[Pattern of normal fetal heart rate in the third trimester of pregnancy]. / Il profilo della frequenza cardiaca fetale media nel corso del terzo trimestre di gravidanza.

BACKGROUND: It has been shown by previous studies that the mean fetal heart rate (FHR) decreases from the 11th to the 30th week, afterwards the values remain more stable. In the present study we evaluated the FHR pattern throughout the last stages of pregnancy and particularly we estimated the interindividual variability to achieve the maturation of the parasympathetic nervous system in the control of the FHR rythm. METHODS: Serial FHR determinations were made from the 28th week until term in 126 physiological pregnancies, submitted to umbilical Doppler velocimetry. The mean FHR was measured on the length of 6 cardiac beats. The FHR patterns of 48 healthy pregnancies, were also analyzed longitudinally. RESULTS: The transversal data, related to the 126 physiological pregnancies, show a further decrease of the FHR during the last stages of pregnancy: from the 28th to 40th week it drops from the average value of 141 bpm to 133 bpm (r = -0.1469). The longitudinal data show that this decrease occurs in 27% of patients between the 30th and the 33rd week and in 73% of patients between the 34th and the 40th week. CONCLUSIONS: The conclusion is drawn that the physiological decrease of the mean FHR value occurs for each fetus at different gestational ages due to a different balance between the sympathetic and parasympathetic tone; moreover, we find that the interindividual variability in achieving the full maturation of the parasympathetic nervous system is quite wide.

[Cardiotocographic monitoring of fetal health. Comparative evaluation of traditional and computerized methods]. / Monitoraggio cardiotocografico del benessere fetale. Valutazione comparativa fra la metodica tradizionale e quella computerizzata.

One hundred physiological pregnant women and 76 pathological pregnant women suffering from gestational diabetes and pregnancy-induced hypertension underwent a cardiotocographic examination during the course of routine diagnostic tests. The interpretation of cardiotocographic printouts was carried out using traditional as well as computerised methods. The outcome of these tests was then related to neonatal outcome and other parameters which contributed to defining the prognosis of pregnancy. Computerised analysis was found to provide a more reliable diagnosis in comparison to traditional methods in identifying those pregnancies with a pathological neonatal outcome. In particular, in the group of physiological pregnancies, computerised interpretation proved more reliable in 87.5% of cases in which neonatal outcome was pathological; on the contrary, traditional interpretations only revealed 37.5% of the same cases. In pathological pregnancies, automatic interpretation was also found to be more reliable in predicting the non-pathological outcomes, whereas traditional methods provided a high incidence of uncertain answers.