Paula Ray wrote:
<<<In our hospital I have also seen a delay in milk production, (sometime not
until day 4 - 5 ) with pitocin inductions, and with moms who were on Mag
sulfate.  This is purely anecdotal, but I do often reassure these moms that I
have seen delays in cases like theirs, and the milk will come....meanwhile, I
watch these babies close for wt. and dehydration.....
Paula J. Ray  RNC , IBCLC
Longview, Texas>>>>
---
This observation would make a great research topic. It is important to
remember that it may not be the medication that is causing the delayed
lactation, but the underlying condition for which the medication was used.
 The fluid shifts in hypertension may be more of a cause than the pitocin or
magnesium sulfate.
Pitocins antidiuretic effect may be responsible for some of the observed
delay as it is noted that the milk "comes in" when diuresis begins.  I have
noticed this effect with preterm delivery moms who had pre-eclampsia.