• Clinical and Experimental Pediatrics
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• v.51 no.3
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• pp.233-236
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• 2008

In recent years, Korea has experienced a steadily declining birth rate, which is a serious social problem in the country. Although living conditions have improved, the birth rates for low birth weight infants and preterm babies has increased because more and more women choose to give birth later in life and the social environment has changed. The rise in low birth weight infants may increase infant mortality rates and morbidity rates. However, the recent improvements in neonatal care has elevated the survival rate of low birth weight infants up to 90 percent and lowered the weight of the very low birth weight infants that can now be saved. In this study, we used dynamic population statistics from the Korea National Statistical Office, which represents the current trend of social stratification and the population of this period. We analyzed birth records for a seven-year period and studied the changes in the delivery rate of preterm and low birth weight infants and the problems related to those changes. The results show that the rate of low birth weight infants has increased from 3.79% to 4.35% for the past seven years. The rate of preterm babies rose from 3.79% to 4.89%. The number of babies born from mothers aged 35 or more went up from 6.69% to 11.83% of the total number of the babies born. As maternal age has risen, the risks of delivering a preterm or low birth weight infant have also increased.

• Journal of Yeungnam Medical Science
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• v.4 no.2
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• pp.97-103
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• 1987

Neonatal and obstetrical problems related to the low birth weight infants were evaluated by a retrospective review of the medical records of the 186 low birth weight infants born at Yeungnam-University Hospital during 3 years and 8 months from May 1, 1983 to February 28, 1987. The results were as follows ; 1. The incidence of the low birth weight infants was 4.98% among 3803 live births. 2. Male to female ratio was 1.02:1. 3. The incidence of the low birth weight infants was lowest in mothers of 25 to 29 years, increased in mothers of 19 years of less and 30 to 39 years significantly. 4. There was no difference in the incidence of low birth weight infants between primiparous and multiparous mothers. 5. Common obstetrical complications associated with low weight infants were multiple pregnancy, toxemia and premature rupture of membrane in order of frequency. 6. Common neonatal problems in low birth weight infants were jaundice, idiopathic respiratory, distress syndrome, asphyxia and metabolic dfrangement such as hypocalcemia and hypoglycemia in order of frequency.

• Neonatal Medicine
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• v.25 no.3
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• pp.118-125
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• 2018

Purpose: The pre-pregnancy body mass index (BMI) is associated with adverse neonatal outcomes. However, studies on very low birth weight (VLBW) infants are rare. This study aimed to investigate the effect of maternal pre-pregnancy BMI on VLBW infants. Methods: This retrospective study evaluated singleton VLBW infants born at the CHA Gangnam Medical Center from 2006 to 2016. The neonates were classified into three groups according to the maternal pre-pregnancy BMI: underweight (<$18.5kg/m^2$), normal weight (${\geq}18.5$ to <$23kg/m^2$), and overweight or obese (${\geq}23kg/m^2$). Clinical characteristics and morbidities of mothers and infants were analyzed. Results: A total of 181 infants belonging to underweight (16.6%), normal weight (58.6%), and overweight or obese (24.8%) groups were enrolled. The pre-pregnancy BMI had a significant negative correlation with gestational age (r=-0.198, P=0.001) and a significant positive correlation with the z-score of the birth weight (r=0.078, P=0.001) and body length (r=0.067, P=0.008). The number of extremely preterm infants was significantly higher in the overweight or obese group. The proportion of risk of small for gestational age infants was higher in the underweight group (adjusted odds ratio [OR], 2.958; 95% confidence interval [CI], 1.113 to 7.864), whereas that of infants with severe retinopathy of prematurity was higher in the overweight or obese group (adjusted OR, 9.546; 95% CI, 1.230 to 74.109). Conclusion: In our population of VLBW infants, the pre-pregnancy BMI was associated with gestational age, intrauterine growth, and adverse neonatal outcomes. Therefore, proper weight control before pregnancy is important.

