Cardiotocography (CTG) is a check-up that is generally done during the pregnancy’s third trimester. The purpose of this test is to check if the heartbeats of your baby are at a regular rate and changeability (Mathew, 2012, par.1). In general, a baby's heart rate is 110 to 160 beats for each minute; in addition, it amplifies whenever there is a movement of the baby. Examining that the heart rate of the baby responds to its actions is another way of indirectly recognizing if it accesses sufficient oxygen while in the placenta. This examination also checks how the heart rate of the baby is swayed by the mother’s contractions (Mathew, 2012, par.1).
During the third trimester of a mother and she is not in labor, the check-up measures the mothers Braxton Hicks contractions. One may not be aware of them, but these Braxton Hicks contractions are simple contractions that the uterus gets in preparation of labor. Mathew (2012, par. 2) goes ahead and says that a CTG taken in the third trimester is in other words called a non-stress test, since the baby does not undergo the stress of labor.
The doctor tends to ask for the CTG during the third trimester if the mother feels that the baby has slowed down the movements or they have become irregular and if there are suspicions in regards to problems associated with the placenta that may limit blood circulation to the baby. In addition, in case the mother may be expecting twins, low levels of amniotic fluids or if there is a case of hypertension or diabetes in the mother.
To take this test, two monitors are belt-like fastened to the tummy of the mother. One of the monitor takes the measurements of the baby’s heart rate, while the other measures the contractions of the mother’s uterus. During this test, it is recommended either to be seated or laid down. The test last for 20 to 60 minutes (Mathew, 2012, par.4).
These monitors are sensors called transducers. The first one is known as a fetal heart transducer that is placed in a position that the feta’s heart is best taken notice of using a Doppler sonicade or otherwise it could be positioned on the head of the fetal after the cervix makes it easier to access. This transducer helps the mother to realize how much progress she is or is not making in pushing. It is also good to both the relatives and the doctor, since they can also see the progress.
The second transducer is known as the uterine pressure transducer. It is positioned over the fundus of the uterus. Though it is referred to as the uterine pressure, it takes into account the pressure of the wall found in the abdomen. As much as contrasts amid contraction are founded on the analysis, the exact contraction is not actually reflected. Someone who has experience in the field, for example, a midwife is the one who best measures it (Leach, 2012, par.3).
This test results into either being reactive or non-reactive. A test result that is reactive shows that the baby’s heart rate boosts in the projected way after each one of its movements. A result that is non-reactive is not necessarily an indication of a setback. The baby could only have been sleeping during the test. The doctor may carry out the test again after the mother makes some movements or with the use of a fetal acoustic stimulator, that wakens the baby. If the result is the same (non-reactive), the doctor may then recommend for an additional test, like after an hour (Mathew, 2012, par. 5).
The CTG test may also be carried out in the course of labor when there is a need for the baby’s constant monitoring. If the doctor recommends a Syntocinon drip to help in labor induction or the speeding up of labor, one generally gets a CTG. Syntocinon is an artificial oxytocin, a type of hormone present during a labor, which is capable of making a mothers contractions more strong (Mathew, par. 6). The CTG detects whether the baby has a good response to the powerful contractions or whether it does not. In this instance, the doctor keeps the belts strapped on the mother until she reaches the stage of labor. Incase the CTG shows that the heart rate of the baby is declining at a high rate compared to the contractions, the doctor then gives the mother a drug to trim down their vigor.
Neonatal seizures are considerably reduced by the frequent CTG tests carried out on mothers (Nardin, 2007). However, the application of constant CTG in lots of health centers in the majority of developing nations is not considered a standard process and at times is by no means carried out. In its place, a permutation of intermittent auscultation, with intermittent CTG with the use of devices that are handheld or Pinard stethoscope amidst footage phases is in numerous instances observed and acknowledged as average performance (Nardin, 2007). These arrangements permit maximization in the utilization of the frequently inadequate amount of consumables and cardiotocographs.
