| Backgrounds and Objective:Extrauterine growth restriction (EUGR) affects the short-term physical growth in preterm infants, more importantly, leads to long-term adverse neurodevelopment, and even mental retardation. Currently, the overall incidence of EUGR in preterm infants is more than 50% in our country, which is higher than that reported abroad. The aim of the present study was to investigate the incidence of intrauterine growth restriction (IUGR) and EUGR in preterm infants in North Anhui Province, and analyze the associated factors of EUGR.Methods:This prospective study was conducted from January 2013 to June 2014 in the NICU of the Firsrt Affiliated Hospital of Bengbu Medical College. Case inclusion criteria were defined as follows:gestational age<37 weeks, admission less than 24 hours after birth, and the length of hospital stay> or=10 days. Those with inherited metabolic diseases, severe congenital malformations, discharge with unstable vital signs, and death during hospitalization were excluded from the present study. All subjects were from North Anhui Province. The premature neonates were managed with an aggressive nutritional approach proposed abroad, and weight, length, and head circumference during the hospital stay, birth history, pathologic pregnancy, complications and associated treatments were collected for each case. Postmenstrual age was calculated using the gestational age at birth and the length of hospital stay, defined as gestational age plus (length of hospital stay/7). The revised Fenton preterm growth charts (2013 Edition), for boys and for girls, respectively, were used as the evaluation criteria of IUGR and EUGR. Descriptive statistical methods were used to analyze the incidence of IUGR and EUGR in preterm infants, and univariate analysis and unconditional multivariate logistic regression model were used to analyze the associated factors of EUGR.Results:A total of 370 preterm infants meeting inclusion criteria were enrolled. There were 241 boys and 129 girls. The median age at admission was 0.5 hours (range 0.17-12 hours). The mean birth gestational age was 34.00±1.94 weeks (range 28+2-36+6 weeks), and the mean birth weight was 2100.91±460.61 g (range 2985-3680 g). Of the 370 preterm infants, data on length and head circumference were available on 272 cases. The mean birth length and head circumference was 44.35±2.76 cm (range 34.00-50.00 cm), and 31.11±1.87 cm (range 25.00-36.00 cm), respectively. The overall incidence of IUGR at birth, assessed by weight, length, and head circumference, was 14.32%,8.09%,8.46%, respectively, and severe IUGR was 4.05%,1.10%,3.31%, respectively. The overall incidence of EUGR at discharge, assessed by weight, length, and head circumference, was 30.81%,18.01%,10.66%, respectively, and severe EUGR was 16.22%,5.88%,4.04%, respectively. The incidences of IUGR, severe IURG, EUGR, and severe EUGR evaluated by weight were the highest overall in the prematurely born infants, by the comparison of the growth parameters such as weight, length, and head circumference. The incidences of IUGR, severe IUGR, and EUGR, measured by weight, were significantly higher in preterm infants with gestational age> or=34 weeks than in those with gestational age <34 weeks (all P<0.05). The incidences of IUGR, severe IUGR, EUGR and severe EUGR were significantly higher in<2000 g group than in> or=2000 g group (all P<0.05), except no statistically significant difference was found in the incidence of severe IUGR, measured by length, between<2000 g group and> or=2000 g group (P>0.05). The incidence of EUGR in male preterm infants, assessed by weight, length, and head circumference at discharge, was 30.29%,19.64%, and 11.90%, respectively, and 15.35%,7.74%,5.36% for severe EUGR, respectively. The incidence of EUGR in female preterm infants, assessed by weight, length and head circumference at discharge, was 31.78%,15.38%,8.65%, respectively, and 17.83%,2.88% and 1.92% for severe EUGR, respectively. No significant differences however were observed in the incidences of EUGR and severe EUGR between the boys and girls (all P>0.05). When compared with the overall incidences of EUGR and severe EUGR, there were also no statistically significant differences (all P>0.05). Grouped by IUGR and non-IUGR, the incidences of EUGR and severe EUGR at discharge, measured by weight, length, and head circumference, were remarkably higher in IUGR group than in non-IUGR group (all P=0.000). The results of unconditional stepwise logistic regression analysis were as follows:1) Assessed by weight at dischagre, birth weight less than 2000 g (OR=3.881), cesarean section (OR=2.898), IUGR judged by birth weight (OR=114.097), stress ulcer (OR=4.163), and hypertensive disorders of pregnancy (OR=3.067) were the independent risk factors for EUGR of male preterm infants, while treatment with amino acid and or lipid emulsion was a protective factor. For female preterm infants, risk factors independently associated with EUGR were large gestational age (OR=2.679), birth weight<2000 g (OR=34.658), length of hospital stay (OR=1.083), and IUGR judged by birth weight (OR=20.201).2) Assessed by length at dischagre, independent risk factors associated with EUGR for male preterm infants were days to reaching to the lowest weight (OR=1.223), IUGR assessed by birth weight (OR=7.109), and IUGR assessed by birth lengh (OR=22.009), while for female preterm infants were birth weight<2000 g (OR=5.289), intrauterine distress (OR=9.616), and IUGR assessed by birth weight (OR=18.946).3) When evaluating with head circumference at dischagre, IUGR assessed by birth weight (OR=6.918) and IUGR assessed by birth head circumference (OR=137.271) were the independent risk factors for EUGR of male preterm infants, while total calories intake not achieving> or=120 kcal/(kg·d) during the hospital course (OR=60.750) and IUGR assessed by birth weight (OR=13.5) were the independent risk factors for EUGR of female preterm infants.Conclusions and study implications:In North Anhui Province, the overall incidence of EUGR, assessed by weight, length, and head circumference at discharge, was 30.81%,18.01%,10.66%, respectively, and severe EUGR was 16.22%,5.88%, 4.04%, respectively, which is slightly higher than that reported abroad, but significantly lower than that reported at home. Weight-growth restriction is predominant for both the preterm infants with IUGR at birth and those with EUGR at discharge. The incidences of EUGR and severe EUGR in male and female preterm infants are similar, closing to the overall incidences. The incidence of EUGR, assessed by weight, length, and head circumference at discharge, is highest in small for gestational age preterm infants (IUGR infants assessed by birth weight). Several factors influence the incidences of EUGR in male and female preterm infants, among which IUGR assessed by birth weight is a common independent risk factor for EUGR, assessed by weight, length, and head circumference at discharge, in both male and female preterm infants, with the greatest impact on both growth restriction for weight in male preterm infants and for length in femal preterm infants.Strengthening prenatal care, reducing cesarean section rate, and managing the pregnancy complications appropriately, such as hypertensive disorders of pregnancy and intrauterine distress, are expected to reduce the birthrate of small for gestational age preterm infants, and thereby decreasing the incidence of EUGR at discharge. Aggressive nutritional approach, using amino acid and or lipid emulsion, if necessary, is expected to reduce the incidence of EUGR in preterm infants. |
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