Fetal Heart Rate Monitoring

Prepared for Pass the Shift (owner: Kristina, RN). Always follow your facility’s protocols, provider orders, and current references.

1. Overview and Physiology

The fetal heart rate (FHR) tracing is a window into fetal oxygenation. Oxygen travels from the parent’s lungs → blood → uterus → placenta → umbilical cord → fetus. Anything that interrupts that chain (low maternal BP, too-strong contractions, cord compression, placental problems) can show up on the strip.

• Sympathetic vs. parasympathetic tone in the fetal brain constantly nudge the heart rate up and down. That “wiggle” is variability, and it is the best sign that the fetal brain is getting oxygen right now.
• Contractions briefly reduce blood flow into the placenta. A healthy fetus with good reserve tolerates this.

Monitoring methods

Method	How	Notes
Intermittent auscultation	Doppler at set intervals	For low-risk labor per protocol
External (EFM)	Ultrasound transducer for FHR; toco for contractions	Toco shows timing, not true strength
Internal	Fetal scalp electrode (FSE) for FHR; IUPC for contraction strength in mmHg	Requires ruptured membranes and a dilated cervix. Avoid FSE with HIV, active herpes, or face presentation; follow protocol

2. Reading the Strip — The Systematic Approach

Use “DR C BRAVADO”: Determine Risk, Contractions, Baseline RAte, Variability, Accelerations, Decelerations, Overall assessment.

Contractions: frequency (start of one to start of the next), duration, intensity, resting tone. Tachysystole = more than 5 contractions in 10 minutes, averaged over 30 minutes.

Baseline FHR (mean rate over 10 minutes, rounded to 5 bpm, excluding accels/decels):

Category	Rate	Common causes
Normal	110–160 bpm
Bradycardia	< 110 bpm for ≥ 10 min	Hypoxia, cord prolapse, maternal hypotension, uterine rupture, fetal heart block; post-term fetus may run low-normal
Tachycardia	> 160 bpm for ≥ 10 min	Maternal fever/infection (Chorioamnionitis (intraamniotic infection)), fetal hypoxia (early), maternal dehydration, terbutaline/meds, maternal hyperthyroidism, fetal anemia

Variability (amplitude of the wiggle):

Type	Amplitude	Meaning
Absent	Undetectable	Ominous with recurrent decels
Minimal	≤ 5 bpm	Sleep cycle (usually < 40 min), opioids, magnesium; or hypoxia/acidemia
Moderate	6–25 bpm	Reassuring — rules out acidemia at that moment
Marked	> 25 bpm	Uncertain; may be early hypoxia
Sinusoidal	Smooth, regular sine wave	Severe fetal anemia (e.g., Rh disease, fetomaternal hemorrhage); emergency

Accelerations: abrupt rise ≥ 15 bpm for ≥ 15 seconds (≥ 32 weeks) or ≥ 10 × 10 (< 32 weeks). Accelerations = a well-oxygenated fetus.

3. Decelerations — VEAL CHOP

Decel	Shape and timing	Cause	Nursing action
Variable	Abrupt drop (≤ 30 s to nadir); V/U/W shape; any timing	Cord compression	Reposition (side to side, knee-chest); if cord prolapse suspected, see emergencies; Amnioinfusion may be ordered
Early	Gradual; mirrors the contraction (nadir at peak)	Head compression	None needed — benign. Document
Accelerations	Abrupt rise	OK / oxygenated	None
Late	Gradual; begins after the contraction starts, nadir after the peak	Placental insufficiency (uteroplacental)	Intrauterine resuscitation (below); notify the provider

Prolonged deceleration: ≥ 15 bpm below baseline lasting 2–10 minutes. Treat like a late/variable emergency and call for help.

Recurrent = with ≥ 50% of contractions in 20 minutes.

4. Three-Tier Category System (NICHD/ACOG)

Category	Features	Response
I — Normal	Baseline 110–160, moderate variability, no late/variable decels; early decels and accels may be present	Routine monitoring
II — Indeterminate	Anything not I or III (e.g., tachycardia, minimal variability, recurrent variables with moderate variability, prolonged decel)	Evaluate, intrauterine resuscitation, closer surveillance, notify provider
III — Abnormal	Absent variability with recurrent late decels, recurrent variable decels, or bradycardia; or a sinusoidal pattern	Immediate resuscitation and prepare for expedited birth

5. Priority Nursing Interventions — Intrauterine Resuscitation

For late decels, recurrent variables, prolonged decels, tachysystole, or a Category II/III tracing:

1. Stop or reduce oxytocin (often the first step if it’s running)
2. Reposition — lateral (left or right); hands-and-knees for variables
3. IV fluid bolus (lactated Ringer’s) as ordered — treats maternal hypotension, especially after an epidural
4. Correct maternal hypotension (vasopressor such as ephedrine/phenylephrine per order)
5. Notify the provider; stay at the bedside; document
6. Tocolytic (e.g., terbutaline SubQ) for tachysystole as ordered
7. Oxygen — no longer routine for every tracing; give per order/protocol (e.g., when the parent is hypoxic)
8. Check the cervix if prolapse or rapid descent is suspected; prepare for operative birth if not resolved

