Subdiagnóstico de restricción de crecimiento fetal mediante la aplicación de las curvas de crecimiento intrauterino del Ministerio de Salud / Under diagnosis of fetal growth restriction by the new growth curves of the Chilean Ministry of Health

ABSTRACT

Background: Fetal growth restriction (FGR) is associated with increased risk of perinatal morbidity or death. Nationwide implementation of new fetal growth charts, requires a lower fetal weight for the diagnosis of FGR, compared to previous ones. This may lead to an under diagnosis of FGR in a large proportion of neonates. Aim: To compare the morbidity, mortality and anthropometry of neonates with FGR, diagnosed by MINSAL and Juez curves, with normal weight newborns in the same period (2000-2004). Material and methods: Revision of medical records of all births occurring in a maternity hospital between 2000 and 2004. The number of neonatal deaths, and the presence of hyperbilirubinemia, polyglobulia, hypoglycemia and hypothermia, were compared among children classified to be below percentile 10 of fetal growth according to both growth charts. Results: FGR was diagnosed in 4,4 percent (502/11.289) and 9 percent (1.029/11.289) of newborns by MINSAL and Juez curves respectively. Compared to normal weight controls, the 527 newborns without FGR according to MINSAL curves, but below percentile 10 of Juez curves, had an odds ratio (OR) for polyglobulina of 8.14 (95 percent confidence intervals (CI) 1.01-65.34), an OR for neonatal hypoglycemia of 5.10 (95 percent CI 1.11-23.39) and an OR for a ponderal index below 10th percentile of 10.98 (95 percent CI 6.84-17.64). Conclusions: Newborns without a diagnosis of FGR by MINSAL curves but below 10th percentile by Juez curves, have neonatal outcomes suggesting a true FGR. Juez curves should be maintained as a standard for the evaluation of fetal growth in our population.