Einstein (São Paulo) (Dec 2008)
Intrauterine growth curve for newborns of the city of São Paulo, Brazil
Abstract
Objective: To construct an intrauterine growth curve for a populationof a large city based on existing data. Methods: Based on the LiveNewborn Registry from 2004, for the city of São Paulo, birth weightdistribution according to gestational age was analyzed. Twinbirths as well as newborns with congenital malformation or thoselacking the information on birth weight or gestational age wereexcluded. The Curve Expert 1.3 software was used to plot birthweight for gestational age, estimating the 3rd, 10th, 50th and 90thpercentiles. From these values, an equation of “weight/gestationalage” equivalence was established, estimating percentile values fornewborns with gestational ages between 22 and 42 weeks, andthus constructing the curve for the proposed percentiles. Results:The final sample comprised 189,990 newborns. The mean birthweight for gestational age of less than 22 weeks was 535.25± 114.7 g; for 22 to 27 weeks, 825.43 ± 232.8 g; for 28 to 31weeks, 1,351.13 ± 364.09 g; for 32 to 36 weeks, 2,452.75 ±520.71 g; for 37 to 41 weeks, 3,223.37 ± 415.20 g; for > 41weeks, 3,438.16 ± 505.18 g. The weight values for 22 and 42weeks for the third percentile varied from 343.80 to 2,625 g; for thetenth percentile, from 371.35 to 2,836.67 g; for the 50th percentile,from 562.17 to 3,402.98 g and for the 90th percentile, from 778.72to 4,032.45 g. Conclusions: A specific intrauterine growth curvefor the population of the city of São Paulo was constructed fromthe weights recorded in an official database. The construction ofthe third percentile enables targeting proper healthcare to smallnewborns for gestational age, as well as identifying those whoshould receive care beyond the neonatal period.
