I have just read this article by Buhimschi (2004) and would like to comment
upon it and encourage critical reading skills for anyone else who reads it.
 
OF INTEREST:
*Discussion noting progression of mammogenesis during pregnancy: Gland
cellular hyperplasia (proliferation of cells) dominates during first half of
pregnancy then largely ceases; cellular hypertrophy, increase in size of
cells and gland, then takes over. It is in the latter half of pregnancy that
alveolar tissue differentiates into secretory epithelium. This discussion
suggests that the belief that women are ready to lactate after the first
20-24 wks of pregnancy is not solid; legitimate changes are still taking
place and may not be far enough along in some women who deliver early to
produce a good milk supply from the outset.
 
*Cited Yin and Arita as demonstrating "maximal proliferative capacity" of
lactotrophs (pituitary cells that make prolactin) between the day of
parturition and and day 2 of lactation. Might this play into the possible
importance/value of early and frequent stimulation to get milk supply off to
good start?
 
*Statement that prolactin increases during pregnancy *in primates* with
increasing levels of placental progesterone. If this statement is indeed
correct, this might give credence to the theory put forth by people like
Katarina Dalton who believe that progesterone supplementation during
pregnancy increases milk production after birth.  It also might help to
explain the findings of Bodley and Powers (luteal phase insufficiency case)
that progesterone supplementation during second successful pregnancy may
have been responsible for successful lactation after primary failure with
first baby.  Question: if the relationship exists, does it work both ways?
Would lower progesterone lead to lower prolactin?
 
*Discussion of prolactin's ability to upregulate its own receptors.
 
*Failure of early removal of colostrum from the breast is associated with
high milk sodium and poor prognosis for successful lactation in many women."
(cited Neville and Morton 2001)
 
*Serum prolactin levels return to "normal ranges" within 6 mos among women
who breastfeed 1-3x/day. "Elevated prolactin levels could be maintained only
if the baby is nursed at least six times a day."  May explain why so many
women "run out of milk" and "have to give a bottle" after 6 mos.........
;-)
 
*Galactokinetic refers to ability to induce milk ejection
 
 
OF QUESTION:
*In anatomy discussion they refer to lactiferous sinuses, which Hartmann's
group has now largely discounted
 
*Apparent error in statement that "L-Dopa (a dopamine antagonist) is
followed rapidly by a decrease in prolactin levels."  L-Dopa is more of an
agonist; it is a precursor of dopamine that is converted into dopamine, and
*dopamine* is indeed inhibitory. "Antagonist" was incorrect. 
 
*Same paragraph also says that dopamine inhibits prolactin release but not
"does not alter prolactin synthesis," but in the next sentence discusses an
indirect pathway for dopamine to aid in suppression of prolactin gene
expression and lactotroph proliferation. The bottom line is that this effect
alters synthesis. 
 
*cited '86 and '77 articles saying that prolactin takes a dip (nadir) about
9 hrs postpartum-- is this a physiologic phenomenon or perhaps due to
mother-infant separation after birth, especially during the 70's and 80's?
 
*Information on oxytocin interfering with prolactin release does not reflect
some new knowledge.  
 
*Section on galactopoiesis, the maintenance of milk production, did not name
or discuss autocrine theory.
 
*Cited old studies saying that prolactin levels decrease by 2-3 wks
postpartum to levels in "the upper level of normal for nonpregnant women."
This disagrees with Lawrence and Hartmann. I suspect they were studying
women with low frequency of breastfeeding, but this was presented as normal.
They do later discuss frequency issues (above)
 
*comment that "powerful evidence suggests that suckling and increased levels
of *estrogens* are the most important physiologic stimuli for prolactin
release." Huh?  We know that estrogen postpartum inhibits lactation, and
they even go on to mention that estrogen levels decline after delivery!  And
then they say that elevated prolactin levels are critical for adequate
galactopoiesis. 
 
SUMMARY: This article did not cite any of Hartmann's or Woolridge's work. It
seemed to ignore the work within our profession and a large majority of the
citations were 10-20 years old or older. I have not read all of their cited
references, but it is hard to trust that this article reflected the most
current knowledge in light of all the work that was also neglected.  I
suggest that readers be cautious and compare this info to others before
citing it authoritatively. 
 
~Lisa Marasco MA IBCLC

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