Families are being asked to bring their own ready-mixed formula if they are expecting to bottle feed by the Hull University Teaching Hospitals NHS Trust.
This will provide greater protection for infants, the trust says, and will help new families by protecting the "privacy and dignity" of those on the ward.
“If parents opt to bottle feed their babies, we’re asking them to bring in small, prepared single-use feeds as we will no longer hold a stock of bottles, teats or formula milk in the hospital," said Janet Cairns, head of midwifery.
“Previously, we allowed families to decant milk into bottles but spilt milk was not being cleared up.
"This was causing contamination of the cupboards below and introducing the risk of potential infection issues.”
The change is being introduced to follow infection control guidance, the trust says. As well as ending contamination of ward cupboards, the new rules will help families, it adds.
“Having their own bottles of formula milk will stop mums and their birth partners having to move away from their babies to make up feeds, especially at night," Ms Cairns added.
“It also means other families won’t be disturbed, improving the privacy and dignity for everyone on our wards.”
The move follows similar policies at some other hospitals in the region, with Leeds Teaching Hospitals NHS Trust bringing in measures in 2017.
The trust did not have facilities for the safe preparation of powdered formula on maternity wards, it said, informing parents they would need to bring their own.