YES , hypothyroidism
does cause macrocytosis
, with increase in cell size so increase in MCH and MCV , usually MCV is greater than 100 , there are other causes of macrocytosis as well , but with strong family history , swelling through out the body usually causing increase in weight due to water retention due to Hypothyroidism
Get a recheck of Tsh level
as you have strong history , other cause can be cushing so get cortisol
and acth level done as well , as macrocytosis do occur in this too.
hope this helps.