Northland mum Kari Muller gives birth to 13lb 6oz son Lewis at Whangārei Hospital

Kari Muller with her 13lb 6oz (6.08kg) son Lewis.

A Northland couple thought their first son’s 11lb 5oz (5.13kg) birth weight was impressive until his younger brother arrived weighing 13lb 6oz (6.08kg).

Kari and William Muller welcomed their second child, Lewis, on January 29 at Whangārei Hospital.

The couple expected a big baby given how their first-born Walter, who turns 2 next month, tipped the scales at birth – but they hadn’t imagined 13lb.

“We were guessing if he was going to be bigger than Walter or not. But we were quite surprised that he was almost a kilo bigger,” Kari said.

Despite Kari being non-diabetic, Lewis tracked about seven weeks ahead in fundal height, the measurement used during pregnancy to gauge a baby’s growth.

“Then we had a scan at 37 weeks which kind of agreed that he was tracking large,” Kari said.

Lewis’ predicted size barely fazed the second-time mum.

“I suppose in some ways I was thinking how am I going to do it but towards his due date I was feeling quite positive about the birth and I just thought it’ll just be what it’ll be, and you know, as long as everyone’s happy and healthy,” Kari said.

Her outlook was spot-on as Lewis was born on his due date and his birth required no intervention such as a C-section or epidural.

However, Kari said the couple were lucky to make it to the hospital in time.

That morning she thought she was in labour. She called her husband William home about midday.

However, the action “just petered off”. Even a walk couldn’t keep the momentum going, Kari thought.

Convinced it was a false alarm, she took a nap.

“Then around 6pm it started ramping up again – quite quickly.”

They phoned their midwife at 7.30pm, arrived at the hospital just after 8pm and at 8.29pm Lewis was born.

“Within 25 minutes of being there he was in our arms,” Kari said.

Newborn Lewis Muller tipped the scales at 13lb 6oz.

Family and friends were surprised by how much Lewis weighed, with none knowing of parents who’d had a 13lb 6oz baby.

The midwife told the Mullers Lewis was her first 13lb delivery.

Kari said Lewis, who had been 61cm long, had skipped newborn clothes and already fitted snuggly into size zero to 3 months.

“He’s very sleepy and chill,” William said of his newborn son.

Kari Muller with husband William, son Walter (left) and new addition Lewis.

The Muller boys seemed to take after their parents, as Kari weighed 10lb (4.54kg) at birth and William 11lb 6oz (5.13kg).

On February 19, a Whanganui family welcomed their newborn son, who weighed about double the average birth weight at 15lb 3oz (6.89kg).

The birth of a 16lb (7.39kg) baby was reported by the NZ Herald in 2017 and is thought to be the New Zealand record.