What is fetal heart rate monitoring and VEAL CHOP MINE?

VEAL CHOP MINE is a mnemonic used during intrapartum (labor) fetal heart rate monitoring. “VEAL” is the acronym for fetal heart rate pattern, “CHOP” stands for the causes of it, and the “MINE” represents the nursing interventions.

The goal of fetal heart rate monitoring during labor is:

• to identify the well-being of the fetus
• to identify signs of fetal compromises, such as fetal hypoxia
• to implement interventions as soon as possible to ensure the safe delivery of the baby

Severe hypoxia in labor along with metabolic acidosis can cause fetal organ damage or fetal death. Therefore, as nurses, we must know what to look for and when to take action.

Here, in this article, we’ll discuss fetal heart rate monitoring, mnemonic “VEAL CHOP MINE” and its nursing interventions.

What is fetal heart rate monitoring?

Fetal heart rate (FHR) monitoring can be defined as the close observation of fetal behavior during the delivery.

Fetal heart rate assessment is the key tool for monitoring the status of the fetus during labor. It gives an indirect indication of the oxygen status of the fetus.

FHR monitoring is crucial during labor because of the frequent changes in intrauterine pressure with the contractions.

Additionally, even in normal deliveries fetus experience distress due to:

• Uterine contraction reduces uteroplacental circulation
• Uterine contraction affects intrauterine pressure
• Head compression affects the function of the vital brain centers

Methods of fetal heart rate monitoring

The fetal heart rate can be monitored either (1) intermittently or (2) continuously with an electronic device. Both the methods will be discussed in detail.

Another important thing to consider while assessing fetal heart rate is not to confuse FHR with the maternal heart rate.

To ensure that, palpate the mother’s radial pulse simultaneously while the FHR is being auscultated through the abdomen.

Nursing interventions during labor include:

• Observe for any change in maternal condition, such as ruptured membranes or the onset of bleeding.
• Assessing FHR every 30 minutes interval initially followed by 15 minutes intervals in the first stage.
• Assessing FHR every 5 minutes in the second stage.
• Assess FHR for 60 seconds before and immediately following a uterine contraction. From then on, unless there is a problem, listening for 30 seconds and multiplying the value by two is sufficient.

Location of fetal heart rate during intrapartum

The back of the fetus is where you’ll hear FHR most clearly. Use Leopold’s maneuvers to locate the back of the fetus.

In a cephalic presentation, the FHR is best heard in the lower quadrant of the mother’s abdomen.

In a breech presentation, it is heard at or above the level of the mother’s umbilicus.

As labor progresses, the FHR location will change accordingly as the fetus descends lower into the mother’s pelvis for the birthing process.

1. Intermittent auscultation

Intermittent fetal heart rate monitoring involves periodic auscultation of FHR using an ordinary stethoscope or a fetoscope or a hand-held Doppler. During the assessment, you’ll observe the fetal heart rate, rhythm, and intensity.

What to look for when you are monitoring FHR intermittently:

• Increase in fetal heart rate to over 160 bpm
• Decrease in fetal heart rate to less than 110 bpm
• Fetal heart rate takes a long time to come back to its normal rate after the contraction passes off
• Irregular rhythm

The Benefits of intermittent fetal heart rate monitoring include:

• can detect baseline fetal heart rate, rhythm, and changes from baseline
• mobility for the mother in the first stage of labor
• freedom of movements since she is not attached to a stationary electronic fetal monitoring device

The limitations of intermittent fetal heart rate monitoring include:

• Inability to detect variability and types of decelerations
• Any transient significant abnormality in between observations are likely to be overlooked
• Inherent human error
• Sometimes difficult to count the fetal heart rate during uterine contractions or in case of obesity or hydramnios

2. Continuous Electronic Fetal Monitoring

As the name states, it is continuously monitoring fetal behavior using an electronic device during labor. This Electronic Fetal Monitoring (EFM) is called Cardiotocography (CTG). It traces both the fetal heart rate, fetal movement, and uterine contractions on a graph paper.

This can be done either using invasive or non-invasive devices.

Non-invasive or external EMF

Non-invasive continuous motoring can be done externally by placing transducers on the mother’s tummy. A belt is used to secure these transducers.

The machine have two transducers. One is called toco-transducer. It records uterine contractions.

The other one is called an ultrasound transducer. And it records baseline FHR, long-term variability, accelerations, and decelerations.

Placement of non-invasive transducers

Toco-transducer – placed over the uterine fundus in the area of greatest contractility to monitor uterine contractions.

Ultrasound transducer – placed over mother’s abdomen in the midline between the umbilicus and the symphysis pubis.

The diaphragm of the ultrasound transducer is moved to either side of the abdomen to obtain a stronger sound.

Invasive or internal EMF

Invasive EMF is done by applying a spiral pointed scalp electrode to the fetal scalp after rupturing the membranes. Intrauterine pressure could be simultaneously measured by passing a catheter inside the uterine cavity.

