[Determination of diazepam concentration in maternal and fetal serum after intravenous administration during active phase of labor and its effects on neonates].

OBJECTIVE

To investigate the effects of diazepam on the neonates administered intravenously during the active phase in labour.

METHODS

Sixty normal term parturients during the active phase of labour with the cervical dilatation to 3-5 cm were randomly divided into two groups, study group (n = 30) and control group (n = 30). In study group 10mg diazepam was administered intravenously. The concentrations of diazepam and demethyldiazepam in maternal and cord serum were measured by high performance liquid chromatography and neonatal arterial blood gas and Apgar scoring were determined immediately after birth.

RESULTS

At delivery, the mean level of diazepam in umbilical cord serum was 947 +/- 314 micrograms/L, markedly higher than that of maternal serum which was 488 +/- 300 micrograms/L, while the mean levels of demethyldiazepam were not significantly different in maternal and fetal serum. There was no marked difference between the two groups in fetal arterial blood gas and acidbase status. However, the rates of respiratory depression and muscle tone inhibition in the neonates of study groups (63.3% and 26.7% respectively) were significantly higher than those in the control group (30% and 3.3% respectively) (P < 0.05, P < 0.01).

CONCLUSIONS

Use of diazepam in pregnant women during active phase of labour may cause depression of neonatal respiration.