Cardiotocography (CTG) Tracing Requirement (Parameter Description)
Evidently, cardiotocogram comprises of two different signals, which include the uterine activity (UC) and the instantaneous fetal heart rate (FHR). The instantaneous fetal heart rate denotes the interactions between the sympathetic and parasympathetic system nervous of the fetus. Motivation of the parasympathetic nervous system leads to reduced heart rate of the fetus, while the motivation of the sympathetic nervous system leads to heightened heart rate. When the fetus is experiencing a stressful situation, for instance, during the uterine contractions at delivery, the sympathetic nerves aid the fetal heart, pumping activity and it is presented in the fetal heart rate signal variations. In the interpretation of cardiotocogram, four parameters are taken into consideration. The parameters relate to fetal heart rate, baseline heart rate, uterine contractions, accelerations as well as decelerations and baseline variability (Macones et al., 2008, pp. 661-666).
Baseline fetal heart rate (FHR) is defined by NICHD nomenclature as being approximated by the average FHR that is rounded into augmentations of five beats for every minute in a ten minute window, but not including decelerations, accelerations and phases of noticeable FHR variability (exceeding 25 bpm) (Macones et al., 2008, pp. 661-666). It's a mandate to have a minimum of two minutes of a particular baseline sections in every ten minute window. In this instance, it might be significant to turn to the preceding ten-minute window for the baseline determination. When FHR is below 110 bpm, it is an abnormal baseline and it is referred to as bradycardia, whilst when the FHR is beyond 160 bpm, it is a normal baseline and it is referred to as tachycardia.
Acceleration is defined as a visually clear sudden amplification in FHR (Macones et al., 2008, pp. 661-666). A sudden boost is delineated as amplification from the start of acceleration to the crest in thirty seconds or below. In order to be termed as acceleration, the crest should be beyond or equivalent to 15 bpm, and besides, such acceleration must go beyond or equal to fifteen seconds. An extended acceleration exceeds or equals two minutes, but it is below ten minutes in length. A baseline change is an acceleration that lasts for more than or equal to ten minutes.
In the uterine activity, there are several factors used in assessing it. They are as follows: frequency that is the sum of time between contractions to the next, duration is the sum of time from the commencement of a particular contraction to its end; intensity measures the strength of a contraction, while the resting tone checks how calm the uterus is during contractions. Finally, the interval is the time amidst the stop of a contraction to the start of the subsequent contraction (Macones et al, 2008, pp. 661-666).
The baseline FHR variability is defined by the NICHD nomenclature as being verified in a window that is 10 minute excluding decelerations and accelerations. It is also defined as oscillation in the baseline FHR that are not regular in frequency and amplitude (Macones et al, 2008, pp. 661-666). FHR variability can be put in different categories using the quantified amplitude that is minimal to less than 5bpm or equal to that and is beyond undetectable, a marked that is more than 25bpm, and absent that is undetectable and moderate meaning its between 6bpm to 25bpm.
Periodic decelerations are those that are connected to contractions, while episodic decelerations are those that are not connected to contractions. The four types of decelerations according to the NICHD nomenclature are early deceleration, late deceleration, variable deceleration and prolonged deceleration (Macones et al, 2008, pp. 661-666).
The NICHD job group projected terms for a three-tiered structure to reinstate the previous terms that are not defined as none reassuring and reassuring (Macones et al, 2008, pp. 661-666). In the first category that is normal, tracings everyone results available are robustly analytical of ordinary acid-base in the status of the fetus during the observation and a standard follow-up of the fetus is done. In the second category also known as indeterminate, tracing cannot be predicted on the unusual acid-base status of the fetus, but assessment and constant observation and reassessments are pointed out. In the last category, also known as the abnormal tracing can be predicted by the unusual acid-base status of the fetus during observation. However, this needs timely management and evaluation (Macones et al, 2008, pp. 661-666).
