The predictive value of vibroacoustic stimulation with an acceleration response as a means of ruling out fetal acidosis has been equivocal [32,33]. A number of trials of amnioinfusion, particularly in the presence of oligohy-dramnios, have demonstrated a beneficial effect, reducing variable decelerations and the rate of Caesarean section for fetal distress [34,35].
The assessment of the fetal electrocardiographic (ECG) waveform is an attractive option since the signal can be obtained from the same fetal scalp electrode used for recording the FHR. Laboratory studies have examined the effect of hypoxemia and acidosis on the ST segment. In studies of acute hypoxemia, the ratio of the T-wave height to QRS height increased , although this association has not been a consistent finding . Preliminary clinical observations suggested caution in the interpretation of ST waveforms . The recent development of higher order FHR analysis has provided monitoring systems that can add automated fetal electrocardiographic ST segment analysis to the standard FHR and uterine contraction information which have been applied in a number of clinical trials. Meta-analysis of two randomized clinical trials of FHR assessment with the support of ST waveform analysis has shown that the number of babies born with metabolic acidosis at delivery could be reduced in conjunction with a reduction of operative deliveries for fetal distress . Subsequent reports indicate some limitations of the sensitivity of ST waveform analysis in the identification of fetal asphyxia with a significant metabolic acidosis [40,41].
Fetal pulse oximetry was introduced to provide a non-invasive measure of oxygen saturation to improve intrapartum assessment during labour. However, the randomized clinical trials have not provided convincing evidence that this supplementary test will reduce unnecessary intervention [42,43].
Near-infrared spectroscopy (NIRS) has been developed as a means of continuous, non-invasive real time measurement of change in fetal cerebral oxygenation and hemodynamics during labour. Preliminary reports of the application of this technology for fetal assessment during labour have been published [44,45].
Although these supplementary tests provide additional information, further research remains to be done before the role of these tests in clinical practice can be determined.
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The first trimester is very important for the mother and the baby. For most women it is common to find out about their pregnancy after they have missed their menstrual cycle. Since, not all women note their menstrual cycle and dates of intercourse, it may cause slight confusion about the exact date of conception. That is why most women find out that they are pregnant only after one month of pregnancy.