Placental transfer and neonatal effects of propofol in caesarean section

To assess transplacental passage of propofol by measuring the levels in maternal and foetal plasma, and the possible relationship between the latter and the neonatal effects when propofol is used as an induction agent in obstetric anaesthesia for performing a caesarean section to terminate pregnancy.

Intravenous propofol was administered as an anaesthesia-inducing agent at doses of 2 mg/kg in 10 healthy women (ASA I-II). The propofol concentrations were measured by high-performance liquid chromatography (HPLC).

After induction, hypnosis was achieved in all patients within 75 s, and it took 4-10 min to deliver the foetus. Apgar test scores were high in seven of the 10 neonates, in three cases the score was 5 or less. The mean values in venous maternal blood were 5.01+/-1.06 microg/ml 1 min after propofol administration and 1.47+/-0.35 microg/ml at the time of delivery. Propofol crossed the placental barrier with levels in the umbilical cord of 0.32+/-0.10 microg/ml in the vein and 0.22+/-0.08 microg/ml in the artery.

Propofol plasma levels in the newborn at the time of delivery depend on the level in maternal plasma, and therefore on the dose used for induction and the time lapsed between the administration of the drug and the delivery of the foetus.