Babies weighing 8lb 13oz (or 4kg) or more are considered unusually large – and their mothers are more likely to need a caesarian section, according to experts.
Women in some parts of the UK are up to five times more likely than others to give birth to super-sized babies, our analysis of birth records reveals.
A range of factors can influence the likelihood of having an unusually large baby, including a mother’s weight and age, genetics, gestational diabetes, and a baby being overdue.
But our analysis of the 2021 figures shows widespread variation in baby weights.
And in South Yorkshire, the heaviest babies are being born in Doncaster – where of the 195 babies born with a known birth weight, a total of 30 were over 4kg, representing just over 15 per cent. That was the 46th highest proportion of all the 324 local authorities in England.
Rotherham is second, with 95 of the births were the 780 babies whose weight was known were over 4kg, just over 12 per cent, ranking it 155 in England.
Sheffield had the second lowest number of ‘big babies' in South Yorkshire, with 485 of the 4,530 babies whose birth weight was known recorded at more than 4kg. That represented 10.7 per cent, and was 202nd nationally. Of these, 15 babies weighed in at over 5kg, or 11 lbs.
Barnsley had the fewest, with 85 of the 810 babies of known birth weight exceeding 4kg, representing 10.5 per cent, and ranked 219th nationally.
However, only eight per cent of birth weights were known in Doncaster, compared to 35 per cent in Rotherham, 86 per cent in Sheffield, and 64 per cent in Barnsley.
Figures for births recording a weight of more than 5kg were not recorded for Barnsley, Rotherham or Doncaster.
Babies are considered unusually large if they weigh at least 8lb 13oz, or 4kg – the equivalent of four bags of sugar. The medical term is foetal macrosomia.
Babies this size can lead to complications during labour, and mothers are more likely to need a caesarian section.
Office for National Statistics (ONS) data shows one in 10 babies in England are unusually large.
Of 569,314 live births with weights recorded in 2020, 57,753 babies (10.1 per cent) tipped the scales at four kilograms or more, with 596 of those weighing in at an incredible five kilograms, or 11lb.
At a local level, it is a midlands council area that claims the crown for England’s biggest babies. In Rugby, 25.6 per cent of babies weighed in at four kilograms, while 2.3 per cent were five kilograms or more.
However, birth weight data was only recorded for one in every five of Rugby’s births, so the data may not show the true picture.
When looking at just areas where weight was recorded for at least half of births, West Devon moves into the top spot, with 21.6 per cent 4kg or heavier.