHR are noted during auscultation, listen for longer periods to ID significant changes that may indicate need for another mode of FHR monitoring. |
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Term
| What is the recommended frequency of IA? |
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Definition
| recommended frequency of IA in low risk women is recommended every 15 minutes in the active phase of the first stage of labor and every 5 minutes in the second stage of labor. Other recommendations are every hour in the latent phase of first-stage labor, every 30 minutes in the active phase of first-stage labor, and every 15 minutes in the second stage of labor. The optimal frequency for IA in low risk women during labor has not been determined. |
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Term
| External mode of Electronic fetal monitoring (EFM) |
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Definition
FHR Ultrasound transducer: High-frequency sound waves reflect mechanical action of fetal heart; noninvasive; does not require rupture of membranes or cervical dilation; used during both antepartum and intrapartum periods.
Uterine Activity (UA) Tocotransducer: Monitors frequency and duration of contractions by means of pressure-sensing device applied to maternal abdomen; used during both antepartum and intrapartum periods. |
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Term
| Internal mode of Electronic fetal monitoring (EFM) |
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Definition
Spiral electrode: Converts fetal ECG as obtained from presenting part to FHR via cardiotachometer; can be used only when membranes are ruptured and cervix is sufficiently dilated during intrapartum period; electrode penetrates into fetal presenting part by 1.5mm and must be attached securely to ensure good signal.
Intrauterine pressure catheter (IUPC): Monitors frequency, duration, and intensity of contractions; two types of IUPCs: fluid-filled system and solid catheter; both measure intrauterine pressure at catheter tip and convert pressure into millimeters of mercury on uterine activity panel of strip chart; both can be used only when membranes are ruptured and cervix is sufficiently dilated during intrapartum period. |
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Term
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Definition
| The average rate during a 10-minute segment that excludes periodic or episodic changes, periods of marked variability, and segments of the baseline that differ by more than 25 beats/min. There must be at least 2 minutes of interpretable baseline data in a 10-minute segment of tracing to determine the baseline FHR. |
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Term
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Definition
| Tachycardia is a baseline FHR greater than 160 beats/min for 10 minutes or longer. It can be considered an early sign of fetal hypoxemia. |
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Term
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Definition
| Bradycardia is a baseline FHR less than 110 beats/min for 10 minutes or longer. Bradycardia is often caused by some type of fetal cardiac problem such as structural defects involving the pacemakers or conduction system or fetal heart failure. |
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Term
| Define variability in FHR |
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Definition
| Variability of the FHR can be described as irregular waves or fluctuations in the baseline FHR of two cycles per minute or greater. It is a characteristic of the baseline FHR and does not include accelerations or decelerations of the FHR. It is quantified in beats per minute and is measured from the peak to the trough of a single cycle. Four possible categories of variability have been identified: absent, minimal, moderate, and marked. |
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Term
| Define Acceleration of FHR |
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Definition
| a visually apparent, abrupt (onset to peak less than 30 seconds) increase in FHR above the baseline rate. The peak is at least 15 beats/min above the baseline, and the acceleration lasts 15 seconds or more, with the return to baseline less than 2 minutes from the beginning of the acceleration. |
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Term
| Define early fetal FHR deceleration |
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Definition
| Early deceleration of the FHR is a visually apparent, gradual (onset to lowest point ≥30 seconds) decrease in and return to baseline FHR associated with UCs. It is thought to be caused by transient fetal head compression and is considered a normal and benign finding. |
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Term
| Causes of FHR acceleration |
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Definition
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Term
| Define Late FHR deceleration |
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Definition
| Late deceleration of the FHR is a visually apparent, gradual (onset to lowest point ≥30 seconds) decrease in and return to baseline FHR associated with UCs. The deceleration begins after the contraction has started, and the lowest point of the deceleration occurs after the peak of the contraction. The deceleration usually does not return to baseline until after the contraction is over. Traditionally late decelerations have been attributed to uteroplacental insufficiency. |
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Term
| Define variable FHR deceleration |
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Definition
| Variable deceleration of the FHR is defined as a visually abrupt (onset to lowest point <30 seconds) and apparent decrease in FHR below the baseline. The decrease is at least 15 beats/min or more below the baseline, lasts at least 15 seconds, and returns to baseline in less than 2 minutes from the time of onset. Variable decelerations occur any time during the UC phase and are caused by compression of the umbilical cord. |
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Term
| Interventions for late FHR deceleration |
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Definition
The usual priority is as follows:
1. Change maternal position (lateral).
2. Correct maternal hypotension by elevating legs.
3. Increase rate of maintenance intravenous solution.
4. Palpate uterus to assess for tachysystole.
5. Discontinue oxytocin if infusing.
6. Administer oxygen at 8 to 10 L/min by nonrebreather face mask.
7. Notify physician or nurse-midwife.
8. Consider internal monitoring for more accurate fetal and uterine assessment.
9. Assist with birth (cesarean or vaginal assisted) if pattern cannot be corrected. |
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Term
| Define prolonged FHR deceleration |
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Definition
prolonged deceleration is a visually apparent decrease in FHR of at least 15 beats/min below the baseline and lasting more than 2 minutes but less than 10 minutes. Prolonged decelerations are caused when the mechanisms responsible for late or variable decelerations last for an extended period (more than 2 minutes). Examples of conditions that can cause an interruption in the fetal oxygen supply long enough to produce a prolonged deceleration include maternal hypotension, uterine tachysystole or rupture, extreme placental insufficiency, and prolonged cord compression or prolapse.
Nurses should notify the physician immediately and initiate treatment of abnormal patterns when they see a prolonged deceleration. |
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Term
| Interventions for Variable decelerations |
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Definition
The usual priority is as follows:
1. Change maternal position (side to side, knee chest).
2. Discontinue oxytocin if infusing.
3. Administer oxygen at 8 to 10 L/min by nonrebreather face mask.
4. Notify physician or nurse-midwife.
5. Assist with vaginal or speculum examination to assess for cord prolapse.
6. Assist with amnioinfusion if ordered.
7. Assist with birth (vaginal assisted or cesarean) if pattern cannot be corrected. |
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Term
| The five essential components of the FHR tracing that must be evaluated regularly |
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Definition
baseline rate
baseline variability
accelerations
decelerations
changes or trends over time |
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Term
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Definition
| Amnioinfusion is infusion of room-temperature isotonic fluid (normal saline or lactated Ringer’s) into the uterine cavity if the volume of amniotic fluid is low. Without the buffer of amniotic fluid, the umbilical cord can easily become compressed during contractions or fetal movement. The purpose of amnioinfusion is to relieve cord compression that results in variable decelerations and transient fetal hypoxemia by restoring the amniotic fluid volume to a normal or near-normal level. |
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Term
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Definition
| Tocolysis (relaxation of the uterus) can be achieved through the administration of drugs that inhibit UCs. Tocolysis improves blood flow through the placenta by inhibiting UCs. |
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