Glucose tolerance in pregnancy in South India: relationships to neonatal anthropometry

Background. The incidence of type 2 diabetes is increasing worldwide, most rapidly in developing countries such as India. Exposure as a fetus to maternal gestational diabetes is thought to be a risk factor for developing the disease. This study was set up to determine the incidence of gestational diabetes mellitus in one urban maternity unit in South India and to examine its effect on the offspring's neonatal anthropometry, childhood growth, and glucose/insulin metabolism. This paper reports neonatal outcomes. Methods. Seven hundred and eighty five women were recruited consecutively from the antenatal clinic of the Holdsworth Memorial Hospital, Mysore and underwent a 100 g, 3-hr oral glucose tolerance test at 30 +/- 2 weeks gestation. Gestational diabetes was defined using Carpenter and Coustan criteria. The babies were measured in detail at birth. Results. Mean maternal age and body mass index were 23.6 years and 23.1 kg/m(2). The incidence of gestational diabetes was 6.2%. Mothers with gestational diabetes had babies that were heavier (3339 g compared with 2956 g for non-diabetic mothers) and larger in measurements of fat, muscle, and skeleton. Even in non-diabetic pregnancies, neonatal weight, head circumference, and ponderal index were positively related to maternal fasting glucose concentrations (P less than or equal to 0.05 for all). Conclusions. The incidence of gestational diabetes was high in this unselected sample of mothers booking into one urban Indian maternity unit. Community-based studies are required to confirm this. The effect of maternal glucose concentrations on neonatal anthropometry is continuous and extends into the 'normal' glycemic range.