• Measurement
• Neonatology
• Obesity

Babies of 4 kg or more at birth—‘big fat babies’—tend to get a bad press. There are several reasons for this. That they are more likely to have a difficult time squeezing themselves down the birth canal is well known and unsurprising, hence their increased rates of shoulder dystocia and clavicle fracture. But they also get caught in the wake of infants of diabetic mothers, which are also big fat babies, and which historically have had a variety of problems attributed to them: polycythaemia, hypocalcaemia, hypoglycaemia, and a propensity for respiratory distress, among others. Babies who either by virtue of their genetic endowment or for no particular reason are merely large can thus suffer investigations and potentially unnecessary treatments, because ‘everyone knows’ that these are dodgy babies who should be treated as if they were infants of diabetic mothers.

Therefore, it is important that Linder et al,1 in their paper, have tackled this belief system. Their data are important on several fronts. Most strikingly, the numbers are very large: from a base population of over 60 000 they had nearly 2766 ‘macrosomic’ infants of 4 kg or more, who were not infants of diabetic mothers, and compared these with an equal number of controls; all collected over 10 years. They present anthropometric data on their subjects, which allows …