The fetal spiral electrode is the most accurate method of detecting fetal heart characteristics and patterns because it involves directly receiving a signal from the fetus.

Invasive EMF is used for high risk mothers or fetuses.

Indication for Continuous Electronic Fetal Monitoring (EMF)

Continuous electronic fetal monitoring may be indicated due maternal or fetal conditions. It is listed below.

Maternal conditions include:

• Hypertension
• Previous cesarean delivery
• Induced labor
• Antepartum haemorrhage (APH)
• Premature rupture of membrane (PROM)

Fetal conditions include:

• Small fetus (IUGR)
• oligohydramnios
• multiple pregnancies
• abnormal FHR on auscultation

Benefits of electronic fetal monitoring include:

• Accurate monitoring of uterine contractions
• Significant improvement of perinatal mortality
• Can detect hypoxia early
• Significant reduction in intrapartum fetal death rate

Disadvantages of this method include:

• Interpretation is affected by intra- and interobserver error
• Due to errors of interpretation, the cesarean section rate may be increased
• Instruments are expensive and trained personnel are required to interpret a trace
• Mother has to be confined in bed

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Baseline Fetal Heart Rate (FHR)

The baseline fetal heart rate can be defined as the average heart rate of the fetus within a 10-minute period.

The baseline rate should be within the normal range. That is 110–160 beats per minute.

The most common abnormality in fetal heart rate are fetal bradycardia and fetal tachycardia.

Fetal Bradycardia

Fetal bradycardia is defined as a baseline fetal heart rate of less than 110 bpm and lasts longer than 10 minutes.

Causes of Fetal Bradycardia

• Occiput posterior or transverse presentations
• Prolonged cord compression
• Cord prolapse
• Anesthesis (epidural and spinal)
• Maternal seizures
• Rapid fetal descent
• Fetal acidosis
• Maternal hypotension
• Prolonged maternal hypoglycemia
• Fetal sepsis
• Anomalies such as fetal heart conduction defect
• Certain medications such as pethidine, antihypertensives (eg: methyldopa, propranolol), MgSO4

Fetal Tachycardia

Fetal tachycardia is defined as a baseline fetal heart rate more than 160 bpm and lasts longer than 10 minutes.

Causes of Fetal Tachycardia

• Drugs given to the mother such as, (i) β-sympathomimetic agents used to inhibit preterm labor (isoxsuprine, ritodrine); (ii) Vagolytic: atropine
• Fetal and/or maternal anemia
• Fetal and/or maternal infection
• Maternal dehydration
• Maternal anxiety
• Maternal hyperthyroidism
• Fetal hypoxia
• Fetal tachyarrhythmia
• Chorioamnionitis

How to interpret baseline fetal heart rate patterns?

Baseline fetal heart rate can be interpret as reassuring, non-reassuring or ominous signs.

Reassuring Signs	Non-reassuring Signs	Ominous Signs
a. Normal baseline (110–160 bpm)	a. Fetal tachycardia (>160 bpm)	a. Fetal tachycardia with loss of variability
b. Moderate bradycardia (100–120 bpm); good variability	b. Moderate bradycardia (100–110 bpm); lost variability	b. Prolonged marked bradycardia (<90 bpm)
c. Good beat-to-beat variability and fetal accelerations	c. Absent beat-to-beat variability	c. Severe variable decelerations (<70 bpm)
	d. Marked bradycardia (90–100 bpm)	d. Persistent late decelerations
	e. Moderate variable decelerations

Source

Baseline Fetal Heart Rate (FHR) Variability 

Baseline fetal heart rate variability refers to the fluctuation between fetal heartbeats. It doesn’t include accelerations and decelerations.

FHR Variability is a normal reflex that occurs as a result of the interaction between the parasympathetic and sympathetic nervous systems. It is an important clinical indicator that is predictive of fetal acid-base balance and cerebral tissue perfusion.

Baseline FHR variability can be short-term or long-term.

The presence of short-term variability is classified either as “present” or “absent”. And typically, it is an indication of a well-oxygenated and non-acidemic fetus.

Visually you can see the presence or absence of short-term variability.

To do that, evaluate the roughness or smoothness of the fetal heart tracing line. If roughness is present in the baseline, short-term variability is present. And it is absent if it is smooth.

Long-term variability is the waviness or rhythmic fluctuations. Its described as cycles per minute and the frequency of cycles is 3 to 6 per minute.

Long-term variability is categorized as:

• Absent – amplitude undetectable
• Mini­mal – amplitude is between 0 to 5 bpm
• Moderate – amplitude is between 6 to25 bpm
• Marked or salutatory – amplitude is above 25 bpm

Causes decreased FHR variability include:

• Fetal hypoxia
• Fetal acidosis
• Drugs such as opiates, benzodiazepines, methyldopa, and magnesium sulphate.
• Congenital abnormalities
• Fetal sleep: this is the most common cause and it should not last longer than 40 minutes.
• Prematurity: variability is reduced at earlier gestation (<28 weeks)
• Fetal tachycardia

How to interpret fetal heart variability?

