Poorly babies face a postcode lottery on whether they receive important aspects of care, a new report suggests.
Care for babies born prematurely, with health problems or with a low birth weight, is improving overall, but some regions are not delivering gold standard care, according to research comparing neonatal care across England, Scotland and Wales.
It is recommended that magnesium sulphate is given to mothers likely to deliver a pre-term baby to reduce the risk of cerebral palsy in later life.
But the latest National Neonatal Audit Programme report, produced by the Royal College of Paediatrics and Child Health, found that administration rates vary between 26% to 70%.
Meanwhile the authors found no improvement in the rates of breast milk given to pre-term babies.
And they highlighted significant variations around the country.
In some areas only 39% of premature babies are receiving breast milk when they are sent home compared with 78% in other regions.
The authors also found that two in five babies born more than 10 weeks early were not given appropriate follow-up appointments when they were two years old.
But the 2016 report did highlight improvements in some areas compared with previous years, including more parents having consultations with senior medics within a day of their child's admission, more babies receiving eye screening to minimise risk of vision loss, and better monitoring of babies' temperatures.
Around 750,000 babies are born each year across the three nations and nearly one in eight of these will be admitted to a neonatal unit.
Dr Sam Oddie, consultant neonatologist and clinical lead for the report, said: "There is no reason why many of these measures could not be achieved far more successfully - paying attention to the clinical processes and working with the whole involved team to improve them are the keys to improvement.
"For example, we need a health care system where every baby born very early is followed up at two years.
"However, we know that 40% of babies don't have any clinical information at all recorded about their health and development at two years.
"It simply isn't good enough - babies born more than 10 weeks early do sometimes have important problems with their development, and knowing about this at an early stage helps babies, their families and the health service."
But he welcomed improvements in other areas, adding: "The number of units who have made significant improvements to particular aspects of care over a 12-month period is impressive.
"It shows that progress can be made - and the positive impact on the health of these babies can be huge.
"For example, admitting babies with a normal temperature seems to reduce the risks to babies in terms of reducing the severity of illness and is certainly one sign that the initial care of the baby went well."