there is a great article in eur j obstet repro biol 42: 89-94 1991... it
is included in the 93 neonatal perinatal medicine.....

   bits....

  ... little is known about the transplacental transfer of fentanyl... all of
the infants were in good health and showed normal progress during the first
six days.....fentanyl appeared rapidly in the maternal circulation, with peak
concentrations at 15 or 30 minutes. .. the avr. umbilical concentraion
represented 43% of the maternal concentration at birth..... with the
form...used in this patient group, fentanyl leverls reaching the fetus after
c/s were low and did not affect neonatl condition. NEVERTHELESS, the
likelihood of fentanyl uptake by fetal tissues recommends cation when this
drug is used repradedly during spontaneous or induced labour...

   .. the infants were born at an avr. of 27 minutes after the epidural
injection!

                 Patricia