CHICAGO (CBS) — While hospitals in Illinois are now required to take more steps to encourage mothers to breast-feed their newborns, New York is taking the additional measure of locking up hospitals’ stockpile of infant formula.

Under a new program, reported by the New York Post, new mothers who insist on bottle-feeding will still be able to do so, but nurses would have to sign out the baby formula.

In Illinois, Gov. Pat Quinn signed a law in June that requires Illinois hospitals to develop policies that promote the healthy benefits of breast milk.

The University of Chicago Hospitals does not lock up baby formula, but is developing a policy that would require either a doctor’s order to begin formula feeding or documentation that a nurse counseled the mother on the benefits of breastfeeding over formulas, according to hospital spokeswoman Tiffani Washington.

NorthShore Hospitals keeps formula unlocked but in a location only accessible with help from a nurse. NorthShore also has stopped sending parents home with diaper bags full of formula, according to spokeswoman Colette Urban. They also have consultants on staff to counsel new mothers about breast feeding.

New York Mayor Michael Bloomberg has been criticized over the new policy, which is set to take effect in September.

Critics says the city shouldn’t impose on a mother’s choice to either breast feed or use formula. However, breast-feeding advocates says the policy is a good way to push the benefits of breast milk first.

The New York program is voluntary for hospitals.

The American Academy of Pediatrics recommends that moms exclusively breast-feed for the first six months of a newborn’s life to boost protection against many illnesses and allergies, CBS News reports.