If you believe the current ill researched frenzy in the UK media at the moment you will probably think it is because we all eat too many chips. In reality there's an awful lot more to it than that.

It is true that women who develop Gestational Diabetes are more likely (a twofold risk in fact) to give birth to a larger infant, however this site is interested in those women who have not been labelled with any medical disorder and who seem to "just make big babies".

There are several known risk factors, aside from Gestational Diabetes, which can highlight certain women who are more predisposed to birthing a macrosomic baby, these are:

1) Multiparity (not your first baby)
2) Birthing a previous macrosomic baby
3) A prolonged period of gestation
4) Carrying a male baby
5) Parental Stature
6) Excessive weight gain during pregnancy

Genetics does seem to play a role though and often women will give birth to a very large baby with none of the above risk factors - in fact according to Boyd, Usher & McLean and their report "Fetal macrosomia: prediction, risks, proposed management" - 34% of macrosomic babies are indicated to be born to mothers with NO risk factors! similarly very obese women are just as likely to deliver smaller infants. Finally even with TWO of the above risk factors present, women are only 32% likely to have a macrosomic infant.

  So it seems we can eat the odd bag of chips in peace after all!