Marked fetal acidosis and specific changes in power spectrum analysis of fetal heart rate variability recorded during the last hour of labour.

Autor: Siira SM; Research Centre of Applied and Preventive Cardiovascular Medicine (CAPC), University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland., Ojala TH, Vahlberg TJ, Jalonen JO, Välimäki IA, Rosén KG, Ekholm EM
Jazyk: angličtina
Zdroj: BJOG : an international journal of obstetrics and gynaecology [BJOG] 2005 Apr; Vol. 112 (4), pp. 418-23.
DOI: 10.1111/j.1471-0528.2004.00454.x
Abstrakt: Objective: To assess whether intrapartum acidosis affects specific components of fetal heart rate variability.
Design: Prospective clinical study.
Setting: Twelve Nordic delivery units.
Subjects: Fetal heart rate variability was studied in 334 fetuses divided into two groups according to cord pH value: the acidotic group (cord arterial pH < 7.05 at birth, n= 15) and the control group (cord arterial pH > or =7.05 at birth, n= 319).
Methods: In spectral analysis of fetal heart rate variability, frequencies were integrated over the total frequency band (0.04-1.0 Hz), low-frequency band (0.04-0.15 Hz) and high-frequency band (0.15-1.0 Hz). We also calculated the low-to-high frequency ratio.
Main Outcome Measures: The spectral bands of fetal heart rate variability were compared between the acidotic and control fetuses.
Results: We found that during the last hour of monitoring, baseline fetal heart rate gradually decreased, whereas total, low-frequency and high-frequency fetal heart rate variability initially increased but then, near the delivery, decreased in the acidotic fetuses when compared with the controls. Low-to-high frequency ratio was greater in the acidotic group during the whole study period (P= 0.002). Cord artery pH was inversely associated with total fetal heart rate variability (P < 0.001), low-frequency fetal heart rate variability (P < 0.001) and low-to-high frequency ratio (P= 0.004).
Conclusions: Marked fetal acidosis was associated with frequency-specific changes in fetal heart rate variability as reflecting the compensation ability of autonomic nervous activation during the last hour of labour.
Databáze: MEDLINE
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