While serum fructosamine may be a good marker of glucose control in pregnant women with diabetes, its relationship with macrosomia is still uncertain.

In 130 hyperglycaemic women with singleton pregnancies (117 gestational diabetes mellitus, 13 pregestational diabetes), serum fructosamine and HbA1c levels were measured at 25±7 weeks of gestation. Levels in mothers of infants with and without macrosomic newborns (birth weight>4000g and/or large-for-gestational-age birth weight>90th percentile) were compared using logistic regression analysis adjusted for macrosomia risk factors.

These 130 pregnant women were 33±5 years old; their BMI before pregnancy was 27.7±6.9kg/m², and they gained 7.5±5.1kg during the first 6 months of gestation. Glucose control was good according to HbA1c levels (5.3±0.3%; 34±2mmol/mol), yet 17/130 (13%) newborns had macrosomia: 3900±227g vs 3057±512g (P<0.001) in the others. These mothers were older and had higher parity, whereas their BMI scores before pregnancy and gestational weight gains did not differ. Fructosamine levels were also higher at 221±40μmol/L vs 192±22μmol/l (P<0.001), respectively, and remained significant even after adjusting for maternal age, BMI, parity, type of diabetes, antecedents of macrosomia and excessive gestational weight gain. By contrast, HbA1c did not differ between the two groups. In fact, nearly two-thirds (64.7%) of the mothers of macrosomic newborns had fructosamine levels>200μmol/l vs 31.9% of mothers with non-macrosomic newborns (P<0.05).

High fructosamine levels are associated with macrosomia in the newborns of well-controlled hyperglycaemic pregnant women.