A study has shown that maternal obesity is a stronger
predictor of a large-for-gestational-age infant than maternal
hyperglycemia [38] . In the HAPO study [37], the
investigators found that the frequency of macrosomia in
GDM was increased by 50% compared to non-GDM in
both the nonobese and obese groups. Obesity was associated
with a 2-fold higher frequency of macrosomia whether
in the non-GDM or GDM group. Macrosomia in GDM
only was present in 26%, in GDM plus obesity in 33% and
in obesity only in 41%. A large prospective study from
Spain found that the upper quartile of maternal BMI was
responsible for 23% of macrosomia, while GDM accounted
for 3.8% [39] . Women who did not have GDM but who
were obese had a 13.6% increased risk of macrosomia (defined
as a child weighing 4,000 g or more at birth) than
nonobese women