(LONG)
Joy,
The subject of the effects of the volume of maternal IV fluids has been of
great interest to me too, though my interest is from the aspect of the
differences in timing and degree of edema in the postpartum breast and its
interfererence with comfortable effective latchng and on the timing of the
onset of Lactogenesis II.
I am beginng to be concerned for the sake of the psyche of new mothers whom
I contact through WIC. They are so very vulnerable, and the best educated
ones are even more vulnerable and threatened if a floor nurse or an LC or a
physician (having heard the latest "research buzz"), begins to "throw
around" scientific sounding "per centages of BW lost", and subtly or not
so subtly pressures the mother into supplementation, pumping, etc.
I am particularly curious just how accurately the IV intake is actually
measured. "100 cc. per hour" as I heard quoted by a PhD in a seminar, just
won't hack it. AWHONN protocols for fetal distress suggest that one way to
manage this is to give boluses of IV fluid to mom in labor to boost fetal
BP, and boluses are frequently given as part of anesthetic administration as
well. And then, for purposes of NB weight research, such measurement needs
to be measured separately up TO the tying off and/or birth of the placenta.
How soon was the cord tied?? Was this delayed till placental transfusion was
complete, especially for small babies? I have heard some question as to
whether exogenous pitocin gets to the baby at any time before with its
antidiuretic effects, but our pharmacists need to enlighten us on this as to
half-life in the blood, and length of action on the kidney, fetal and
maternal. How much vasopressor does the baby get when epinephrine is used
during the anesthetic???? How might this effect the newborn kidney, and for
how long?
And then additionally, for purposes of studying breast swelling, following
the birth of the placenta, there would need to be continued separate
measurement of how much further IV fluid the mother gets, and how much total
exgenous pitocin a mother received till IV's were discontinued, sometime
several days later??. This would be necessary in figuring overall total that
would effect the mother's colloid osmotic pressure (COP) and subsequent
fluid dynamics. Anesthesiologists and other physicians are well aware of
potential effects of overhydration on the mothers lungs, but I do not
believe their insight or concern seems to extend to the effect of COP on the
breast in the 10-14 days following their part in the direct care of mothers.
I admire your insights and your determination to formally research this
question about newborn weight loss. Your personal experiences of dialysis
make your awareness doubly insightful. I would like to contribute some of my
own insights.
Although I myself will never be able to contribute directly to formal
research, I have over 60 years total practical experience in observing
newborn infants and more particularly, observing and palpating pregnant and
lactating breasts. This started with being very efficient at applying breast
binders to some very swollen breasts on postpartum night duty when I was a
student nurse in 1948 when students staffed most of the hospital at night.
Twelve months after graduation, I transferred to the OB/GYN/Newborn field
for good, and have worked as a staff nurse on all shifts in all areas of
hospital OB, ending with 7 years as an inservice instructor there, including
being a childbirth educator. I then moved on to 20 years in public health
prenatal and now, since formal retirement, many years on the WIC LC team. My
observations span from the days of general anesthetics with practically no
IV's, in patients who were NPO, (and probably somewhat dehydrated) often
through labors 24-48+ hours long, 3-10 day maternity stays and long feeding
delays and universal supplementation, on through the period of the surge of
interest in natural childbirth and the establishment of family centered
maternity care and more physiologic management of breastfeeding and early
discharge, and then on through the early establishment and later expansion
of modern perinatal care.and the explosion in breast pump technology from
the days of the bicycle horn breast pump. I have been fascinated with the
changes I have seen in postpartum breast swelling during that time, and have
written about some of my insights..
I have not yet had the chance to read beyond the abstract of a
recent article having to do with fetal weight loss. When I do, these are
some of the practical questions I will have in my mind:
We have all heard of meconium stained fluid, an indicator of distress. But
does everyone realize that a baby can void in utero into the amniotic fluid,
without detection, any time on up to the moment of actual birth ?? And other
babies wait to void till after they are weighed!! The second baby has
technically "lost more weight" than the first, even thogh they might have
weighed exactly the same, to the gram, the moment before birth!!
I wonder if babies who are spending immediate lengthy time on the mother's
chest are sometimes voiding on the mother before they are weighed?? I
certainly hope babies are never weighed till they are thoroughly dried,
which may also mean loss of some (weighable) vernix. Better yet, I hope they
are not weighed till after the initial and hopefully long, time period with
mom, which might give them the benefit of having eaten at least a little
something before this almighty important "precise" birthweight statistic is
carved in stone on the chart! Then let the mathematics begin!
These are further questions I will be asking as I read: How is newborn
urinary output measured? The number of diapers, etc. can often depend on how
often the diapers are checked and changed. Or are the diapers weighed?? Are
the standard diapers in use in a particular nursery originally checked on
the electronic scales to see if they are uniform enough to simply collect
the 24 hour diapers each day in a zip-lock bag, also preweighed for
standardization, and then weigh that bag and subtract the dry weight of x
number of diapers plus the original weight of the collection bag before
discarding? Granted, the stool output would get weighed too, but it all
contributes to initial weight loss. It would require a little extra
handwashing for infection control, but it seems more "scientific" than a
"diaper count" if I am interpreting that phrase as simple counting. As you
pointed out, weight "lost" through excreta does not correlate directly with
a lack of caloric intake. It seems self evident that many babies have
more ounces to excrete than the amount they are able to eat from the mother
in the early days!!
You remarked: <I was also aware of fetal physiology and how
the opportunity is there for fetuses to pick up fluid (passive diffusion -
electrolytes [and therefore fluid] move from an area of high concentration
to areas of low concentration). >
Seemingly to the contrary, this is stated in an abstract I found:recently .
. . .<Both umbilical artery colloid osmotic pressure and umbilical vein
colloid osmotic pressure were significantly higher than maternal colloid
osmotic pressure. . . . . .Conclusion: The reduction in the maternal
colloid osmotic pressure during delivery, is, in part related to intravenous
fluid expansion and the amount of vasopressor administered. Despite the
significant fluctuations in maternal colloid osmotic pressure, the placenta
and fetus possess the capability to alter colloid osmotic pressure." (If I
remember correctly, the umbilical VEIN delivers blood from the placenta into
the fetus, while the umbilical ARTERY leads back to the placenta, which is
the opposite way we ordinarily think of the function of veins and arteries.
Therefore I infer from the abstract that it is possible for the baby to
contribute somewhat to the C'OP of the mother, or at least to that of the
cord blood.)
Hauch MA, Gaiser RR, Hartwell BL, Datta S. Maternal and fetal colloid
osmotic pressure following fluid expansion during cesarean section. Crit
Care Med 1995 Mar;23(3):510-4.
I look forward to the results of your research, and especially the
references you find.
K. Jean Cotterman RNC-E, IBCLC
WIC Volunteer LC
Dayton OH
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