I am writing in response to two recent questions regarding drugs  used
prior to and during labor.
Prostoglandins , specifically PGE2, sold under the brand names Cervidil and
Prepidil is used for the purpose of cervical ripening in women for whom
induction of labor is deemed necessary but who have an "unripe" cervix.
(Makes it sound like some kind of fruit, huh?)  Anyway, the use of these
agents prior to the administration of oxytocin significantly shortens the
length of labor and reduces the rate of cesarean birth.  These are good
things.  Unfortunately it sounds like the woman who was mentioned had an
unusual reaction to this medication.  The most common side effect is
uterine hypertonus  (which means too many contractions too close together).
 This can result in fetal distress but is fairly easily corrected with the
use of other medications or in the case of the new Cervidil preparation, by
simply removing the tampon-like mesh that holds the drug in the vagina.  It
is administered vaginally and , in my 6 years of experience, is extremely
effective and safe.  As for effect on the baby after birth there should be
none.  These prostoglandins have an extremely short half-life and should be
out of moms system well before delivery.  In addition their action is by
being absorbed locally in the tissues and not systemically.

Now to the subject of Fentanyl.  Fentanyl is a narcotic like substance that
can cause respiratory depression in babies.  It has a short duration of
action and is favored for situations where pain relief needed is immediate
and of short duration.  Narcan is the drug used to reverse respiratory
depression in the neonate and/or mother if needed.  Fentanyl when used in
the epidural space gives the benefit of pain relief without motor block.
In other words the mom can walk in some cases, push more effectively, use
alternative positions for childbirth but still have pain relief.  Another
benefit of administering narcotics into the epidural space is that it
results in less respiratory depression of the neonate as very little gets
into the systemic circulation, unlike when narcotics are given for pain
relief in labor thru IVs.  I believe the possibility of respiratory
depression in the neonate is remote but still possible.  We know the
effects of narcotics in labor on breastfeeding delays are real.  I do feel
that for the mom who needs pain relief in labor these epidurals with
narcotics alone or in combination with local anesthetics are a wonderful
option.  Please know I am an advocate of "natural childbirth"  but also a
realist.