• Neonatal Medicine
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• v.25 no.4
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• pp.161-169
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• 2018

Purpose: We assessed the influence of antenatal corticosteroid (ACS) on the inhospital outcomes of intrauterine growth restriction (IUGR) infants. Methods: A retrospective study was conducted with singletons born at $23^{+0}$ to $33^{+6}weeks$ of gestation at Seoul National University Hospital from 2007 to 2014. We compared clinical outcomes between infants who received ACS 2 to 7 days before birth (complete ACS), at <2 or >7 days (incomplete ACS), and those who did not receive ACS in IUGR and AGA infants. Multivariate logistic regression using Firth's penalized likelihood was performed. Results: 304 neonates with 91 IUGR neonates were eligible. Among AGA neonates, mortality (adjusted odds ratio [aOR], 0.13; 95% confidence interval [CI], 0.02 to 0.78), hypotension within 7 postnatal days (aOR, 0.20; 95% CI, 0.06 to 0.64), and severe bronchopulmonary dysplasia (BPD) or death (aOR, 0.24; 95% CI, 0.07 to 0.77) were lower in complete ACS group after adjusting for pregnancy induced hypertension and uncontrolled preterm labor. Mortality (aOR, 0.18; 95% CI, 0.04 to 0.78), hypotension (aOR, 0.26; 95% CI, 0.09 to 0.70), and severe BPD or death (aOR, 0.33; 95% CI, 0.12 to 0.92) were also lower in the incomplete ACS group. Among IUGR infants, after adjusting for birth weight and 5-minute Apgar score, inhaled nitric oxide use within 14 postnatal days was lower in both complete ACS (aOR, 0.07; 95% CI, 0.01 to 0.67) and incomplete ACS (aOR, 0.04; 95% CI, 0.01 to 0.37) groups. Conclusion: ACS was not effective in reducing morbidities in IUGR preterm infants.

• Pediatric Infection and Vaccine
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• v.28 no.3
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• pp.149-159
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• 2021

Purpose: Antibiotic exposure during pregnancy may affect the fetus and newborn in many ways. This study investigated the impact of prenatal antibiotic exposure duration on neonatal outcomes in very preterm (VP) or very low birth weight (VLBW) infants. Methods: From September 2015 to December 2020, preterm infants with gestational age less than 32 weeks or with a BW less than 1,500 g who were admitted to the neonatal intensive care unit, and their mothers were enrolled. Prenatal antibiotic exposure was defined as antibiotics received by mothers before delivery, and the patients were categorized into the non-antibiotic group, short-duration (SD; ≤7 days) group, or long-duration (LD; >7 days) groups. Results: A total of 93 of 145 infants were exposed to prenatal antibiotics, among which 35 (37.6%) were in the SD group and 58 (62.4%) were in the LD group. Infants in the LD group had a significantly higher birth weight-for-gestational-age (BW/GA) Z-score than those in the non-antibiotic group, even after the adjustment for confounding factors (beta, 0.258; standard error, 0.149; P<0.001). Multivariate logistic regression analysis showed that prolonged prenatal antibiotic exposure was independently associated with death (adjusted odds ratio [aOR], 8.926; 95% confidence interval [CI], 1.482-53.775) and composite outcomes of death, necrotizing enterocolitis (NEC), and late-onset sepsis (LOS) (aOR, 2.375; 95% CI, 1.027-5.492). Conclusions: Prolonged prenatal antibiotic exposure could increase the BW/GA Z-score and the risk of death and composite outcomes of death, NEC, and LOS in VP or VLBW infants.

• Journal of Preventive Medicine and Public Health
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• v.36 no.2
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• pp.117-124
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• 2003

Objectives : This study was performed to examine the relationship between maternal exposure to environmental tobacco smoke (ETS) and pregnancy outcomes (low birth weight or preform baby) in a prospective cohort study. Methods : We made a pregnant women's cohort, and followed the pregnancy outcomes, between May 1st 2001 and August 31st 2002. We surveyed 2,250 women who visited our hospital during their 35th gestational week, with a self-administered questionnaire. The final total of mother-infant pairs analyzed in this study was 1,712. We used a multiple logistic regression analysis to analyze the effect of maternal ETS on the incidence of preform or low birth weight, and a linear regression analysis for the birth weight and gestational age. Results : Higher exposure to ETS (>=1 hours/day) during pregnancy was more negatively associated with the gestational age and birth weight, than no exposure to ETS (no or less than 1 hour). Maternal exposure to ETS was associated with preform baby(adjusted odds ratio (AOR) 1.7; 95% confidence interval (CI) 0.9, 3.3) and low birth weight (AOR 2.3; 95% CI 0.9, 5.5). In addition, we found that maternal ETS may reduce the birth weight by 70g after adjusting for potential confounding factors. Conclusions : This study suggests that maternal exposure to ETS during pregnancy may increase the frequency of low birth weights and preform births.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.23 no.4
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• pp.366-376
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• 2020

