This has never been studied as far as I know. However, I don't believe
that women over 40 produce milk in inadequate amounts. They produce
less than teenagers, (everything slows a bit when you get older) but
teenagers often have problems with overabundance.
I have seen one woman who was *post*menopausal at 48, got pregnant with
a donated ovum, had plenty of milk and breastfed exclusively for 6
months.
Jack Newman, MD, FRCPC