The upside to being an older mother was that Mrs Stewart and her husband, Rex, already had their finances sorted.
"I've probably got my head screwed on a bit straighter than if I was a bit younger," she said.
The 2013 births and deaths figures, released yesterday by Statistics NZ, showed Bay mothers gave birth to 3695 babies last year, nearly 200 fewer than the previous year.
While the number of deaths fell nationally, the number of people who died in the Bay region rose slightly to 2237.
The trend towards older child-bearing across the country continued, with women aged 35 to 39 having more babies than women aged 20 to 24 for the first time, Statistics NZ said. Women in the 30 to 34 age bracket had the highest fertility rate.
Bay of Plenty lactation consultant Trudy Hart said many local women were waiting until their late 30s to start having children.
"They can enjoy a life, [they feel] their careers are much more important than being mothers and then they encounter infertility because they're leaving it too late.
"It is certainly a trend."
According to Statistics NZ, Kiwi mothers gave birth to 58,717 babies last year - a 4 per cent drop from 2012.
Death numbers also fell slightly to 29,568 last year.
New Zealand's natural increase - live births minus deaths - was the lowest since 2003.
University of Otago sociologist Bryndl Hohmann-Marriott said the rise in the number of older mothers was a continuing trend. "New Zealand actually has one of the oldest ages of first birth in the developed world."
Once considered high-risk, births in the 35-39 age bracket were now better managed - and more common.
Despite the slowing birth rate, the number of babies born here was still high compared with other developed nations, she said.
But a European trend towards fewer children could catch on here, Dr Hohmann-Marriott said.
"In a lot of those European countries like Italy, Spain and Germany where they're having so few children, people just don't want them anymore.
"For the first time there's a huge number of people who don't want any children at all. It's so difficult and so expensive to have [children]."
Slowing birth rates in Europe could largely be attributed to changing lifestyle priorities and the global financial crisis, she said, with uncertainty putting people off having kids.
New Zealand's housing shortage could also be influencing people's decisions, she said.
Statistics NZ analyst Anne Howard said fluctuations in birth rates could be a "challenge" for planners and schools.
"When you look at 2008 when we had 64,343 births, and now we've got 58,717, that's quite a big difference when you start working out the numbers of teachers and class sizes," she said. "It certainly has implications for education and service providers."
- additional reporting Amy McGillivray
