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 with unexposed controls.

Design An observational study.

Setting Pregnancy Assessment Centre, University Hospital, Nottingham, UK.

Sample Seventeen fetuses whose mothers were taking anticonvulsants and 94 fetuses 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 in all but four recordings (minimum 49 minutes).

Main outcome measures Behavioural criteria studied were: 1. the relative percentage time spent in low and high variation fetal heart rate patterns; 2. the duration and recurrence of fetal activity; 3. the number of accelerations in low and high fetal heart rate variation; and 4. the number of fetal behavioural state transitions.

Results The two groups were comparable in terms of maternal age, parity, birthweight, Apgar scores and absence of neonatal problems. There was less fetal activity in the anticonvulsant group, but this was only statistically significant at 33–36 weeks in fetal heart rate pattern B (equivalent to state 2F).

Conclusions This study showed that fetuses exposed to anticonvulsant medication exhibited a trend of being less active. There were no other significant differences in behaviour. The data do not support the hypothesis of substantial differences in behaviour in fetuses exposed to anticonvulsants.