Australian babies are getting bigger, with the average newborn now weighing on average 3.5kg, up from 3.3kg in 2005.
* Mothers are getting older;
* Lifestyle factors such as obesity and diabetes;
* Increase in the use of fertility treatments;
* Reduction in maternal smoking;
* Ethnicity of Australian mothers has changed.
It's thought the increase in newborn baby weight is leading to an increase in caesareans. If this is the case, it is an issue because caesareans carry risks. Also large babies can suffer health problems of their own.
Mary Helen Black, a biostatistician with Kaiser Permanente Southern California's department of research and evaluation explained to the Huffington Post in an interview last year that babies who are born too large are at an increased risk "for very serious consequences both during delivery, for the mother and the infant, as well as later in life for the infant."
Incidents of very big newborns are known as fetal macrosomia and any baby above 8 pounds, 13 ounces (3.9kg) qualifies.
Dr. Sheiva Ghofrany from Stamford Hospital told the Huffington Post, "babies have definitely been coming out bigger" in the past five to six years which she has attributed to rising rates of maternal obesity and diabetes.
Three recent births in the United States, Spain and Germany have totally blown the 3.9kg qualifier out of the water.
The Cessna family in Pennsylvania in the US are celebrating the birth of Addyson Gale Cessna who has weighed in at 13 pounds, 12 ounces (6.2kg).