Variability can be interpreted as reassuring, non-reassuring or abnormal. 

The variability is Reassuring, if it is between 5 – 25 bpm.

It is non-reassuring if:

• variability is less than 5 bpm for between 30-50 minutes, or
• more than 25 bpm for 15-25 minutes,

It is abnormal if:

• variability less than 5 bpm for more than 50 minutes
• more than 25 bpm for more than 25 minutes, or
• sinusoidal

Periodic Baseline Changes

Periodic baseline changes are temporary, recurrent changes made in response to a stimulus such as a contraction. The FHR shows a pattern of acceleration or deceleration in response to most stimuli.

Acceleration

Acceleration is defined as a momentary increase in fetal heart rate above the baseline.

Characteristics of acceleration

• visually apparent with elevations of FHR of at least 15 bpm above the baseline
• usually, last longer than 15 seconds but not for longer than 2 minutes
• prolonged acceleration is when it lasts longer than 2 minutes but less than 10 minutes
• if acceleration lasts more than 10 minutes, it is considered a change in baseline

Nursing Intervention

Acceleration is typically a sign of reassuring fetal status and no special nursing interventions is needed.

Early decelerations

Early deceleration is characterized by a gradual decrease and return to baseline of the FHR associated with a uterine contraction. 

The onset of early deceleration to nadir (lowest point) is usually more than or equal to 30 seconds. The nadir occurs at the same time as the peak of the contraction.

Causes for early deceleration is fetal head compression.

Nursing Intervention

Early decelerations are not indicative of fetal distress. Therefore, special nursing intervention is not required.

Late decelerations

Late decelerations can be defined as temporary decreases in FHR that occur after a contraction begins.

The FHR returns to normal only after the contraction has ended completely. Delayed timing of the deceleration occurs with the nadir of the uterine contraction.

The late deceleration is a sign of uteroplacental insufficiency and poor perfusion.

Causes for late deceleration include:

• maternal hypotension
• gestational hypertension
• placental aging secondary to diabetes
• post-maturity
• hyperstimulation via oxytocin infusion
• maternal smoking
• anemia
• cardiac disease

Nursing interventions

Nursing Intervention	Rationale
Turning the mother on her left side	Increases placental perfusion
Administer oxygen by mask	Increases fetal oxygenation
Increasing the IV fluid rate	Improves intravascular volume
Assessing mother for any underlying contributing causes	To identify and address underlying causes
Provide reassurance that interventions are to effect pattern change	Helps to reduce mental stress and anxiety

Additional nursing interventions include:

• informing the primary healthcare provider about pattern change
• reducing or stopping the Oxytocin drip
• accurate documentation

Variable decelerations

Variable deceleration is defined as an abrupt decrease of FHR from the onset of the deceleration to the beginning of the FHR nadir of <30 seconds.

The decrease in FHR is 15bpm or more. And lasts ≥ 15 seconds and less than 2 minutes.

The shape of variable decelerations may be U, V, or W, or they may not resemble other patterns.

It becomes a non-reassuring sign if:

• FHR decreases to less than 60 bpm
• persists at that level for at least 60 seconds
• repetitive decrease of FHR

Cause for variable deceleration

Cord compression

Nursing interventions

Nursing Intervention	Rationale
Reposition the mother	To relieve compression on the cord
Administer oxygen by mask	Increases fetal oxygenation
Increasing the IV fluid rate	Improves intravascular volume
Assessing mother for any underlying contributing causes	To identify and address underlying causes
Provide reassurance that interventions are to effect pattern change	Helps to reduce mental stress and anxiety

Additional nursing interventions same as the late deceleration interventions.

“VEAL CHOP MINE” in nursing

In nursing “VEAL CHOP MINE” used as an acronym to remember fetal heart rate variability and patterns during intrapartum monitoring.

The first word “VEAL” denotes patterns of fetal heart rate. Secondly, the word “CHOP” represents the cause for these pattern variations. Finally, “MINE” is for the nursing interventions required as per assessment findings.

VEAL CHOP MINE is further described in the table below.

Pattern	Cause	Nursing Intervention
V = Variable decelerations	C = Cord compression	M = Movement (Repositioning the mother)
E = Early deceleration	H = Head compression	I = Identify labor progress
A = Accelerations	O = Okay	N = No special intervention is needed
L = Late decelerations	P = Placental insufficiency	E = Emergency action is required to deliver the baby

Additional Sources

American College of Obstetricians and Gynecologists

National Institutes of Health (NIH)

Reference

Konar, H. (2015). DC Dutta’s textbook of obstetrics (8th ed). JP Brothers Medical.