The CIHI report, released Thursday, shows that more than 371,000 infants were born in hospitals in 2010-2011 — about 5,600 or 1.5 per cent fewer than the previous year.
All provinces and territories reported a drop in birth rates, except for Yukon, which had a slight increase.
"The trend really is that since 2002 we've been seeing an increase in the birth rate. And for the first time this year, our data have shown a drop in the births," said Agnita Pal, manager of acute and ambulatory care information services for CIHI.
The report does not include children born at home or in other settings, but is based on babies born in hospitals, which represents about 99 per cent of all births in Canada.
"Although the number of babies born annually decreased steadily between 1995–1996 and 2000–2001 — dropping by 13.1 per cent or about 50,000 newborns — the next nine years saw an increase in births, such that the number of babies born in 2009–2010 mirrored that in 1995–1996," the report says.
That recent drop in births seems somewhat at odds with Statistics Canada's latest census data, released earlier this year, which showed a bit of an uptick in the overall birth rate between 2006 and 2011. Some experts attribute the minor baby bump to a cohort of older moms having their first child.
"The lower birth rate is the first time we're seeing it, so we'll have to look out for it if that's an ongoing trend or a one-time thing," said Pal.
CIHI also found that the proportion of babies born prematurely, before 37 weeks gestation, has remained relatively stable since 2006-2007 at one in 12 births, although rates vary among provinces and territories.
Alberta and Ontario had the highest rates of preterm births at 8.6 per cent and 8.1 per cent, respectively. Quebec, with a preemie birth rate of 7.3 per cent, was significantly below the national rate of 7.9 per cent.
Annual caesarean-section rates for first-time mothers have remained stable over the years, with the national rate in 2010-2011 at about 18 per cent of all births.
However, there is considerable variance across the provinces and territories, said Pal.
Newfoundland-Labrador, at 23.5 per cent, and British Columbia, at 22.9 per cent, were well above the national rate, she said. Saskatchewan (14.7 per cent) and Manitoba (14.4 per cent) were among the jurisdictions recording the lowest proportion of C-sections.
"We also have Nunavut with the lowest rate at about six per cent," said Pal, noting that the World Health Organization suggests that countries with C-section rates above 15 per cent should be examining the reasons why so many are occurring.
While the report does not explore the reasons for any of its birth-related trends, Pal said a number of factors could contribute to higher caesarean rates, including maternal age and health, patient preferences and differences in physician practices.
Many C-sections are medically necessary, which the Society of Obstetricians and Gynecologists of Canada argues should be the only reason to perform the surgery.
"So the level of variance across provinces here is quite significant and something to be researched further if Canadian women are having C-sections for non-medical reasons," Pal said.
The report also shows women age 35 and older had significantly higher caesarean rates when delivering their first child than their younger counterparts, 23 per cent compared to 17 per cent.
In 2010–2011, the proportion of women opting for epidurals during labour and delivery continued to vary widely among the provinces, the report shows. About two-thirds of vaginal deliveries in Quebec (70 per cent) and Ontario (61.5 per cent) were preceded by an epidural — nearly double the rates in Manitoba (37.5 per cent) and B.C. (32.5 per cent).
Between 2006–2007 and 2010–2011, there was a significant rise — from 53.2 per cent to 56.7 per cent — in overall epidural rates for vaginal deliveries. Manitoba was the only province to see a decrease during the period, to 37.5 per cent from 38.3 per cent.
B.C. continued to have the lowest epidural rate among women having vaginal deliveries; however, the coastal province experienced the biggest increase in its rate since 2009–2010, rising to 32.5 per cent from 30.3 per cent.
The CIHI report also showed that since 1995, hospital admission rates across the country have fallen by 31 per cent.
"We don't comprehensively look at acute care use in this report, but we do know that there have been significant shifts in health-care models over the past few years," said Pal.
"For example, (many) procedures that used to require hospital admissions are now being performed as day surgeries," she said. "We know that there's been investments in health promotion, community-based programs and enhanced focus on primary health care.
"So all of these changes may be shifting the focus from hospital admission to other health-care services."