Maternal perception of fetal movements: the optimal duration of a recording period

A regular count of perceived fetal movements by the mother has been proposed as a screening method for the early recognition of fetal distress. Absence or a strongly decreased number of fetal movements during a particular period is considered as a sign of fetal distress. In the study presented, the optimal duration of a recording period for the maternal perception of fetal movements was examined. 186 pregnant patients at gestational ages of 32 and 38 weeks were asked to mark each perceived fetal movement on a time axis for two continuous hours. From these patients an 'optimal' group of 143 pregnancies was selected to constitute the study group. A window technique was applied to the 2 h recordings, searching for periods in which 0, 1 or 2 fetal movements were noted. 23% of the recordings at 32 weeks and 14% at 38 weeks showed absence of fetal movements for at least 30 min. At both 32 weeks and 38 weeks there was absence of fetal movements for more than 1 h in only 1.5% of the recordings. The findings are in agreement with the fetal behavioural state concept. A recording time of 1 h exceeds the normal duration of a fetal quiet-sleep state and minimizes the risk of unjustified suspicion of fetal distress.