I don’t think you are supposed to use the Libre on children under 4.
Yes, Abbott don’t recommend it. But our family decided to just take the risk since it’s really tough to prick a toddler’s fingers 7-8 times a day. And I’d like to think that it’s not really about some harmful effect, but just that they don’t have enough research evidence or government approval to recommend it to younger children. Kind of like the way that Lantus is approved only for children who are at least 6yo, but some doctors are prescribing it for younger children anyway. (Lantus works better than Levemir for my son, by the way). After there are enough data gathered to support it, Libre or Lantus might lower the age limit. That’s just how research and approval goes. Limits are not written in stone, but reevaluated time after time. It’s just up to us whether the potential benefit is worth the risk, and in case of libre, I think it is.