One rationale for IV's in labor is to supply fluids when women are not
allowed to take fluids by mouth.  Of course, if you let women drink to
thirst, and encourage them to do so, they generally get along fine without
IV's.  There are some serious potential problems with the use of IV's: they
can cause fluid and electrolyte imbalances in both laboring moms and in the
new baby; IV D5W as someone else pointed out, I think, may create
hypoglycemia in the newborn in the early hours post-birth, and may also
contribute to causing neonatal jaundice.  In addition, IV's give women the
impression they are "sick" rather than experiencing a normal physiologic
process,  decrease mobility which may inadvertently increase both pain and
anxiety and lead, perhaps, to further interventions.  If a woman is vomiting
and can't keep anything down, an IV is a reasonable intervention.  IV's are
also needed when certain medications are administered or if labor is being
induced.  It may be reasonable to establish some IV access in a woman with a
history of postpartum hemorrhage, especially if she had a previous severe
bleed, but this can be done by way of a saline lock.  I have been at
hundreds of births and seen my share of bleeds.  Every medication available
to stop hemorrhaging post-partum can be given IM so that an IV or saline
lock is not necessary for every woman in labor,  and there has been plenty
of time in every bleed I have ever personally dealt with to establish an IV
if needed.

I would like to see some further dialog about pain medications in labor.   I
have read that demerol, a commonly given pain medication,  breaks down to a
substance called normeperidene (sp?) which has a very long half-life and can
stay in a newborn's body for up to a week or so.  Side effects of this
metabolite include fussiness and poor sucking.  Also, obviously, if given at
the wrong time, demoral can cause respiratory depression, and sleepiness.
Does anyone have info about some of the other drugs like Stadol or Nubain
and their potential effects on the baby, other than respiratory depression?
One of my texts mentions that the advantage of these medications are that
they have a ceiling for respiratory depression with repeated doses.   I saw
a study in the "Journal of Nurse-Midwifery" in the past year that indicated
that the time to first effective nursing was longer if the mother received
medication earlier in labor (4 to 6 hours rather than in the last 1 to 2
hours, I believe).  The medication in use was Stadol.  Does anyone have any
comments about this?  As a birth practitioner,  there are times when I will
want to be able to offer medication in labor.  Epidurals and intrathecals
(the type of epidural where a mom receives spinal narcotics but no
anesthetic -- also known as a `walking epidural') are not always practical
or what is needed......  TIA for any input you have about this.  :-)