Gestational diabetes and fetal macrosomia in a multi-ethnic population

We set out to examine maternal and neonatal factors surrounding increased birthweight in a multi-ethnic population having an increased prevalence of diabetes mellitus. Additionally, to document the difference (if any) for such neonates in rates of obstetrical operative intervention at delivery where a specific diagnosis of maternal gestational diabetes mellitus had been made. This was an observational study of unselected mothers giving birth to a neonate of 4000 g or more. Data for this population concerning the results of antenatal screening and diagnostic testing for gestational diabetes mellitus were available as a subset of a larger independent and ongoing database. Odds ratios were used to compare group attributes subset on ethnic, diabetic screening and diabetic diagnostic status. Two ethnic groups showed an increased odds ratio for increased birthweight. A diagnosis of diabetes was associated with a twofold increase in caesarean section rare, and a significant increase in median birthweight when compared with screen positive/diagnostic negative mothers. A total of 70.4% of mothers were overweight or obese while neonatal ponderal index showed a dependence on birthweight (r² = 0.17). We conclude that ethnic status is an important factor in assessing fetal size, as is maternal body mass index. A diagnosis of diabetes mellitus confers an increased risk of operative intervention at delivery. Our approach to the use of birthweight data requires re-assessment.