Computerised analysis of unstimulated and stimulated behaviour in fetuses with intrauterine growth restriction

Unstimulated (passive) and stimulated behaviour, in the form of fetal heart rate (FHR) and activity (FA)) was studied in 32 normal fetuses and 14 fetu ses with intrauterine growth restriction (IUGR). FHR and FA were recorded u sing a single 1.5 MHz ultrasound transducer and analysed by computer. A 5 s vibroacoustic stimulus (VAS) (electronic artificial larynx) was used for t he stimulation studies. The IUGR fetuses had significantly different patter ns of both unstimulated and stimulated behaviour compared to normally grown fetuses. When unstimulated they had lower FA rates than the normally grown fetuses but this was only statistically significant at: 28-31 weeks. They also spent a significantly lower proportion of time exhibiting high FHR var iation at 28-31 weeks. Following VAS the IUGR fetuses had tower FA response s at all gestations and lower FHR responses from 32 weeks, though only the differences in FA response at 28-31 weeks were statistically significant. O f the 14 fetuses with IUGR, all but one exhibited passive behaviour (ERR an d/or FA) that was outside the 10-90th range, for normally grown fetuses, wh ilst 6 of the 14 had responses to VAS that were within the normal range. We do not feel that computerised assessment of stimulated behaviour in preter m IUGR fetuses confers any advantage over passive observations. (C) 1999 El sevier Science Ireland Ltd. All rights reserved.