Ethnic differences in antepartum glucose values that predict postpartum dysglycemia and neonatal macrosomia

Gestational diabetes (GDM) occurs more often in women from certain ethnic groups and is also associated with fetal macrosomia. In this study, we investigated the ability of a gestational diabetes screening test (GDS), the 2 h 75 g-Oral Glucose Tolerance Test (OGTT), and glycated hemoglobin (HbA1c) in predicting postpartum dysglycemia and fetal macrosomia in women of Caucasian, Filipino, Chinese and South-Asian descent.

848 women diagnosed with carbohydrate intolerance in pregnancy who completed a 2 h 75 g- OGTT within 6 months postpartum, were included in the study. Receiver Operating Characteristic curve analysis was used to test the ability of antepartum GDS, HbA1c and OGTT in predicting postpartum hyperglycemia, type 2 diabetes (T2D) and neonatal macrosomia (birth weight >4000 g).

20.2% had postpartum hyperglycemia while 3.8% had T2D. Those with postpartum dysglycemia were more likely to be non-Caucasian (South-Asian > Filipino > Chinese), have higher antepartum glucose values, require insulin during pregnancy and have cesarean births. Of HbA1c and the antepartum glucose values, a fasting glucose of ≥5.25 mmol/L was predictive of fetal macrosomia in Caucasians. 1 h glucose of ≥11.05 mmol/L was predictive of postpartum hyperglycemia, while 2 h glucose of ≥9.75 mmol/L was predictive of T2D; ethnicity influenced the predictive ability of these tests.

Ethnicity influences the ability of antepartum glucose and HbA1c to predict the risk of macrosomia and postpartum dysglycemia. This information will help detect those most at risk of T2D.