Relationship of Glycosylated Hemoglobin, Fetal Macrosomia, and Birthweight Macrosomia

ABSTRACT

Previous studies have shown that glycosylated hemoglobin (Hb A_1C) once elevated correlated with fetal malformations, poor perinatal outcome, and macrosomia. To determine whether Hb A_1C was related to fetal diabetic complications such as polyhydram-nios, fetal macrosomia, and fat line detected on ultrasonographic evaluation, 66 diabetic patient, types I, II, and III, were followed longitudinally. These ultrasound markers were further assessed regarding the reliability of predicting birthweight macrosomia. Fetal macrosomia and birthweight macrosomia were defined by weight greater than the 90th percentile for gestational age based on the Williams growth curve. The Hb A_1C values were compared to women with and without fetal diabetic complications. Fetal diabetic complications occurred in 13 (20%) of the cases and birthweight macrosomia occurred in 19 (29%) of the cases. Of those 13 women with fetal diabetic complications, 11 (85%) had Hb A_1C greater than 6.3%. This level was significantly different in women with the ultrasound markers vs those without. Ultrasound-determined macrosomia in predicting birthweight macrosomia has a sensitivity, specificity, positive and negative predictive values of 53%, 94%, 77%, and 83%, respectively. There is a critical level of Hb A_1C at which ultrasound fetal diabetic markers were observed; this level is greater than 6.3%. We conclude that there is a target level of glycemic control that one must avoid to prevent birthweight macrosomia.

Keywords

Diabetes - glycosylated hemoglobin - macrosomia