Timing of fetal growth acceleration in women with insulin-dependent diabetes.

OBJECTIVE

To detect differences in growth profiles of fetuses of type 1 diabetic mothers, aiming at finding when growth acceleration happens in large-for-gestational-age (LGA) fetuses at birth as compared with appropriate-for-gestational-age (AGA) fetuses and the relationship between growth profile and diabetic control throughout pregnancy.

METHODS

Ninety-eight mother-infant pairs with well-controlled insulin-dependent diabetes were included. The fetal abdominal circumference was measured every 3 weeks by ultrasound between 20 and 36 weeks' gestation. Metabolic control was evaluated by monthly measurement of glycated haemoglobin concentration and weekly measurement of the capillary blood glucose levels.

RESULTS

A significant difference in fetal abdominal circumference was detected at 24 weeks. The fetuses in both the LGA and the AGA groups were able to maintain their growth profile (i.e., accelerated or normal growth) throughout pregnancy. The parameters of glucose control were similar for both groups at any gestational age.

CONCLUSIONS

Fetal growth acceleration is identifiable by ultrasound at about 24 weeks. 'Normal' parameters of glucose control during the 1st trimester and throughout pregnancy do not seem to be related to the growth potential of the LGA fetus of a diabetic mother. Fluctuations in glucose levels rather than basal levels are probably more determinant in fetal growth acceleration.