[Evaluation of a non-stress test by automated FHR (fetal heart rate) analysis].

The changes in 5 parameters in 1080 5 minute periods obtained by automated FHR analysis were evaluated in 140 normal and premature labor patients at 26 to 41 weeks of gestation. The FHR-baseline level was between 140.29 +/- 5.04 and 146.90 +/- 6.94 bpm and showed no significant change between 29 and 31 weeks, but then gradually declined to 134.55 +/- 15.74 bpm by the 41st week. FHR-baseline variability (LTV) showed no significant change in the period between 26 and 32 weeks, and increased to 12.82 +/- 3.16 bpm by the 41st week from 9.96 +/- 3.78 bpm in the 33rd week. Variability in a minute was 4.09 +/- 1.03 at 28 weeks, then increased to 5.63 +/- 0.81 by the 41st week. Variability of which the amplitude was 5 bpm or more in 5 minutes showed no change from the 26th to the 41st week. FHR acceleration in 20 minutes was 1.714 +/- 1.204 at 26 weeks, then increased to 4.357 +/- 2.805 by the 40th week, and the mean values were always more than 2 after 30 weeks.