Fetal Heart Rate Patterns and Decelerations
What it is
Electronic fetal monitoring shows how well the fetus is oxygenated and how its autonomic nervous system controls the heart rate. Moderate variability is the most reliable sign that the fetus is well oxygenated and not acidemic. The shape and timing of a deceleration reveal its cause: early decelerations come from head compression, variable decelerations from cord compression, and late decelerations from uteroplacental insufficiency. Tracings are classified by the NICHD three-tier system.
What the NCLEX focuses on
- Baseline 110 to 160/min, read over 10 minutes; tachycardia suggests maternal fever, intraamniotic infection or fetal hypoxia; bradycardia suggests hypoxia, cord prolapse or maternal hypotension.
- Variability: absent, minimal (5/min or less), moderate (6 to 25/min), marked (more than 25/min); opioids and fetal sleep reduce it temporarily.
- VEAL CHOP: Variable = Cord compression, Early = Head compression, Accelerations = OK, Late = Placental insufficiency.
- Early decelerations are gradual and mirror the contraction; they are benign and need no intervention.
- Late decelerations are gradual with the lowest point after the contraction peak; recurrent lates with minimal or absent variability are ominous.
- Variable decelerations are abrupt (under 30 seconds to the lowest point), V- or U-shaped, and occur with oligohydramnios or after rupture of membranes.
- Category III: absent variability with recurrent late or variable decelerations or bradycardia, or a sinusoidal pattern (severe fetal anemia).
Priority nursing actions
- Stop the oxytocin infusion if one is running.
- Turn the client to a lateral position to relieve aortocaval and cord compression.
- Give a prescribed IV bolus of non-dextrose isotonic fluid and correct maternal hypotension.
- Give oxygen per protocol when maternal hypoxemia is present.
- Notify the provider, document the response, and prepare for amnioinfusion (recurrent variables) or expedited birth (persistent Category III).
- With sudden variables or bradycardia after membranes rupture, check for cord prolapse.
Numbers to know
| Feature | Normal or definition | Why it matters |
|---|---|---|
| Baseline | 110 to 160/min | Abnormal rates point to infection, hypoxia or hypotension |
| Moderate variability | 6 to 25/min | Most reliable sign of fetal oxygenation |
| Acceleration at 32 weeks or more | 15/min above baseline for 15 seconds | Reactive and reassuring |
| Variable deceleration | Under 30 seconds from onset to lowest point | Abrupt shape means cord compression |
| Early or late deceleration | 30 seconds or more from onset to lowest point | Timing with the contraction separates benign from ominous |
| Prolonged deceleration | 2 minutes or more but under 10 minutes | Requires immediate intrauterine resuscitation |
| Tachysystole | More than 5 contractions in 10 minutes, averaged over 30 minutes | Stop oxytocin; uterine rest restores placental flow |
Common exam traps
- Choosing oxygen, position change or cesarean preparation for early decelerations: wrong because head compression is benign; continue routine monitoring.
- Choosing to increase oxytocin with recurrent late decelerations: wrong because contractions are reducing placental flow; stop the infusion.
- Choosing emergency cesarean when the monitor suddenly reads 88/min during pushing: wrong because it can be recording the maternal pulse; compare maternal pulse with the fetal rate first.
- Choosing naloxone for minimal variability shortly after an IV opioid with no decelerations: wrong because this is an expected, temporary drug effect.
- Choosing supine positioning during resuscitation: wrong because the uterus compresses the vena cava and reduces placental perfusion.
What to teach
- Explain that position changes and IV fluids improve blood flow to the baby and are common, not a sign of emergency.
- A low-risk client can walk and shower with intermittent auscultation instead of continuous monitoring.
- Report a gush of fluid or a feeling of something in the vagina immediately (possible cord prolapse).
Try 2 NCLEX-style questions on this topic
From the NCLEXPace question bank. Pick your answers, then check them inside NCLEXPace.
The nurse reviews fetal heart rate tracings for a client whose amniotic fluid index is 4 cm. For each finding, indicate whether it most likely results from umbilical cord compression or from another cause.
For each deceleration pattern, indicate whether it results from cord compression or from another cause.
| Umbilical cord compression | Another cause | |
|---|---|---|
| Gradual dip that begins and ends with each contraction and mirrors its shape | ||
| Abrupt V-shaped drop to 80 beats per minute lasting 40 seconds, occurring at different times relative to contractions | ||
| Sustained drop to 70 beats per minute lasting 4 minutes immediately after a gush of fluid | ||
| Gradual dip whose lowest point occurs after the contraction peak | ||
| Abrupt drop with a sharp fall and rapid return that varies in depth from one contraction to the next |
The nurse reviews a 30-minute tracing for a client on oxytocin and counts 7 contractions in each 10-minute window, each lasting 70 seconds, with a resting tone between contractions of 25 mm Hg by intrauterine pressure catheter. The fetal heart rate shows recurrent late decelerations. Which action should the nurse take first?
Select the best answer.
- A. Discontinue the oxytocin infusion
- B. Prepare the equipment for an amnioinfusion to improve fetal oxygenation while the oxytocin infusion continues
- C. Increase the oxytocin infusion gradually to shorten the remaining labor and reduce the duration of fetal exposure to the abnormal tracing
- D. Document the contraction frequency and recurrent late decelerations, then continue the current oxytocin rate while observing for spontaneous improvement
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Fetal Heart Tracings: VEAL CHOP Explained Like a Nurse ThinksCord Prolapse, Abruption, Previa and Postpartum Hemorrhage: First ActionsMore tips on Maternal & Newborn
Prenatal Care: Labs, Fundal Height and Danger SignsDate the pregnancy, time the routine prenatal labs, interpret fundal height, and teach the danger signs a pregnant client reports at once.Postpartum Hemorrhage: Recognize Early, Act FastSpot hemorrhage before the blood pressure falls, firm a boggy uterus, empty the bladder, and give uterotonics within their contraindications.Newborn Assessment: Apgar and the First HoursScore the Apgar, know normal newborn vital signs and findings, and give first-hours care: warmth, glucose, vitamin K, eye care and security.Sources
- Macones GA, Hankins GDV, Spong CY, Hauth J, Moore T. The 2008 National Institute of Child Health and Human Development workshop report on electronic fetal monitoring: update on definitions, interpretation, and research guidelines. Obstet Gynecol. 2008;112(3):661-666.
- American College of Obstetricians and Gynecologists. Practice Bulletin No. 106: Intrapartum fetal heart rate monitoring: nomenclature, interpretation, and general management principles. Obstet Gynecol. 2009;114(1):192-202.
- American College of Obstetricians and Gynecologists. Practice Bulletin No. 116: Management of intrapartum fetal heart rate tracings. Obstet Gynecol. 2010;116(5):1232-1240.
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