Seema wrote
<<I am having hard time convincing the pediatrician who I work with about
baby's tummy size. MY coworker Doc doesn't believe the baby's tummy size is
marble size day 1-2. and walnut size at onw week and he doesn;t want to me
to tell my moms this info.>>

Seema, I found a great article on line that has convinced me. Here is the
link.

http://www.pedresearch.org/cgi/content/full/50/5/629

In this study, published in 2001, researchers measured the stomach capacity
of 17 babies in the first 80 hours of life. (I assume they measured each
baby one time.) What happens when an adult or child eats a meal is this: the
stomach wall relaxes to accommodate the increased volume of food. There is
an increase in the capacity of the stomach (because the walls are relaxing)
without an increase in pressure inside the stomach. As more food is taken
in, this relaxation slows and then stops; pressure increases inside the
stomach; the person feels full, and if he or she goes on eating, the person
feels pain. This function of the stomach walls, known as "receptive
relaxation," is a new function in a newborn baby, who until birth has been
swallowing sips of amniotic fluid around the clock but has not been getting
"meals."

Inflating a balloon inside the baby's stomach and measuring the pressure and
volume, the research team observed that there was no period of "receptive
relaxation" in the youngest babies. This was described as having a
"non-compliant stomach." The researchers could observe that relaxation was
beginning to develop and the amount the stomach could hold was increasing,
in even such a short period as the first 80 hours. Two factors statistically
explained about 60% of the increase in stomach capacity: baby's age, and the
number of feedings the baby had had. There were both breastfed and
formula/bottle fed babies in the group tested.

I found the explanation section especially interesting. The authors point
out that newborns are undergoing a lot of physiological changes as they
adapt to extrauterine life, so there could be a great many explanations for
this phenomenon of changes in stomach capacity. Among them:
   1. "the surge and ebb of stress hormones during and after delivery.
Accommodation to luminal distention may be diminished in the first hours of
life because of the dominance of sympathetic tone over parasympathetic
tone." This makes sense to me because I know that stress retards digestion,
so the stress of labor and birth might affect the baby's ability to take in
food at first.
   2. "It is possible that the matrix of connective tissue supporting
gastric smooth muscle requires an initial series of stretches before
becoming relaxed." 
   3. "rapidly changing newborn gut peptide profile" 
   4. "maturation of vagovagal reflexes" This and the previous item make
sense to me also. An obvious change from pre-birth to post-birth existence
is that pre-birth babies don't poop and afterwards they do. Something must
be stirring in the nerves and/or hormones of the gut that provokes this
change. We know that ingesting colostrum helps the process because colostrum
is concentrated and draws water into the lumen of the gut. Also, we know
that sucking and swallowing stimulate gut action all the way down the
line--but they did not do this during gestation, so something about the gut
must change after the birth.
   5. "delayed gastric emptying" because of a hypomotile duodenum. The
author says this has been observed in pre-term babies--so it might be
present in newborn term babies as well.

So this has given me lots to think about, and renewed my respect for Google.
"Seek and ye shall find" should be their motto.

Cheers,
Chris

Chris Mulford, RN, IBCLC
LLL Leader Reserve
working for WIC in South Jersey (Eastern USA)
Co-coordinator, Women & Work Task Force, WABA
 
 

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