• Journal of Nutrition and Health
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• v.32 no.8
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• pp.877-886
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• 1999

To assess the effect of an antenatal nutritional status on pregnancy outcome, especially neonatal birty weight, one-day 24hr-recall and two-day recording methods for dietary survey and interview for general and obstetric characteristics of each subject were completed and pregnancy outcome was recorded by phone after delivery. 147 pregnant women attending routinely public health centers in Ulsan were divided into 1st trimester(n=36), 2nd trimester(n=102), 3rd trimester(n=71) by LMP(Last Menstrual Period) because some subjects attended repeatedly in different trimester. The subjects were aged 27.9$\pm$2.9 as mean and the level of education was senior high school and more. 20.4% of subjects experienced spontaneous abortion and 30.0% experienced induced abortion in previous pregnancy. Mean intakes of all nutrients except ascorbic acid were significantly different but dietary composition of energy intakes was not different between trimester. Mineral of calcium, iron and zinc did not meet the RDA for pregnancy outcome was about 20%, which consists of spontaneous abortion (3.4%), caesarian section(15.6%), premature delivery(0.7%) and still births(0.7%). The mean birth weight of neonates is 3.31kg the rate of neonatal birth weight below 10th percentile was 8.4% and the rate of low birth weight(<2.5kg) was 3.1%. By analysis of nutrient factors that influence on the neonatal birth weight (NBW), iron intake correlated negatively and zinc intake correlated positively with NBW in 1st trimester but fat and iron intakes correlated with NBW positively in 3rd trimester. Prepregnancy weight, gestational age at delivery and No. of induced abortion had a positive effects on NBW and No. of spontaneous abortion and te severity of morning sickness had a negative effects on NBW.

• Clinical and Experimental Pediatrics
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• v.64 no.7
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• pp.313-321
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• 2021

Here we describe the neurodevelopmental outcomes of very low birth weight (VLBW) infants (birth weight ≤1,500 g) at 3 years of age in the Neonatal Research Network of Japan (NRNJ) database in the past decade and review the methodological issues identified in follow-up studies. The follow-up protocol for children at 3 years of chronological age in the NRNJ consists of physical and comprehensive neurodevelopmental assessments in each participating center. Neurodevelopmental impairment (NDI)-moderate to severe neurological disability-is defined as cerebral palsy (CP) with a Gross Motor Function Classification System score ≥2, visual impairment such as uni- or bilateral blindness, hearing impairment requiring hearing amplification, or cognitive impairment with a developmental quotient (DQ) of Kyoto Scale of Psychological Development score <70 or judgment as delayed by pediatricians. We used death or NDI as an unfavorable outcome in all study subjects and NDI in survivors using number of assessed infants as the denominator. Follow-up data were collected from 49% of survivors in the database. Infants with follow-up data had lower birth weights and were of younger gestational age than those without follow-up data. Mortality rates of 40,728 VLBW infants born between 2003 and 2012 were 8.2% before discharge and 0.7% after discharge. The impairment rates in the assessed infants were 7.1% for CP, 1.8% for blindness, 0.9% for hearing impairment, 15.9% for a DQ <70, and 19.1% for NDI. The mortality or NDI rate in all study subjects, including infants without follow-up data, was 17.4%, while that in the subjects with outcome data was 32.5%. The NRNJ follow-up study results suggested that children born with a VLBW remained at high risk of NDI in early childhood. It is important to establish a network follow-up protocol and complete assessments with fewer dropouts to enable clarification of the outcomes of registered infants.

• Clinical and Experimental Pediatrics
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• v.62 no.10
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• pp.386-394
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• 2019

