More Canadians, it seems, are changing dirty diapers, serving up spoonfuls of mushy peas and getting tongue-tied over Dr. Seuss books before bed, if the latest census figures from Statistics Canada are any indication.

The number of children in Canada aged four and under jumped 11 per cent between 2006 and 2011 — the highest rate of growth for that age group since the five years between 1956 and 1961, the trailing edge of the baby boom, census numbers released Tuesday show.

And though the increase pales in comparison with the dramatic spike in births that followed the end of the Second World War, Canada's baby bump is definitely showing: it's the first time in 50 years that Statistics Canada has recorded an increase for that age group in every province and territory.

"I love being a mom," said Erin Koestlmaier, a mother of three in Edmonton. "Even when I was a little girl, I loved kids and babysitting and I always knew I was going to be a mom."

The 33-year-old runs her own business called Fit Mommy, teaching "strollercize" — working out while pushing a stroller — and boot-camp workouts to women who want to lose their baby weight or generally keep in shape.

To keep up with more mommy demand, she'll soon be adding another class to her schedule.

Koestlmaier said her clients are mostly first-time moms, although some have several children. She's currently negotiating with her husband, Mike, about the size of her own family.

"He's not necessarily on board, but I'd like to go for a fourth," she said with a laugh.

Previously released population statistics show more people in Canada are having children. The national birth rate increased slightly from 1.59 in 2006 to 1.67 in 2009. In Alberta, the rate is among the highest of the provinces; it was 1.8 in 2010.

Not surprisingly, the latest increase was felt most profoundly in the Prairies, which have become magnets for job-seeking, working-age families looking for a place to put down roots. In Alberta, the growth rate among kids four and under was 20.9 per cent, followed by Saskatchewan at 19.6 per cent.

Quebec also posted a strong increase at 17.5 per cent, as did Nunavut at 15.7 per cent.

Grandchildren of baby boomers

Another reason for Canada's baby bump may simply be that there are more moms. Statistics Canada attributed the spike to modestly higher fertility rates in most regions, as well as a growing number of women aged 20 to 34 — traditional child-rearing years.

'These echo boomers, now in their early 30s, are starting their own families.'—David Foot, author of Boom, Bust and Echo

"This is the main reason for the increase," said David Foot, an economics professor at the University of Toronto and co-author of the 1996 bestseller, Boom, Bust and Echo, which explored how demographics can explain economic trends.

The spike in small children is the result of the children of baby boomers — the so-called "echo" — having kids of their own, Foot said.

"These echo boomers, now in their early 30s, are starting their own families," he said. "These are the boomers' grandchildren being born."

Roderic Beaujot, a demographer at Western University's Centre of Population, Aging and Health in London, Ont., said while "pure demographics" is behind the increase, other factors could be in play as well.

For years, women have been choosing to have children later in life, spending more time in school, starting careers and establishing personal relationships. Now, they're starting families.

"In some sense, the delay is coming to an end," Beaujot said. "Because you can't delay much more."

Beaujot also said he suspects more working women are choosing to have children. The fertility rate went into a nosedive after the baby boom, and experts attributed the decline to more women joining the workforce.

"Women were doing more paid work, so they didn't have time to have children," Beaujot said. "Having children has become more positive."

More confident about decision to have kids

Provinces with more working women now tend to have higher fertility rates, he added. Women are feeling more confident about the decision to have kids, in part because there are more government policies to support families, such as parental leave.

Quebec in particular has a landmark $7-a-day daycare program. And the federal government gives families $100 for every Canadian child under six as part of its Universal Child Care Benefit.

The Alberta government has helped create 20,000 new daycare spaces in recent years to keep up with demand — both from the province's high birth rate and the families who have been flocking to the province.

The spaces include after-school spots for older children, because many mothers who do stay home eventually go back to work, said Cathy Ducharme of Alberta Human Services.

A strong economy, especially in Alberta, is also helping fuel young families, Beaujot said.

"Young people feel confidence in the labour market. They can even withdraw from the labour market for a while, knowing that they could get a job when they go back in ... It gives them confidence so they can have children, and it's not particularly risky from an economic point of view."