Study On The Influencing Factors And Reference Values Of Neonatal Head Circumference

ObjectiveTo explore the influencing factors of neonatal head circumference and evaluate the applicability in this sample of three reference values of 15 cities in China in 1986(hereinafter referred to as 15 cities),Beijing in 2015(hereinafter referred to as Beijing)and Shenzhen in 2017(hereinafter referred to as Shenzhen),and to establish a normal reference values of neonatal head circumference for providing a basis for timely and accurate identification of microcephaly in Zika virus infection.MethodA sample of maternal and neonatal information was collected through the hospital electronic medical record system from January 2014 to December 2017 in Guangdong Maternal and Child Health Hospital.The risk factors of birth head circumference were analyzed by independent sample t test/variance analysis and multifactor generalized linear regression analysis.Kappa test was used to analyze the consistency of three normal reference values of head circumference with the study samples,and Yoden index was used to evaluate the accuracy of these three reference values in screening microcephaly.GAMLSS method was used to fit data and establish percentile reference values and curves.Residual parameter table and residual Q-Q plots were used to evaluate the fitting effect comprehensively.13707 neonatal information samples were randomly sampled to form a validation sample.Chi-square test was used to compare the sensitivity of reference values of this study with those of the 21st century international standards for neonatal head circumference,Canadian reference values,American reference values,Gennan reference values,15 cities,Beijing and Shenzhen(hereinafter referred to as the 21st century,Canada,the United States,Gemany)to detect suspected microcephaly in the validated samples.Results1.A total of 48928 cases of neonatal-mother medical record information were analysed about influencing factors.The mean head circumference of neonates was(33.41.7)cm,The head circumference of exposure to term infant,cesarean section,male newborns,hydramnios and older pregnant women,neonates whose ancestral homes were from northern provinces of China,multiple pregnancy,multiparity,gestational diabetes mellitus were bigger(P<0.05).And the head circumference of exposure to intrauterine growth restriction,umbilical cord around neck,umbilical cord torsion,oligohydramnios and maternal pregnancy complicated with hypertension,cholestasis,anemia were smaller(P<0.05).There were no significant differences in head circumference among neonates with abnormal structure,assisted reproductive,amniotic fluid characteristics,maternal thyroid function,scarred uterus,placenta previa and reproductive tract infection(P>0.05).2.The reference values of 15 cities in China are closer to the measured values of boys and full-term infants,Beijing reference range is closer to the measured values of girls in this study,and Shenzhen reference range is closer to the measured values of actual premature infants in this study.The overall accuracy of the three reference values in identifying microcephaly is high,but grouping by gestational age,it is found that the accuracy of the reference values of 15 cities in China and Beijing in identifying microcephaly in premature male newborns is low3.A total of 27145 cases of neonatal information were used to establish the normal reference values of neonatal head circumference.There was no significant difference in gender between 25 and 31 weeks,33 weeks and 42 weeks of gestational age(p>0.05),and no significant difference in parity between 25 and 32 weeks of gestational age and 42 weeks of gestational age(p>0.05),There were significant differences in gender and parity among other gestational ages(p<0.05).Normal head circumference percentile reference values and percentile curves in 25-33 weeks and 34-42 weeks gestational age of male/female neonates delivered by primipara/multiparous women of different gestational ages(hereinafter referred to as primipara/multiparous)were established respectively.4.In the 25-36 week gestational age,except for the difference of sensitivity in detection rate of microcephaly between the group of male delivered by pluripara and the group of Canadian males,there was no significant difference in other groups.At 37-42 weeks of gestational age,the sensitivity of microcephaly by using the reference values of 21 century,Canada and Germany were higher than those of results in this study.The sensitivity of the reference value of primipara in male neonates with microcephaly was higher than that in the United States and Beijing.There was no significant difference between the other groups.Conclusion1.The neonatal head circumference is affected by many factors.In formulating the reference range of normal birth head circumference,we should exclude samples of related disease factors,,besides considering the differences of physiological factors.It proves the scientificity of the reference range.2.By analyzing the applicability of the three reference values in this neonatal population,it is found that the three reference values of neonatal head circumference have some limitations for evaluateing accurately.Therefore,it is necessary to establish a reference range of head circumference for local neonates.3.According to the characteristics of head circumference at different gestational ages,using GAMLSS method to construct the percentage reference values of different parities and sexes are more accurate,to providea basis for identifying the microcephaly in Zika virus infection.