Dear Sarah,
  I had a child (my second) who did not gain between 12 and 15 months,
according to the doctor's scale.  He had had a stomach ailment of some kind at
14 months which really took a lot out of him.  He had only breastmilk for the
better part of one week whereas before he had nursed quite a bit but also
eaten several small solid meals per day.  I can't be certain, but I believe
that he lost close to one pound during his illness.  That weight loss made his
15 month check up look pretty bad, but *I* knew what the reason was!
  The other thing that occurred was that at a doctor visit 6 weeks after 15
month check, his weight was *two full pounds* above the 15 month check.  I
really doubt that he had gained two pounds in 6wks!  I hadn't paid close
attention to the scale when he was put on, but it's always possible that a
mistake had been made in the prior reading.
  The long and short- has baby had an illness that could have had a negative
effect on weight gain during 12-15 months?  Did mom ask for a re-check?

BTW, my son is 36" tall and about 30 lbs at 26 months.  He also *never* even
looked thru (never mind opened!) the so-called window of opportunity to wean
at one year!  His window is nailed shut for now...

Lisa Jones in Wellington FL