URINE PRODUCTION-RATE IS RELATED TO BEHAVIORAL STATES IN THE NEAR-TERM HUMAN FETUS

Objective To investigate the relation between hourly fetal urine produ ction rate (HFUPR) and behavioural states 1F and 2F (corresponding to quiet and active sleep, respectively) in normal near term fetuses. Des ign An observational study. Setting A clinic for antenatal care at a u niversity hospital. Subjects Nineteen healthy pregnant women examined at 37 to 40 weeks of gestation. Main outcome measures Fetal behavioura l states (1F and 2F) were assessed by means of fetal heart rate patter ns (FHR A and FHR B). Using real time ultrasonography, HFUPR (ml/h) wa s estimated during behavioural states 1F and 2F. Results During behavi oural state IF, HFUPR was significantly higher than during state 2F (P <0.01). HFUPR falls by 47% from 50.8 +/- 24.4 ml/h in state IF to 25.7 +/- 15.0 ml/h in state 2F. Conclusions During active sleep (state 2F) hourly fetal urine production rate is considerably reduced as compare d to quiet sleep (state 1F).