The Guardian

The number of large babies weighing 10lb or more at birth has jumped by a fifth since 2003. What is behind this boom in hefty newborns? And how has it changed pregnancy and labour? Viv Groskop talks to mothers, doctors and midwives. Sarah Ockwell-Smith, 32, a hypnobirthing teacher from Saffron Walden, Essex, knows all about larger babies. At 5ft 1in, with a 6ft husband – Ian, 38, a locksmith – she has given birth to four. Sebastian, five, was 10lb (4.53kg) at birth. Flynn, four, was 9lb 12oz. Then they got even bigger. Rafferty, now three, was 11lb 3oz and Violet, one, was 11lb. “When I was pregnant with my first baby I remember a few of the babies from my antenatal class were around 9lb. I freaked out and said to my midwife, ‘My baby is not going to be that big, is it?’ She laughed and said no, he would be about 8lb.”

The average birth weight of babies has been creeping up for the past 30 years. It is now around 7lb 8oz for boys, up 2oz from 1970, and 7lb 4oz for girls, an increase of 1.5oz, but the rise in babies with macrosomia (excessive birth weight) is more pronounced. According to figures from the Office of National Statistics, the number of babies more than 9lb 15oz increased by 20% in the decade up to 2003. According to the Guinness Book of Records the largest baby ever was born in Canada in 1879, weighing 23lb, but died 11 hours after birth.

The heaviest surviving baby was born in Italy in 1955 and weighed 22lb 8oz. A 21lb baby was born in Cornwall in 1852 and a boy weighing 20lb 2oz was born in Crewe, Cheshire in 1894. Society at large continues to find “sumo babies” hilarious. They are always an object of fascination. “I would get old ladies coming up to me in the street and saying to each other, ‘Oh my God, have you seen this one, Maureen? He was 10lb 2oz,'” says Gina Robinson, 32, a retail manager from Sheffield.

The reason babies are getting heavier is obvious, says Mervi Jokinen of the Royal College of Midwives: “It is mostly linked to better diet and living standards in the population. But big babies have always existed and sometimes it’s very difficult to say if it’s genetic or if it’s diet.” What is undeniable, however, is that obesity – of the mothers, not the babies – is a major factor. And with rising obesity rates comes an increase in gestational diabetes, which – unless carefully monitored – can increase the baby’s weight. This is a form of diabetes that occurs purely in pregnancy, usually diagnosed after 28 weeks. After pregnancy, it disappears – although it is an indicator that the patient is more likely to develop diabetes later in life. Last month the Lancet reported that diabetes worldwide is “spiralling upwards” and now affects up to 5% of pregnancies.

Of course there is that other problem with giant babies…..