Cardiotocography is the concurrent footage of the fetal heart rate as well as the uterine contractions by the use of two detached transducers at the abdominal wall of the mother. The fetal heart rate is chronicled using the abdominal Doppler ultrasound transducer. On the other hand, the uterine contractions are assessed using the abdominal wall pressure beam. Apparently, this technique is mainly used in the third trimester of the pregnancy, particularly near term, as well as in labor, to screen the fetus and diagnose in time any adjustment of its state, as a result of the decline of the oxygen status. In the past, Cardiotocography trace was inferred in a visual method, though by using the high intraas as well as inter-observer capriciousness. The computerized analysis, unlike the visual assessment, has a number of advantages. For instance, it enables a more impartial elucidation, as it's situated on a well standard and it offers more parameters. For instance, the short-term erraticism and estimated entropy, precisely linked to fetal hypoxia, and seems to be associated with less time spent in testing and with a reduction of supplementary numbers of test to be tested for evaluation of fetal (Arduini et al., 1993, pp. 159-163). Additionally, the computerized examination enables the reoccurrence of the results acquired from the distinct centers. Basically, all pregnant women who are susceptible undertake an electronic fetal monitoring during the last trimester of their pregnancy either every day or per every week. Generally, concentrated ante partum fetal observation is entreated in pregnancies, where there is a high risk of ante partum fetal death, as a result of either maternal condition or pregnancy-related conditions (Arduini et al., 1993, pp. 159-163).
In addition to this, a computerized system offers quantified data encompassing analysis of tendencies, reduced medico-legal susceptibility regarding lost CTG dashes, and simple recovery of applicable cardiotographic traces for the purposes of education amongst others (Geijn, 2011, par.24). The presently available integration of various maternal (blood pressure, electrocardiogram, oxygen saturation and heart rate rhythm) and fetal (oxygen saturation, heart rhythm) variables in a single monitor provides additional options for monitoring the fetal in future, specifically research on the impacts of modifications in the parental cardiovascular status on the fetus condition (Geijn, 2011, par.24). Studies have proven that, there are preliminary experiences for managers who support computerized systems wherein biochemical, biophysical and clinical of the fetus and the mother are incorporated. However, the computerized system still requires further study (Geijn, 2011, par.24).
Contemporary Cardiotocography schemes are frequently associated to a central observing station and, consequently, the Cardiotocography can be observed away from the women and chronicled as well as stored in a computer system (Grivell, 2010, p. 5). Nonetheless, there is a probability that this would lead to some women experiencing a feeling of an overly practical atmosphere during labor and generally, this could lead to increased caesarean section rate (Grivell, 2010, p. 5). Subsequently, from the 1990s, computerized fetal heart rate examination systems were introduced to give room for the automated assessment of the Cardiotocography. (Grivell, 2010, p. 5). In addition, it is perceived that the computerized Cardiotocography evaluation system that will be able to get some extra diagnostic data from the fetal heart rate signal as compared to the visual evaluation alone (Grivell, 2010, p. 5). The computerized Cardiotocography has been reconnoitered in a number of clinical circumstances, which includes fetal growth limitation, preterm rupture of the membranes, post- term pregnancy and in pregnancies without increased risk factors (Grivell, 2010, p. 5).
Objectives of Cardiotocography
As defined above, Cardiotocography is a method of screening that is employed in pregnancy with the intention of identifying fetus at a danger of getting hypoxia (Okusanya, 2010, par.1). Data obtained from observational researches offered the perception that Cardiotocography might be an asset in checking initial poor fetus results and this point toward the requirement for interventions to assist in improving the opportunities of the survival of babies who are newly born (Okusanya, 2010, par.1). The main objective of CTG is to check if the heartbeats of your baby are at a regular rate and changeability. The Cardiotocography test is carried out during the third trimester in various circumstances including: when the mother feels that the baby has slowed down the movements or when such movements have turned out to be irregular, if there are suspicions in regards to the predicaments linked with the placenta that may limit blood circulation to the fetus, in case the mother may be expecting twins, low levels of amniotic fluids or if there is a case of hypertension or diabetes in the mother. Nevertheless, research has pointed out that the use of CTG test by may result clinicians to make use of inappropriate or unnecessary interventions due to interobserver errors linked with its visual analysis. According to Okusanya (2010, par.1), non-reactive Cardiotocography might be linked with the amplified mortality and fetal morbidity. Computerized system of study has been formed so as to give a more reliable and objective interpretation due to the errors linked with visual interpretation of Cardiotocography results.