Judy - you asked about a mom wishing to relactate for an l8 month old who
had weaned at 13 months.  I would see no reason why this mom shouldn't make
the attempt, what has she got to lose?  In other words, simply by putting in
the time and effort (manual expression for a few minutes 10 times/day if she
could swing it) she would feel that she was doing something really special
for her baby.  My humble opinion is that even a tiny quantity of breastmilk
every day is better than none.  I have a copy of a research paper written by
Helen Armstrong (and others), "Breastmilk, a Household-level Weaning Food
Resource", which contends that as the quantity of breastmilk decreases
during weaning so the immunological components become more condensed.

The only concern I would have for your client would be that she needs to go
into this with her eyes wide open - if she brings in a small (or large) milk
supply then this will be wonderful;  if she doesn't, then she doesn't, and
she needs to realize that the time that she *did* breastfeed (13 months) has
given her baby the very best start in life.

I am currently working with a mom who weaned a baby at 2 months and decided
to try and relactate at 8 months - a six month gap.  She has not been able
to persuade the baby to take the breast so she started by manually
expressing and has continued with pumping (manual pump, four times each 24
hours now).  Baby is 11 months old now and is receiving nearly 400ml EBM
every day, so she has been "successful" beyond even my wildest hopes.  The
difference in the baby's health (he is IgA deficient) has been nearly
miraculous.

Best wishes to your client, each mom is different but I would certainly
encourage her to give this a whirl!

Pamela Morrison IBCLC, Zimbabwe