Polock index of 16 887 singleton neonates in different gestational age in Shenzhen City

Abstract

Objective To establish the Polock indexes (PI) of singleton neonates in different gestational age (GA), so as to provide a reference data for evaluating physical fullness and symmetry in neonates at birth. Methods A total of 16 887 live singleton neonates at 27-42 weeks of GA from two hospitals were measured at birth by site survey method using cluster samples by a cross sectional time in Shenzhen City, from 2013 to 2015 in this study, to establish PI of singleton neonates in different GA. Results The PI mean and the percentile curves(3rd, 10th, 25th, 50th, 75th, 90th, 97th )of singleton neonates at 27-42 weeks of GA (male, female, and unisex three groups) were established in 2015 in Shenzhen, China.The fullness and nutrition status of neonates at birth can be evaluated by these PI curves.According to the 3rd, 10th, 25th-75th, 90th, 97th curves, the down, mid down, middle, mid upper, upper levels were divided in turn.When the PI values>97th curve it was overweighted or fatty.When the PI values<3rd curve it was malnutrition.The lowest values of PI were at 27 weeks of GA, and the highest values appeared at 42 weeks of GA.The PI values were increasing with GA growth, which indicated that the GA increased the body density and fullness.The 50th percentile curve of male PI was higher than that of the female, and the male ratio increased by 61.2-89.5 at the gestational age of 27-34 weeks; between 35 and 42 weeks of fetal age, males increased by 104.8-149.1, which had a statistical difference (P<0.001). Conclusions The PI of singleton neonates rises with GA increase, which shows the GA increases the body density and fullness.PI is higher in male than in female singleton neonates. Key words: Different gestational age; Singleton; Infant, newborn; Polock index