Physiological changes during pregnancy are known to affect the pharmacokinetics of many drugs. Intranasal fentanyl is an interesting option for obstetric analgesia, but its use in pregnant patients has not been established. The investigators studied pharmacokinetics of intranasal fentanyl in labouring women and to subsequently evaluate the maternal and fetal safety after administration.

Inclusion Criteria:

• healthy parturients with uncomplicated, single gestation pregnancies, full term (38-42 weeks of gestation) pregnancy, agreed to participate

Exclusion Criteria:

• a disease that might affect hepatic or renal function, contraindications to opioid analgesics, fetal growth retardation, signs of fetal asphyxia by cardiotocography, meconium stained amniotic fluid or placental insufficiency. The subjects should not have received fentanyl during the previous 14 days.

Not agreed to participate