The annual National Neonatal Audit Programme (NNAP) measured mortality in very premature babies, those born at 24 to 31 weeks, at neonatal networks between 2015 and 2018.
Among them was the Staffordshire, Shropshire and Black Country Neonatal Operational Delivery Network (ODN). This includes hospitals in Wolverhampton, Dudley and Walsall. The network merged with another earlier this year.
The region had the highest mortality rate for very premature babies in England and Wales, at 9.8 per cent. That is twice the lowest rate in England and Wales, 4.9 per cent at North Central & North East London.
The average across England and Wales is 6.8 per cent.
The NNAP's report included data for the 1,082 babies born in the Staffordshire, Shropshire and Black Country ODN at 24 to 31 weeks between July 2015 and June 2018.
It found that 107 of them died before being discharged home or 44 weeks after birth, whichever occurred sooner. After adjustment, the mortality rate was found to be 9.8 per cent.
The Staffordshire, Shropshire and Black Country ODN included Wolverhampton's New Cross Hospital, Russells Hall in Dudley, Walsall Manor Hospital, Birmingham City Hospital and Princess Royal Hospital in Telford.
A cap on births at Walsall Manor Hospital, put in place following an "inadequate" rating by the Care Quality Commission in 2016, was eased earlier this year, while more women are being encouraged to give birth at Stafford's County Hospital amid low usage.
Earlier this year it merged with the Southern West Midlands network to form the West Midlands Neonatal ODN.
A charity has called for neonatal networks to improve "without delay" but also urged the Government to act quickly in making sure care is sufficiently resourced.
The report contained recommendations for reducing mortality in very premature babies. They include to consider a review of network structure and practices, as well as "evidence-based strategies".
The report also found that less than half of the neonatal unit shifts in Staffordshire, Shropshire and the Black Country are staffed with the nationally recommended number of nurses.
Just 42.8 of neonatal shifts are numerically staffed according to national guidelines while 32.3 per cent of neonatal shifts have the recommended number of nurses ‘qualified in speciality’ to care for the babies on the unit.
The figures across Britain are 64 per cent and 44 per cent respectively.
Justin Irwin, chief executive of the premature and sick baby charity Bliss, said: “It’s deeply concerning to see unwarranted variation in neonatal mortality between different neonatal networks.
“The death of a baby has a devastating impact on the families behind these statistics and we encourage networks to implement the recommendations in the NNAP report without delay.
“However, this must be underpinned by swift action from the Government to ensure neonatal care is sufficiently resourced so that all pre-term or sick babies receive the expert care they need. This is vital for every baby to have the best chance of survival and quality of life.”