Alicia:  Here's one reference:  Oyer D, Stone NJ.  Cholesterol levels and
the breast-feeding mom.  JAMA Feb. 17, 1989;261(7):1064.  It shows that
although the total level is high, the HDL (good, heart-protective)
cholesterol is high.  Weaning may even lead to a less favorable
cholesterol profile. So this high cholesterol is probably of no concern,
and even if her HDL were not high and her
cholesterol profile looked lik a high risk one, let's put the whole thing
in perspective.  High cholesterol increases risk of heart disease over a
matter of years and decades, not months.  If this mother is relatively
young and has no other significant risks for heart attacks (e.g. high
blood pressure, smoking, diabetes, family history of heart attacks before
age 50), then what harm can come from putting off lipid-lowering treatment
for the duration of her breastfeeding, be it 6 months or 36 or even more?
Of course, low-fat, high fiber diet and moderate weight loss (if needed),
can't hurt in the meantime.  Hope this helps, Alicia Dermer, MD, IBCLC.