Questions and Answers
What is the normal FHR range?
Baseline FHR bradycardia is defined as a baseline FHR below 160 bpm for at least 10 minutes.
True
What are some maternal causes of baseline FHR tachycardia?
Fever/infection, dehydration, hyperthyroidism, anemia, anxiety, smoking, medication response, adrenaline.
What reflects the status of the CNS in FHR variability?
Signup and view all the answers
Absent FHR variability is defined as an amplitude range that is ______.
Signup and view all the answers
What is considered moderate baseline FHR variability?
Signup and view all the answers
What does an acceleration in FHR indicate?
Signup and view all the answers
Changes in FHR can be periodic or episodic.
Signup and view all the answers
What is considered a normal response of a healthy fetus during labor?
Signup and view all the answers
Gray area in FHR indicates a ______ decrease that lasts for at least 30 seconds.
Signup and view all the answers
Intermittent decelerations occur with more than 50% of uterine contractions.
Signup and view all the answers
Study Notes
Baseline FHR
- Normal fetal heart rate (FHR) ranges from 110-160 bpm.
- Baseline determined by mean FHR over a 10-minute period, excluding accelerations or decelerations.
- At least 2 minutes of identifiable baseline segments required for determination; otherwise, it is indeterminate.
Baseline FHR Bradycardia
- Bradycardia is identified when baseline FHR is below 110 bpm for at least 10 minutes.
- Indicates increased sympathetic nervous system (SNS) tone or decreased parasympathetic nervous system (PNS) tone.
- Requires close monitoring and evaluation.
Causes of Baseline FHR Tachycardia
- Maternal factors: fever, infection, dehydration, hyperthyroidism, anemia, anxiety, smoking, certain medications, and adrenaline.
- Fetal factors: prolonged activity, chronic hypoxemia, chorioamnionitis, cardiac issues, and compensatory responses to transient hypoxemia.
Baseline FHR Variability
- Variability indicates fluctuations in baseline FHR, measured over a 10-minute interval.
- Reflects central nervous system (CNS) status.
- Evaluated using peak-to-trough amplitude while excluding sinusoidal patterns.
FHR Variability Classifications
- Absent: undetectable amplitude range.
- Minimal: detectable but ≤ 5 bpm amplitude range.
- Moderate (reassuring): amplitude range of 6-25 bpm.
- Marked: amplitude range exceeding 25 bpm.
Causes of Minimal Baseline FHR Variability
- Maternal influences: CNS depressants, alcohol, several specific pain medications, and opioids.
- Fetal influences: sleep cycles, CNS anomalies, hypoxia, cardiac defects, and vagal stimulation.
Moderate Baseline FHR Variability
- Indicates good CNS control over the FHR and sufficient oxygenation levels to the fetus.
Accelerations
- Defined as an abrupt increase in FHR, occurring within 30 seconds, with a peak of at least 15 bpm lasting for 15 seconds or more.
- Before 32 weeks gestation, accelerations are defined as a peak of at least 10 bpm lasting 10 seconds or more.
Causes of FHR Changes
- Periodic or episodic changes can result from decreased oxygenation, umbilical cord compression, and uterine contraction pressure on the fetal head.
- Healthy fetuses alternate between quiet and active sleep, impacting FHR variability.
Components of a Normal FHR Tracing
- Baseline must remain within 110-160 bpm.
- Moderate variability is reassuring.
- Presence of accelerations is a positive sign.
- Absence of decelerations is also reassuring.
- Uterine contraction patterns must be monitored.
5 Steps to Interpreting FHR Tracing
- Measure baseline FHR over a 10-minute window.
- Assess variability and categorize it as absent, minimal, moderate, or marked.
- Analyze the presence of accelerations, reassuring with active fetal movement.
- Note the absence of decelerations as a positive indicator.
- Review uterine contraction patterns in relation to FHR changes.
Periodic FHR Pattern
- FHR patterns that are directly linked to uterine contractions.
Episodic FHR Pattern
- FHR patterns that occur independently from uterine contractions.
Deceleration
- Characterized by a decrease in FHR of at least 15 bpm, lasting at least half of the uterine contractions observed in any 20-minute segment.
Intermittent Decelerations
- Occur with less than 50% of uterine contractions within a 20-minute timeframe.
Gradual FHR Decrease
- Defined by a reduction from the onset to the nadir (lowest point) of FHR, taking longer than 30 seconds.
Early Decelerations
- Normal fetal response to labor as pressure from the cervix is transmitted to the fetal head during contractions.
- Occurs concurrently with uterine contractions and requires a normal FHR baseline with moderate variability.
- Gradual decrease and return of FHR, typically reflecting contraction timing.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge of fetal heart rate (FHR) terminology and definitions with these flashcards. This quiz covers key concepts like baseline FHR and bradycardia, providing a solid foundation for understanding FHR patterns. Ideal for nursing and midwifery students.