6. Antepartum Testing

Test	Reassuring result	Notes
Nonstress test (NST)	Reactive: ≥ 2 accelerations in 20 min (15×15 at ≥ 32 weeks)	Nonreactive → extend to 40 min, vibroacoustic stimulation, or BPP
Contraction stress test	Negative (no late decels with 3 contractions in 10 min)	“Negative is good.” Positive = late decels with ≥ 50% of contractions
Biophysical profile (BPP)	8–10/10	NST + 4 ultrasound items: breathing, movement, tone, amniotic fluid (2 points each)
Fetal kick counts	Commonly ≥ 10 movements in 2 hours	Teach to call for decreased movement — a change from baseline matters most

7. Medications That Affect the Strip

• Opioids, magnesium sulfate: decreased variability (expected, but still evaluate)
• Terbutaline: fetal and maternal tachycardia
• Oxytocin: tachysystole → late decels
• Epidural/spinal: maternal hypotension → late decels or bradycardia
• Maternal fever / acetaminophen: fever causes tachycardia; treat the fever per order

8. Emergencies

Umbilical cord prolapse (cord slips past the presenting part, often after rupture of membranes with a high presenting part):

1. Call for help; do not leave
2. Gloved hand in the vagina to lift the presenting part off the cord; keep it there
3. Knee-chest or Trendelenburg position
4. Don’t push the cord back. If the cord is outside, cover with sterile saline-moistened gauze
5. Stop oxytocin, oxygen per protocol, prepare for emergency cesarean

Uterine rupture: sudden abnormal FHR (often prolonged decel/bradycardia), loss of station, severe pain, signs of shock; risk ↑ with prior uterine scar. Emergency surgery.

9. Memory Aids

• VEAL CHOP: Variable–Cord, Early–Head, Accel–OK, Late–Placenta
• Late decels: “Late is Lethal-ish” — placenta isn’t keeping up
• “Moderate variability is my best friend”
• Intrauterine resuscitation, “LION”: Left/lateral side, IV fluids, Oxytocin off (and oxygen per protocol), Notify provider
• NST: “Reactive is Right”; CST: “Negative is Nice”

10. NCLEX-Style Practice Questions

1. A laboring client on oxytocin has recurrent late decelerations with minimal variability. What is the nurse’s first action?

A. Increase the IV fluid rate only
B. Discontinue the oxytocin infusion
C. Apply a fetal scalp electrode
D. Document and continue to monitor

Answer: B. Late decels mean uteroplacental insufficiency; oxytocin-driven contractions further reduce placental flow. Stop oxytocin first, then reposition, bolus fluids, and notify the provider. A fluid bolus helps but doesn’t remove the cause. Monitoring alone (D) is unsafe.

2. The nurse notes FHR decelerations that start and end with each contraction, with the lowest point at the contraction’s peak. Baseline is 140 with moderate variability. What should the nurse do?

A. Turn the client to her left side and give oxygen
B. Prepare for emergency cesarean birth
C. Continue routine monitoring and document
D. Perform a vaginal exam to check for cord prolapse

Answer: C. These are early decelerations from fetal head compression, a benign finding. With a normal baseline and moderate variability, this is a Category I tracing.

3. After spontaneous rupture of membranes, the FHR drops abruptly to 70 bpm and the nurse sees the umbilical cord at the vaginal opening. Which action is the priority?

A. Gently push the cord back into the vagina
B. Place a gloved hand in the vagina and lift the presenting part off the cord
C. Prepare the client for an ultrasound
D. Encourage the client to push with the next contraction

Answer: B. Relieving pressure on the cord restores fetal blood flow. Also call for help and position the client knee-chest or Trendelenburg while preparing for emergency birth. Never reposition the cord (A).

4. A client at 34 weeks has an NST with three accelerations of 15 bpm lasting 15–20 seconds in 20 minutes. How should the nurse interpret this?

A. Nonreactive; schedule a contraction stress test
B. Reactive; a reassuring result
C. Positive; notify the provider immediately
D. Equivocal; repeat in one hour

Answer: B. A reactive NST has at least 2 qualifying accelerations in 20 minutes, which shows intact fetal oxygenation.

5. A laboring client has a temperature of 38.6 °C (101.5 °F). The FHR baseline has risen from 140 to 175 bpm over the past hour. The nurse recognizes which is the most likely cause?

A. Head compression
B. Maternal infection such as chorioamnionitis
C. Normal response to a cervical exam
D. Fetal sleep cycle

Answer: B. Maternal fever is a leading cause of fetal tachycardia. Report it, expect cultures/antibiotics and antipyretics per order, and watch for other signs (uterine tenderness, foul fluid). Sleep cycles reduce variability, not raise the rate.

References

American College of Obstetricians and Gynecologists. (2009, reaffirmed). Intrapartum fetal heart rate monitoring: Nomenclature, interpretation, and general management principles (Practice Bulletin No. 106). Obstetrics & Gynecology, 114(1), 192–202. https://doi.org/10.1097/AOG.0b013e3181aef106

National Council of State Boards of Nursing. (2026). 2026 NCLEX-RN test plan. https://www.nclex.com/test-plans.page

Sung, S., & Vadakekut, E. S. (2026). Fetal heart rate tracing: Assessment and clinical interpretation. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK546627/