Background: Preterm infants have difficulty maintaining body temperature after birth. However, clinical guidelines advocate that neonatal body temperature should be maintained at 36.5℃-37.5℃. Purpose: We aimed to investigate the incidence of admission hypothermia in very low birth weight (VLBW) infants and to determine the association of admission temperature with in-hospital mortality and morbidities. Methods: A cohort study using prospectively collected data involving 70 neonatal intensive care units (NICUs) that participate in the Korean Neonatal Network. From registered infants born between January 2013 and December 2015, 5,343 VLBW infants born at less than 33 weeks of gestation were reviewed. Results: The mean admission temperature was 36.1℃±0.6℃, with a range of 31.9℃ to 38.4℃. Approximately 74.1% of infants had an admission hypothermia of <36.5℃. Lower birth weight, intubation in the delivery room and Apgar score <7 at 5 minutes were significantly related to admission hypothermia. The mortality was the lowest at 36.5℃-37.5℃ and adjusted odd ratios for all deaths increased to 1.38 (95% confidence interval [CI], 1.04-1.83), 1.44 (95% CI, 1.05-1.97) and 1.86 (95% CI, 1.22-2.82) for infants with admission temperatures of 36.0℃-36.4℃, 35.0℃-35.9℃, and <35.0℃, respectively. Admission hypothermia was also associated with high likelihoods of bronchopulmonary dysplasia, pulmonary hypertension, proven sepsis, pulmonary hemorrhage, air-leak, seizure, grade 3 or higher intraventricular hemorrhage and advanced retinopathy of prematurity requiring laser therapy. Conclusion: A large portion of preterm infants in Korea had hypothermia at NICU admission, which was associated with high mortality and several important morbidities. More aggressive interventions aimed at reducing hypothermia are required in this high-risk population.

• Clinical and Experimental Pediatrics
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• v.63 no.8
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• pp.284-290
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• 2020

Korea currently has the world's lowest birth rate but a rapidly inreasing number of preterm infants. The Korean Neonatal Network (KNN), launched by the Korean Society of Neonatology under the support of Korea Centers for Disease Control, has collected population-based data for very low birth weight infants (VLBWIs) born in Korea since 2013. In terms of the short-term outcomes of VLBWIs born from 2013 to 2016 registered in the KNN, the survival rate of all VLBWIs was 86%. Respiratory distress syndrome and bronchopulmonary dysplasia were observed in 78% and 30% of all VLBWIs, respectively. Necrotizing enterocolitis occurred in 7%, while 8% of the VLBWIs needed therapy for retinopathy of prematurity in the neonatal intensive care unit (NICU). Sepsis occurred in 21% during their NICU stay. Intraventricular hemorrhage (grade ≥III) was diagnosed in 10%. In terms of the long-term outcomes for VLBWIs born from 2013 to 2014 registered in the KNN, the post-discharge mortality rate was approximately 1.2%-1.5%, mainly owing to their underlying illness. Nearly half of the VLBWIs were readmitted to the hospital at least once in their first 1-2 years of life, mostly as a result of respiratory diseases. The overall prevalence of cerebral palsy was 6.2%-6.6% in Korea. Bilateral blindness was reported in 0.2%-0.3% of VLBWIs, while bilateral hearing loss was found in 0.8%-1.9%. Since its establishment, the KNN has published annual reports and papers that facilitate the improvement of VLBWI outcome and the formulation of essential healthcare policies in Korea.

• Clinical and Experimental Pediatrics
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• v.60 no.1
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• pp.10-16
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• 2017

Purpose: Although procalcitonin (PCT) level is useful for the diagnosis of neonatal sepsis, PCT reliability is inconsistent because of the varied conditions encountered in neonatal intensive care units. This study aimed to investigate PCT levels and factors influencing increased PCT levelin newborns without bacterial infection during the first week of life. Methods: In newborns hospitalized between March 2013 and October 2015, PCT levels were measured on the first, third, and seventh days after birth. Newborns with proven bacterial (blood culture positive for bacteria) or suspicious infection (presence of C-reactive protein expression or leukocytosis/leukopenia) were excluded. Various neonatal conditions were analyzed to identify the factors influencing increased PCT level. Results: Among 292 newborns with a gestational age of $35.2{\pm}3.0$ weeks and a birth weight of $2,428{\pm}643g$, preterm newborns (n=212) had higher PCT levels than term newborns (n=80). Of the newborns, 7.9% had increased PCT level (23 of 292) on the firstday; 28.3% (81 of 286), on the third day; and 3.3% (7 of 121), on the seventh day after birth. The increased PCT level was significantly associated with prenatal disuse of antibiotics (P=0.004) and surfactant administration (P<0.001) on the first day after birth, postnatal use of antibiotics (P=0.001) and ventilator application (P=0.001) on the third day after birth, and very low birth weight (P=0.042) on the seventh day after birth. Conclusion: In newborns without bacterial infection, increased PCT level was significantly associated with lower gestational age and respiratory difficulty during the first week of life. Further studies are needed for clinical applications.

