Nicolina Newcombe thought her unborn baby was feeling a bit heavy and he definitely knew how to use his legs.
But at the reasonable height of 175cm, the actual size of the Hamilton woman's baby wasn't measuring off scale.
So when he popped out weighing a whopping 5.9kg (131b 7oz) last Wednesday, Newcombe felt a sense of vindication after feeling bad moaning that her boy's kicks were leaving her sore during pregnancy.
The arrival of Tobias shocked not only herself, but also her midwife and other medical staff at Waikato Hospital due to his size.
The average baby would hit the 6kg mark about three months old.
Despite Tobias' size Newcombe was able to deliver him naturally - after being induced at 42 weeks - without the aid of an epidural.
"That was a good thing because if we had have known that he was going to be such a big baby they might not have let me do it naturally."
There were a couple of inklings that Tobias might be oversize because she'd had a few comments about the size of her tummy.
"So many people said to me, 'have you got twins in there?' But I actually did have a baby the size of two babies."
However, her height helped disguise how big Tobias would turn out to be.
It was a bonus for the mum-of-two, who eats and lives organically.
His bulk was such a surprise because his size was measured relative to the size of her tummy and given she was so tall no one picked up that he was extra-big.
""If you look at the chart for birth rate, there's the 99.6 percentile is the highest you can go and he is heaps more off the chart, he's way off the chart.
"The newborn nappy size is 0 to 5kg and he was born 5.9kg, so no newborn clothes fit him."
The initial plan was to have him born at a birthing centre. However, once Newcombe hit 42 weeks she was induced at Waikato Hospital. That turned out to be a stroke of luck because the birth wasn't all plain sailing.
"The service at Waikato Hospital was very, very good. It exceeded our expectations to be in the delivery suite ... but he had shoulder dystocia, which means that his shoulder was stuck in my pelvis.
"He came out head first and once my midwife realised she pressed the emergency button. Heaps of doctors came in and helped pull him out.
"Everybody was like 'wow, what a big baby' and 'how big is he', everyone was really shocked."
The 33-year-old said she was more worried about whether her baby was okay after the additional doctors were called, but he was quickly given the all clear.
"I was more worried if he was okay, and he was fine, so I didn't really care how big he was but I s'pose it's a bit of a thing."
Her son's massive size had also given her a sense of vindication after feeling so tired and sore throughout her pregnancy.
"I had a pretty difficult pregnancy and I was always complaining and I thought 'man, am I soft? Is it really this bad to be pregnant? He's so heavy' ... I felt like my stomach was so heavy and the kicks were really sore and I was really, really tired all the time and I thought to myself that I'm complaining too much.
"When he came out and he was 13 pounds I was like 'see, see, I was allowed to complain, I wasn't making it up'."
She's not sure where Tobias' size comes from. Her husband, Jamie, is shorter than her but she labelled it "a fluke". Her other son weighed in at 3.9kg (8lb 10oz).
"Most babies who are big have gestational diabetes or come from a larger group of people, but I had a negative diabetes screen test."
Midwife Annika Reid said Tobias was definitely a "very, very big baby".
"I myself have had a big baby but mine was a kilogram less than hers and he was large, so for hers to be a whole kilo bigger was like 'wow'," Reid said.
It was the first time the midwife had helped deliver a baby so big and she doubted she would ever again in her career.
"You get a few 10-pounders these days but babies that are 13 pounds, not so much, and I really don't think that I will have a baby that big again during my time as a midwife."
She credited both mum and baby doing so well and remaining healthy due to Newcombe's organic and healthy diet.
"She doesn't eat poorly so we had no reason to think that he was not going to be normal."
She said Newcombe had "many hands on her belly" during her pregnancy from health officials but his large size was simply missed due to her height.
"What an amazing feat. Not many women can say they've given birth to a 13-pound baby."