An independent review has taken place into the deaths of 13 premature babies at the neonatal unit at the Countess of Chester Hospital.
The "unexpected and unexplained" deaths were all between January 2015 and July 2016.
The Royal College of Paediatrics and Child Health made 24 recommendations about standards and staffing at the neonatal unit.
Since July the hospital has stopped treating very premature babies. Mothers expected to give birth more than eight weeks early are transferred to another hospital. This arrangement will continue until the hospital has acted on all the recommendations made in the report.
The report says there is no single cause or factor that explains the increase in deaths of premature babies. It recommends a further review of each neonatal death between January 2015 and July 2016 to see if any factors could have changed the outcomes.