| Background and ObjectiveBirth weight is an important clinical indicator widely used for evaluating the intrauterine fetal development and evaluating neonatal health status.It is also an important indicator for reflecting the economic and social development of a country.Birth weight is closely related to the short-term and long-term health condition for newborn.For instance,low birth weight may lead to postnatal physical,mental and motor developmental delay;low birth weight also associated with obesity,cardiovascular disease and type 2 diabetes in adulthood.With the increase of the survival rate of small for gestational age(SGA)and greater than gestational age(LGA),it is accompanied by an increase in the economic burden of society and the family.How to reduce the incidence of SGA,LGA,low birth weight and macrosomia is one of the focal issues of maternal and child health care.At present,there were few studies on the comparison of birth weight between domestic and foreign,with the rapid development of China’s economy,the reference value of birth weight percentile needs to be updated in time.The purpose of this study was to understand the distribution characteristics of birth weight in newborns in Zhoushan City and Yiwu City,Zhejiang Province,and compare them with domestic and foreign studies to evaluate the basic conditions of birth weight of newborns in Zhoushan City and Yiwu City;And explore the trends of birth weight and the incidence of SGA and LGA.The reference value of birth weight percentiles was constructed,and the birth weight curve was drawn to provide a scientific basis for formulating appropriate maternal and child health strategies to prevent the incidence of abnormal birth weight in neonates.Material and MethodThis study derived the pre-pregnancy health data of pregnant women and neonatal delivery information registered from 2002 to 2018 from the electronic medical record system of Zhoushan Maternal and Child Health Hospital in Zhejiang Province.The birth registration information of newborns recorded in 2007-2018 was derived from the Yiwu Maternal and Child Health Information Platform database.The trends of neonatal birth weight change in Zhoushan City from 2002 to 2018 and Yiwu City from 2007 to 2018 was analyzed by using the segment mixed model,and the trends of adverse birth outcomes such as macrosomia,low birth weight,SGA and LGA was analyzed by Chi-square trend test.Lambda Mu Sigma method(LMS)was used to calculate the reference values of birth weight percentiles of Zhoushan and Yiwu newborns,respectively.GAMLSS model was used to draw the birth weight curve.Reference values of gestational age-specific birth weight percentiles in the "China Birth Weight Curve for Newborns of Different Gestational Ages" and the INTERGROWHT-21st study were used for comparative analysis with this study.Linear regression model was used to analyze the influence of maternal general social demographic characteristics on the birth weight of newborns.A multiple classification logistic regression model was used to analyze the association of maternal general social demographic characteristics with the SGA and LGA.ResultsThe results showed that the average birth weight of newborns in Zhoushan City from 2002 to 2018 was 3361 g,and the birth weight of boys was higher than that of girls.The birth weight of boys and girls decreased year by year from 2009 to 2011,respectively.The incidence of preterm birth,macrosomia,low birth weight,SGA and LGA in Zhoushan were 4.33%,8.60%,2.89%,5.64%and 11.46%,respectively.The incidence of macrosomia and LGA decreased year by year,while the incidence of low birth weight and SGA increased year by year.From 2007 to 2018,the average birth weight of newborns in Yiwu City was 3324 g.The birth weight of male infants was higher than that of female infants;the birth weight of male infants gradually decreased with the year,while the birth weight of female infants did not change significantly year by year;The incidence of preterm birth,macrosomia,low birth weight infants,SGA and LGA were 5.56%,7.44%,3.75%,6.13%and 10.45%respectively.The incidence of male infant’s macrosomia decreased year by year,but the incidence of low birth weight infants had no significant changes.The incidence of low birth weight and LGA in male infants and incidence of macrosomia,LGA and SGA among female infants had no significant changes.With the increase of gestational age,the birth weight was increased correspondingly.The change point of the birth weight of male and female infants appeared at 38 weeks,and the change of the birth weight of newborns with gestational age from 28 to 37 weeks was greater than that of newborns with gestational age from 38 to 42 weeks.The average birth weight of Yiwu male infants with gestational age of 37 and 38 weeks was higher than that of Zhoushan male infants with the same gestational age,while the average birth weight of Yiwu male infants with gestational age of 39 and 40 weeks was lower than that of Zhoushan male infants with the same gestational age;the average birth weight of Yiwu female infants with gestational age of 39 to 41 weeks was lower than that of Zhoushan.There was no significant difference in birth weight of other gestational age between the two cities.There was no significant difference between the birth weight of Zhoushan female infants with gestational age of 30-35 and 37 weeks and the national standard of the same gestational age in 2015.The birth weight of Zhoushan female infants with gestational age of 38-42 weeks is larger than the national standard of the same gestational age in 2015,with the median difference ranging from-102 to-25g;The birth weight of Zhoushan female infants with gestational age of 33-42 weeks was higher than that of the same gestational age female infants in the INTERGROWTH-21st study.The median difference ranged from-230 to-70g.Multivariate logistic regression analysis showed that there was no significant difference in the incidence of SGA and LGA between males and females(OR=0.94,95%CI:0.86 to 1.03;OR=1.03,95%CI:0.96 to 1.09);the birth at fall is a risk factor for SGA(1.15(1.01-1.31)),and the birth season is the protective factor for LGA in summer,fall,and winter;maternal age greater than 30 is the protective factor for SGA(0.74(0.64-0.87)),is a risk factor for LGA(1.15(1.0-1.26));Pre-pregnancy BMI less than 18kg/m2 is a risk factor for SGA(1.74(CI:1.55-1.96)),is the protective factor of LGA(0.46(0.40-0.53)).Pre-pregnancy overweight or obesity is the protective factor of SGA and the risk factor of LGA.The high level of mother’s education is the protective factor for SGA;high-risk pregnancy was a risk factor for SGA(1.44(1.25 to 1.66)).ConclusionThe birth weight of male and female infants in Zhoushan City has been decreasing year by year since 2009 and 2011,respectively.In Yiwu City,the birth weight of male infants gradually decreased with the year from 2007 to 2018,while the birth weight of female infants did not change significantly year by year.The incidence of SGA in Zhoushan and Yiwu was lower than the national standard,and the incidence of LGA was close to the national level,which implying that "most" of newborn’s birth weight in Zhoushan and Yiwu were within the normal range;this study analyzed the reference values of the birth weight percentiles of newborns in Zhoushan and Yiwu;and the birth weight curve of newborns was plotted.It provides a scientific basis for clinical practice and future analytical research.This study found that maternal age older than 30 years old,mothers pre-pregnancy overweight or obesity and other factors are risk factors for LGA;Pre-pregnancy BMI less than 18kg/m2,high-risk pregnancy were the risk factor for SGA;According to the results of this study,we suggest to that pregnant women adjust their diet and daily exercise according to their own situation,and try to avoid the occurrence of SGA and LGA. |
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