Most infant formulas are made from soy products. Use of kitniyot does not apply to infants.
However, you must take care to keep bottles, nipples and formula away from the general kitchen area. Any mixing or washing should be done elsewhere, such as in the bathroom sink.
The following products can be assumed to be free of chometz, although they may contain kitniyot.
Please note that these products are only acceptable when bearing the OU or OU-D symbol.
Berkley & Jensen
Earth’s Best Organic Baby Formula
Gerber Good Start Soy Formula
Home 360 Baby
My Organic Baby
Nestle Good Start
O Organic Baby
Toys ‘R Us
Up & Up
The following three baby formulas are NOT certified kosher by the OU, due to Kashrut concerns. However, if upon consultation a learned Orthodox Rabbi has allowed its usage, they have been found to be free of chometz.
Enfamil Nutramigen Lipil