Fetal macrosomia in Japanese women

It is unknown how to reduce the number of macrosomic neonates among women without hyperglycemia. The aim of this study was to determine clinically useful risk factors for macrosomic neonates among women without hyperglycemia.

A retrospective observational study was conducted in 117 680 Japanese women without hyperglycemia who gave birth to singleton infants at 37 weeks of gestation or later. Maternal age, parity, fetal sex, pregnancy length, and maternal body composition were studied as possible candidates for risk factors of macrosomic neonates using multivariate logistic regression analyses. Outcome measures were clinically available independent risk factors for macrosomic neonates weighing 4000 g or more.

A total of 1037 (0.9%) women gave birth to macrosomic neonates. A male fetus (odds ratio [95% confidence interval]: 1.99 [1.75-2.27]), multiparity (1.75 [1.53-1.99]), pregnancy length of 41 weeks or more (4.28 [3.73-4.91]) and six characteristics at or above the 90th percentile values consisting of body height (≥1.65 m: 1.70 [1.45-1.99]), pre-pregnancy body weight (≥65 kg: 1.47 [1.12-1.93]), pre-pregnancy body mass index (BMI) (≥25 kg/m²: 1.49 [1.16-1.91]), weight gain during pregnancy (≥15 kg: 2.32 [1.78-3.03]), BMI gain during pregnancy (≥6.0 kg/m²: 1.52 [1.16-2.00]), and body weight at delivery (≥75 kg: 2.57 [2.08-3.17]) were identified as independent risk factors for macrosomia.

Intervention, such as a counseling on dietary habits leading to a lesser net weight gain may be considered among women suspected of having fetal overgrowth.