A comparison of fetal behaviour in term fetuses exposed to anticonvulsant medication with unexposed controls

Objective To compare behaviour in term fetuses exposed to anticonvulsants w ith unexposed controls. Design An observational study. Setting Pregnancy Assessment Centre, University Hospital, Nottingham, UK. Sample Seventeen fetuses whose mothers were taking anticonvulsants and 94 f etuses whose mothers were on no medication between 28 and 41 weeks. Methods Behaviour (fetal heart rate and activity) was recorded with the use of Doppler ultrasound. The duration of recording, was 60 minutes or more i n all but four recordings (minimum 49 minutes). Main outcome measures Behav ioural criteria studied were: 1. the relative percentage time spent in low and high variation fetal heart rate patterns; 2. the duration and recurrenc e of fetal activity; 3. the number of accelerations in low and high fetal h eart rate variation; and 4. the number of fetal behavioural state transitio ns. Results The two groups were comparable in terms of maternal age, parity, bi rthweight, Apgar scores and absence of neonatal problems. There was less fe tal activity in the anticonvulsant group, but this was only statistically s ignificant at 33-36 weeks in fetal heart rate pattern B (equivalent to stat e 2F). Conclusions This study showed that fetuses exposed to anticonvulsant medica tion exhibited a trend of being less active. There were no other significan t differences in behaviour. The data do not support the hypothesis of subst antial differences in behaviour in fetuses exposed to anticonvulsants.