Evaluation of the Cut-off points proposed by IOM in assessing nutritional status in Chilean pregnant women: impact on the prevalence, in the evaluation of adequate gestational weight gain and in neonatal outcomes

Abstract

Objective: Evaluating the impact of adopting cut-off points recommended by the Institute of Medicine (IOM) for classifying nutritional status (NS) as underweight (UW) and normal (N) in Chilean pregnant women versus the standard used in Chile (Minsal standard), on i. prevalence of NS, ii. the evaluation of adequate gestational weight gain (GWG) and iii. neonatal outcomes (NO). Design: Data from clinical records of the universe of pregnant women attended during 2003-2012 at the Hospital Sótero del Río were collected. For each standard four analysis were carried out, 1.NS prevalence, 2.GWG 3.Association between NS and NO, using logistic regression models, and 4.Sensitivity, specificity, and predictive values in UW versus N women and the effects in NO. Setting: Representative population of women in the South East Area of Santiago, Chile. Subjects: Single birth pregnancies (n=59,476). Results: With the IOM cut-off points pre-pregnancy UW decreased from 8.6% to 2.5% in the whole sample and from 16.8% to 5.3% among adolescents. Moreover, women with a BMI between 18.5-19.9kg/m2 who exceeded the recommended GWG increased from 33% to 50%. The IOM cut-off point showed better specificities when detecting adverse NO than the Minsal standard (e.g. for small for gestational age newborns in underweight: 95.6% vs. 84.7%). Associations between NS and adverse NO were slightly higher using the IOM standard, but these differences were not statistically significant (p>0.05). Conclusions: The proposed IOM cut-off points may be a useful tool to evaluate NS for the prevention of excessive GWG without increase in the incidence of adverse NO.