• Neonatal Medicine
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• v.16 no.1
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• pp.36-46
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• 2009

Purpose: To evaluate the neonatal statistics on a national basis, data for birth characteristics and neonatal mortality were collected and analyzed from 57 hospitals in Korea. Methods: Questionnaires were distributed to determine the characteristics of neonatal births and mortality rates in 57 hospitals in Korea during 2007. We analyzed the characteristics of all inborn births and hospitalized neonates in the neonatal care units (NICUs) and compared the results with published Korean data from 1996 and 2002. Results: A total of 40,433 inborn live births were reported from the 57 hospitals during 2007. Pre-term, term, and post-term births comprised 24.2%, 75.6%, and 0.2% of the neonates, respectively. Low birth weight infants (LBWIs), very low birth weight infants (VLBWIs), and extremely low birth weight infants (ELBWIs) made up 22.0%, 4.6%, and 1.7% of the neonates, respectively. A total of 21,957 (collected by gestational period) and 21,356 (collected by birth weight) neonates were hospitalized in the 57 NICUs. Pre-term, term, and post-term neonates comprised 39.8%, 59.8%, and 0.4% of the neonates, respectively. LBWIs, VLBWIs, and ELBWIs made up 37.3%, 9.5%, and 3.3% of the neonates, respectively. Pre-term, term, and post-term neonates had mortality rates of 4.5%, 0.7%, and 3.7%, respectively, while the mortality rates of LBWIs, VLBWIs, and ELBWIs were 4.7%, 15.3%, and 32.2%, respectively. In comparison with prematurity data from 1996 and 2002, LBWIs, and ELBWIs had a marked increase in birth frequency and a decreased mortality rate in Korea during 2007. Conclusion: The number of live births and the survival rate of pre-term neonates, especially VLBWIs and ELBWIs, are increasing. Even though the outcomes of neonatal care are improving, further efforts to manage these premature infants are needed.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.18 no.2
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• pp.100-107
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• 2015

Purpose: We investigated the iron status of very low birth weight infants receiving multiple erythrocyte transfusions during hospitalization in the neonatal intensive care unit (NICU). Methods: We enrolled 46 very low birth weight infants who were admitted to the Kyungpook National University Hospital between January 2012 and December 2013. Serum ferritin was measured on their first day of life and weekly thereafter. We collected individual data of the frequency and volume of erythrocyte transfusion and the amount of iron intake. Results: A total of 38 (82.6%) of very low birth weight infants received a mean volume of $99.3{\pm}93.5mL$ of erythrocyte transfusions in NICU. The minimum and maximum serum ferritin levels during hospitalization were $146.2{\pm}114.9ng/mL$ and $456.7{\pm}361.9ng/mL$, respectively. The total volume of erythrocyte transfusion was not correlated to maximum serum ferritin concentrations after controlling for the amount of iron intake (r=0.012, p=0.945). Non-transfused infants took significantly higher iron intake compared to infants receiving ${\geq}100mL/kg$ erythrocyte transfusion (p<0.001). Minimum and maximum serum ferritin levels of non-transfused infants were higher than those of infants receiving <100 mL/kg erythrocyte transfusions (p=0.026 and p=0.022, respectively). Infants with morbidity including bronchopulmonary dysplasia or retinopathy of prematurity received a significantly higher volume of erythrocyte transfusions compared to infants without morbidity (p<0.001). Conclusion: Very low birth weight infants undergoing multiply erythrocyte transfusions had excessive iron stores and non-transfused infants also might had a risk of iron overload during hospitalization in the NICU.