What is CTG variability?
What is CTG variability?
Variability. Baseline variability refers to the variation of fetal heart rate from one beat to the next.
What is normal fetal variability?
The normal FHR tracing include baseline rate between 110-160 beats per minute (bpm), moderate variability (6-25 bpm), presence of accelerations and no decelerations.
What is baseline variability?
Baseline variability is defined as fluctuations in the fetal heart rate of more than 2 cycles per minute. No distinction is made between short-term variability (or beat-to-beat variability or R-R wave period differences in the electrocardiogram) and long-term variability.
What does marked fetal variability mean?
Marked variability in FHR patterns was defined as fluctuations in FHR amplitude of > 25 beats per minute based on 10-minute epochs, excluding accelerations and decelerations from baseline.
How do you interpret CTG variability?
Normal antenatal CTG trace: The normal antenatal CTG is associated with a low probability of fetal compromise and has the following features: Baseline fetal heart rate (FHR) is between 110-160 bpm • Variability of FHR is between 5-25 bpm • Decelerations are absent or early • Accelerations x2 within 20 minutes.
What is short term variability?
Short term variability (STV) is used to measure the cardiac autonomic control. This is an average of the absolute values of the differences between adjacent RR intervals in the electrocardiogram (Van Ravenswaaij-Arts et al., 1993).
What causes reduced variability?
Reduced variability can occur due to central nervous system hypoxia/acidosis and resulting decreased sympathetic and parasympathetic activity, but it can also be due to previous cerebral injury [23], infection, administration of central nervous system depressants or parasympathetic blockers.
What is variability in labor and delivery?
The normal fetal heart rate baseline is from 120 to 160 BPM and has both short and long-term “variability.” Short-Term variability means that from one moment to the next, the fetal heart speeds up slightly and then slows down slightly, usually with a range of 3-5 BPM from the baseline.
What causes decreased variability?
17 Fetal hypoxia, congenital heart anomalies and fetal tachycardia also cause decreased variability. Beat-to-beat or short-term variability is the oscillation of the FHR around the baseline in amplitude of 5 to 10 bpm.
What is the definition of marked variability?
Marked variability is defined by a fluctu- ation grade greater than 25 beats from peak to trough, and. has been used to describe FHR patterns since the early use. of fetal ECG in the 1970s.
What is suspicious CTG?
8.3 Suspicious If the CTG trace is categorised as suspicious: • Correct any underlying causes, such as hypotension or uterine hyperstimulation. • Perform a full set of maternal observations. • Start one or more conservative measures. • Inform an obstetrician or a senior midwife .
What does variability mean in fetal heart rate?
Variability is defined as fluctuations in the FHR baseline of 2 cycles per minute or greater, with irregular amplitude and inconstant frequency. These fluctuations are visually quantitated as the amplitude of the peak to trough in beats per minute, as shown in Table 1.
What causes increased variability in the CTG-guideline?
Increased Variability (Saltatory Pattern) a bandwidth value exceeding 25 bpm lasting more than 30 minutes. The pathophysiology of this pattern is incompletely understood, but it may be seen linked with recurrent decelerations, when hypoxia/acidosis evolves very rapidly. It is presumed to be caused by fetal autonomic instability/hyperactivity.
Is there a guideline for fetal CTG interpretation?
Disclaimer This guideline describes fetal monitoring using physiology-based CTG interpretation.
What does it mean when your CTG does not show acceleration?
The absence of accelerations with an otherwise normal CTG is of uncertain significance. Decelerations are an abrupt decrease in the baseline fetal heart rate of greater than 15 bpm for greater than 15 seconds. Fetal heart rate is controlled by the autonomic and somatic nervous system.
What does CTG stand for in medical terms?
If it is difficult to categorise or interpret a CTG trace, obtain a review by a senior midwife or a senior obstetrician. The presence of fetal heart rate accelerations, even with reduced baseline variability, is generally a sign that the baby is healthy. Abbreviation: CTG, cardiotocography.