Maternal Epidural Fentanyl Administered
for Labor Analgesia Is Found
in Neonatal Urine 24 Hours After Birth
Albert Moore, Aly el-Bahrawy, Roupen Hatzakorzian, and William Li-Pi-Shan
Fentanyl is an opioid medication that is given epidu-
rally for labor analgesia. Although fentanyl is commonly
used, there are reports of it interfering with breastfeeding
We could ﬁnd no information on whether fentanyl
would be found in a neonate more than 24 hours after delivery
and so decided to present this case.
The patient gave consent, and the research ethics board gave
approval for this study. A 34-year-old, 39-week gravida 1 para
0 woman presented in spontaneous labor. She was 162 cm tall,
weighed 75 kg, was healthy, took no medication other than
prenatal vitamins, and had enjoyed an uneventful pregnancy.
She requested and received an epidural at 4:45 h the day of her
admission. The epidural catheter placement was uncompli-
cated, and adequate analgesia was provided using a pump that
infused 0.06% bupivacaine with 2 lg/mL fentanyl at 10 mL/
hour with a patient-controlled 5-mL demand bolus and a
lockout time of 10 minutes. Throughout her labor the patient
received six extra boluses of this solution.
A 3,780-g baby boy was born at 14:08 h, with Apgar scores
of 9 and 9 at 1 and 5 minutes, respectively, and an umbilical
artery pH of 7.19. The epidural pump was stopped soon after
birth, with the patient receiving 140 mL of the epidural so-
lution (280 lg of fentanyl over 11 hours =25 lg/hour). The
patient recovered and was discharged to the postpartum ward
where she was assessed by us the next day. At that time she
had used no medications for pain.
The baby-dependent items on the LATCH score were as-
sessed, and the latching ability and audible swallowing were
rated at 2 (normal). Urine samples were collected from the
mother at 14:00 h. At the same time, a clean sponge was
placed in a new diaper, which provided a neonatal urine
sample that was collected at 17:00 h. The samples were sent
to a toxicology laboratory, where it was determined that the
maternal urinary fentanyl level was 2.0 ng/mL, whereas the
neonatal level was 2.4 ng/mL.
Although it is known that epidurally administered fentanyl
crosses the placenta, it is thought that this leads to clinically
unimportant levels in the neonate.
The measured half-life of
fentanyl administered intravenously to infants 1 day or less of age
is highly variable and ranges from 75 to 441 minutes,
the duration it would remain in the neonate unclear. Our case
demonstrates that fentanyl can persist in the neonate for at least
24 hours after delivery, at amounts that may have clinical effects.
The minimum effective analgesic level of fentanyl in plasma for
adults is 0.63 ng/mL.
Although the corresponding level is un-
known in neonates, a level of 1.1 ng/mL has necessitated pro-
longed intubation in neonates.
The urinary concentration seems
to have some correlation with fentanyl dosage and levels.
Although fentanyl is transferred in breastmilk, it is virtu-
ally undetectable in colostrum 10 hours after it has been given
In addition, fentanyl’s limited oral bioavail-
ability makes us believe the majority of neonatal fentanyl was
from placental transfer and not through breastmilk. Although
our LATCH score was reported as normal, more subtle
markers of breastfeeding difﬁculty may have been found if
we had assessed the Widstrom stages of neonatal breast-
or more severe problems may have occurred if the
patient had required higher fentanyl doses. Adequate initia-
tion is essential for the continued success of breastfeeding,
and it is possible that the presence of neonatal fentanyl could
interfere in the important ﬁrst days of life.
In conclusion, we provide evidence that fentanyl admin-
istered through an epidural for less than 12 hours will remain
in the mother and neonate, even 24 hours after cessation of
the epidural infusion. The clinical implications of this should
be further investigated.
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Volume 11, Number 1, 2016
ªMary Ann Liebert, Inc.
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Address correspondence to:
Albert Moore, MD
Department of Anesthesia
Royal Victoria Hospital
1001 Decaire Boulevard
Montreal, QC, H4A 3J1, Canada