The region has the second worst figures for deaths in England and Wales.
New data from the Office for National Statistics has shown only the West Midlands has a higher rate.
Across the area nearly five deaths occur per one-thousand within the first 12 months of being born.
That compares with six deaths per one-thousand in the worst region, and just over three per one-thousand in the best (East England). The infant mortality rate for Wales was three deaths per one-thousand.
The figures released were based on those to year-end 2016, when 2,651 infant (those under 1 years-old) deaths were recorded, slightly up on the 2015 figures of 2,578. The mortality rate has generally been following a downward trend since the 1990s.
For England and Wales, rates are significantly better than those from the mid-1980s - in 1986 the rate was 6,313, nearly two-and-a-half times the latest rates published.
For the whole of England infant mortality rates are still higher in socially and economically deprived areas, compared with the least deprived areas, with the rate being more than half that of more affluent regions.
Ethnic minorities are still suffering with the worst mortality rates nationally, although figures are improving.
The report went on to name cancer as still the most common killer of children aged between 1 to 15 years.