Construction of Weight Gain Charts in a Low-Risk Obstetric Belgian Population

Aim: To generate reference charts for weight gain during pregnancy for the different BMI categories (underweight, normal weight, overweight, obesity), based on recent data in a homogeneous, Caucasian, low-risk obstetric population. Methods: Weight gain and prepregnancy BMI were retrospectively gathered from 605 pregnant Belgian women with accurately dateable, uncomplicated singleton pregnancies. Percentile curves for the different BMI categories were constructed using the linear mixed model, based on absolute weight gain. The effect of parity on weight gain was examined. Results: Overall mean weight gain was 14.8 kg (+/- 4.7). Weight gain differed significantly between underweight (15.4 +/- 4.1 kg) and obese patients (12.0 +/- 5.9 kg), between patients with normal weight (15.1 +/- 4.5 kg) and overweight patients (13.7 +/- 5.3 kg), and between normal-weight and obese patients. Parity had a statistical, but no clinically significant, influence on amount and evolution of weight gain. Conclusion: By using strict inclusion criteria, BMI-category-specific reference charts were generated representing, in terms of outcome, the optimal weight gain during pregnancy rather than the mean observed weight gain. This enables the weight charts to be used as a clinical tool during the counseling of pregnant women. Copyright (C) 2009 S. Karger AG, Basel