[Nutrition assessment during pregnancy. A new weight chart].

Weight charts and patterns of weight gain for pregnant women in Argentina are scarce. The aims of the study were: 1) to design a new reference weight gain chart to asses the nutritional status of pregnant women using the body mass index (BMI); 2) to estimate weight gain patterns, and 3) to compare it with a proposed reference chart. In 326 pregnant women before 16th week gestation at enrollment during 2001-2002 at the Sarda' Maternity Hospital (Buenos Aires), weight, height, mid arm circumference and skinfold were measured and body mass index was calculated. Mean, standard deviation, coefficient of variation and polynomial percentiles 3rd through 97th were generated for each gestational age between 12th to 42nd weeks. Maximum variability was 18.4% after 28th week, mean preconcepcional BMI was 24.2 +/- 4.5 kg/m2 and 96% of newborns were at term with a mean Ponderal Index of 2.7 +/- 0.2 g/cm3. Trimesters weight increments were 0.600 kg +/- 0.473, 6.476 kg +/- 3.739 and 5.388kg +/- 4.233 for the 1st, 2nd and 3rd, respectively. Total weight gain achieved was 12.46 Kg +/- 3.13. Compared with the reference curve, the new one showed concordance at the 50th percentile with the upper limit of the normal range. The new reference charts of weight gain for pregnant women using maternal weight and BMI may be useful in prenatal care to asses nutritional status during pregnancy.