Two small children were treated in a Tennessee hospital this month after getting sick from a new baby formula that they were put on due to the nationwide shortage, The Hill.

The children, who were hospitalized at Le Bonheur Children’s Hospital, both had “special medical needs that have specific dietary requirements,” said Mark Corkins, division chief of pediatric gastroenterology at Le Bonheur and the University of Tennessee Health Science Center.

The children’s bodies “did not adapt well” to a new type of formula that was used amid shortages, causing them to need treatment through IV fluids.

Corkins said that parents should contact their pediatrician if they notice their child isn’t adapting well to a formula or they simply have questions, adding that, “[t]his can be a complicated and cumbersome process and is extremely difficult for parents to navigate on their own.”

The nationwide formula shortage got much worse after a recall from one of the largest formula manufacturers, Abbott Nutrition. President Biden says officials are working to increase the supply of overseas shipments to stock shelves in the short term.