A strapping newborn baby boy is understood to have set a New Zealand record, weighing in at a whopping 6.85kg (15lb 1oz).
A full-term Kiwi baby usually weighs between 3.2kg and 3.5kg, putting this Hamilton infant at double the size of the average newborn, and weighing almost the same as an average 4-month-old.
The baby was born last Monday night at Waikato Hospital, understood to be by Caesarean section, and is now at home with his family.
The child's parents did not want to comment, but the Herald understands the baby is the mother's third child. The mother's Hamilton midwife did not return messages, but welcomed the baby boy on her Facebook page last week, saying it "has to be a New Zealand record".
Waikato District Health Board communications director Mary Anne Gill said the hospital did not have consent to comment about a baby of that weight.
The baby holding the record for the biggest infant born in New Zealand was previously believed to be a 6.63kg girl named Angelani, with Tongan parents, in 2005.
Auckland-based GP and obstetrician Dr Jon Wilcox, who has 30 years' experience delivering babies, said 6.84kg was "massive" for an infant and quite likely New Zealand's biggest baby. The heaviest he had delivered in his career weighed 5kg. Anything over 4kg was considered big.
In New Zealand 78.9 per cent of babies fell between what was deemed as being an appropriate birth weight of between 2.5kg and 4kg, according to the long-term Growing Up in New Zealand study following 7000 babies born in 2009 and 2010 into adulthood.
In total 16.2 per cent had high birth weights over 4kg and 4.9 per cent had low birth weights under 2.5kg. On average boys were just over 100g heavier than girls. The babies in the study were also on average 100g heavier than babies born in 2004.
Dr Wilcox said gestational diabetes was a common reason for having a bigger baby as the infant consumed too much glucose which turned to fat, but this was often picked up during the pregnancy and the baby was often induced at term.
Bigger babies were treated with as much care as premature babies because of potential health risks, he said.
"If you look at the average birth weight they tend to go up quite steadily with each baby."
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