Objectives: The gestational weight gain chart published by Rosso and Mardones (RM) was used by the Ministry of Health in Argentina from the 1990s until 2009, when it was replaced by the Calvo et al. chart (CEA). This study compared the diagnostic capability of the RM and CEA charts for identifying mothers at risk of delivering babies with signs of intrauterine growth impairment (Birth length<50 cm, Birth weight <2500 g, Birth weight <3000 g and Birth weight >4000 g).
Methods: Data from pregnant women and neonates studied in Santiago, Chile (n = 27,600), as well as a sub-sample of 11,465 term healthy singleton cases were utilized. Frequency distributions of women and their 95% confidence intervals were calculated for both charts at the first and third trimester of pregnancy. Sensitivity, specificity, positive and negative predictive values of undesirable outcomes of the RM and CEA charts were compared.
Results: The CEA chart classified as either underweight or obese a smaller number of women than the RM chart. The proportion of neonates with signs of intrauterine growth impairment was similar in both charts, however the number of affected neonates was higher in the women considered to be either underweight or obese by the RM chart. Higher sensitivity values for undesirable outcomes were displayed by the RM chart. The sum of sensitivity and specificity was also higher for the RM chart, meaning a greater diagnostic accuracy; this sum was comparable only for birth weight <2500 g. The RM chart was found to have higher positive and negative predictive values for undesirable outcomes than the CEA chart.
Conclusion: The RM chart has a better diagnostic capability than the CEA chart to identify mothers at risk of delivering babies with signs of intrauterine growth impairment.