How should parents who can't find formula feed their babies?

Parents across the U.S. are struggling to find baby formula, spending hours driving to local stores and scouring shelves in search of nutrition for their children.

Millions of babies rely on formula, and more than 40% of the most popular brands are sold out at stores across the nation, according to an analysis of grocery stock from Datasembly. 

For parents who can't get their hands on their babies' usual formula products, pediatricians and maternal health experts have some advice on do's and don'ts amid the shortage.