The Dionne quintuplets in bed with their mother, Olivia Dionne, in their farmhouse in Callander, Ontario, on May 28, 1934. (Canadian Press)

The birth of octuplets in California in January 2009 was only the second time in history that eight babies born at the same time have survived more than a few hours, doctors said.

The mother gave birth to six boys and two girls weighing between one pound, eight ounces and three pounds, four ounces, said doctors at Kaiser Permanente Bellflower Medical Center near Los Angeles.

The hospital had scheduled a caesarean section for seven babies, but doctors said they were surprised when an eighth came out.

In January 2008, the birth of sextuplets at a Vancouver hospital marked the first time a set of six babies has been delivered in Canada.

Once an extremely rare phenomenon, fertility treatments have made multiple births slightly more common today. But conceiving sextuplets without the use of fertility treatments is extremely rare. In fact, the odds of giving birth to sextuplets spontaneously are one in 4.7 billion.

The grandmother of the octuplets in Los Angeles told reporters that her daughter had fertility treatments in order to conceive. It's not known whether fertility treatments were involved in the Vancouver births.

The birth of sextuplets has only been recorded approximately 160 times worldwide and few sets survived in full. Currently, the U.S. is home to six sets of sextuplets, all of which are surviving.

Twins are the most common form of multiple birth and can occur naturally once in every 90 births. The odds increase for triplets and other multiple births, according to Multiple Births Canada.

Spontaneously these births occur in Canada:

• Once in 8,100 births for triplets.
• Once in 729,000 births for quadruplets.
• Once in 65,610,000 births for quintuplets.

In recent years, the incidence of multiple births in Canada is on the rise due to the increased use of fertility drugs. It is estimated that 60 per cent of triplets, 90 per cent of quadruplets and 99 per cent of quintuplets are the result of these treatments.

Below is a timeline of some of the more publicized multiple births in Canada and across the world.

Jan. 26, 2009: Octuplets born in California were the second time in history that eight babies born at the same time have survived more than a few hours, doctors said.

Jan. 7, 2007 A woman gives birth to sextuplets in Vancouver resulting in Canada's first set of sextuplets. The babies were born at just 25 weeks into the mother's pregnancy. Two later died.

July 28, 1999 In Saskatoon, the Gilmour family welcomed Canada's eighth set of quintuplets with the assistance of infertility treatments. Originally, six babies were conceived, but one died in the womb, leaving only five.

Dec. 8-20, 1998 Octuplets were born to Nkem and Ike Chukwu in Houston, Texas, over a span of 12 days. The eldest baby was born on Dec. 8, but doctors stopped the delivery to give the remaining seven more time in the womb. The rest of the set was born on Dec. 20. A week later, the smallest of the babies died. According to the Guinness Book of World Records, the first set of octuplets was born in Sydney, Australia, in 1971, although none of the babies survived.

Jan. 14, 1998 The Humair septuplets made headlines when they were born in Abha, Saudi Arabia, not only because they were the second set of septuplets ever recorded, but also because they were born to a 40-year-old mother.

Nov. 19, 1997 Born nine weeks premature, the McCaughey septuplets became the world's first set of seven to survive. Bobbi and Kenny McCaughey became the proud parents of the septuplets by way of fertility drugs.

May 25, 1993 Holding the title of the first sextuplets born in the U.S., the Dilley sextuplets were delivered in Indiana. The four boys and two girls were conceived using an infertility treatment called Pergonal.

Nov. 11, 1983 The United Kingdom received its first set of sextuplets when the Walton babies were born in Liverpool.

Jan. 11, 1974 The first known sextuplets were born in Cape Town, South Africa, to Susan and Colin Rosenkowitz.

May 28, 1934 Canada's most famous multiple birth, the Dionne quintuplets, were delivered in a northern Ontario farmhouse. The set would become known internationally during the Great Depression and become a tourist attraction. The quints were the world's first set to survive through infancy and were born naturally before the advent of fertility treatments.

Jan. 4, 1915 The Keys quadruplets were born in Oklahoma and would grow to become the first all-female set to survive infancy and carry on into adulthood.