Purpose: To assess the association between birth weight and the development of functional gastrointestinal disorders (FGIDs) in the first year of life. Methods: This is a secondary analysis of a prospective cohort multicenter study including neonates, consecutively enrolled at birth, and followed up for one year. At birth all infants were classified by birth weight as extremely low (ELBW), very low, or low when <1,000, <1,500, and <2,500 g, respectively, and by birth weight for gestational age as appropriate (AGA, weight in the 10-90th percentile), small (SGA, weight <10th percentile), and large (LGA, weight >90th percentile) for gestational age. FGIDs were classified according to the Rome III criteria and assessed at 1, 3, 6, and 12 months of life. Results: Among 1,152 newborns enrolled, 934 (81.1%) completed the study: 302 (32.3%) were preterm, 35 (3.7%) were ELBW, 104 (11.1%) were SGA, 782 (83.7%) were AGA, and 48 (5.1%) were LGA infants. Overall, throughout the first year of life, 718 (76.9%) reported at least one FGID. The proportion of infants presenting with at least one FGID was significantly higher in ELBW (97%) compared to LBW (74%) (p=0.01) and in LGA (85.4%) and SGA (85.6%) compared to AGA (75.2%) (p=0.0001). On multivariate analysis, SGA was significantly associated with infantile colic. Conclusion: We observed an increased risk of FGIDs in ELBW, SGA, and LGA neonates. Our results suggest that prenatal factors determining birth weight may influence the development of FGIDs in infants. Understanding the role of all potential risk factors may provide new insights and targeted approaches for FGIDs.

• 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.

• 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.62 no.3
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• pp.102-107
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• 2019

Purpose: This study compared the iron statuses of small for gestational age (SGA) and appropriate for gestational age (AGA) infants at birth. Methods: The clinical data of 904 newborn infants admitted to the neonatal intensive care unit were reviewed. Blood samples were drawn from the infants within 24 hours after birth. Serum ferritin level was used as a marker of total iron status. Results: In this study, 115 SGA (GA, $36.5{\pm}2.9weeks$; birth weight [BW], $1,975{\pm}594.5g$) and 717 AGA (GA, $35.1{\pm}3.5weeks$; BW, $2,420.3{\pm}768.7g$) infants were included. The SGA infants had higher hematocrit levels ($50.6%{\pm}5.8%$ vs. $47.7%{\pm}5.7%$, P<0.05) than the AGA infants. No difference in serum ferritin level (ng/mL) was found between the groups (mean [95% confidence interval]: SGA vs. AGA infants, 139.0 [70.0-237.0] vs. 141.0 [82.5-228.5]). After adjusting for gestational age, the SGA infants had lower ferritin levels (147.1 ng/mL [116.3-178.0 ng/mL] vs. 189.4 ng/mL [178.0-200.8 ng/mL], P<0.05). Total body iron stores were also lower in the SGA infants than in the AGA infants (185.6 [153.4-211.7] vs 202.2 [168.7-241.9], P<0.05). Conclusion: The SGA infants had lower ferritin and total body iron stores than the AGA infants. The SGA infants affected by maternal hypertension who were born at late preterm had an additional risk of inadequate iron store. Iron deficiency should be monitored in these infants during follow-up.

• Clinical and Experimental Pediatrics
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• v.51 no.2
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• pp.145-149
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• 2008

Purpose : To examine whether changes of oxygenation index (OI) by postnatal age were different by the number of surfactant administration, and different between subgroups of survival and death. Methods : From January 2005 to June 2006, preterm infants (n=84) diagnosed as respiratory distress syndrome (RDS) and treated with surfactant and ventilator were included. They were divided into two groups: Group I (n=54) was infants received surfactant, one time and Group II (n=30) was infants received surfactant, two times. We also categorized group I & II infants into two subgroups in each group: survival group and death group. We calculated OI at birth, 24 hr, 48 hr and 72 hr after birth. Results : Gestational age ($30.1{\pm}2.6wk\;vs\;28.4{\pm}3.4wk$) and birth weight ($1,478{\pm}442g\;vs\;1,199{\pm}495g$) were different between group I and group II. In preterm infants with RDS, the changes of OI by postnatal age were different between groups (P=0.001) and different with time change (P<0.001). In group I, the OI of survival subgroup showed decreasing by postnatal age compared with death subgroup, but was not significantly different between subgroups. In group II, the change of OI was not different between survival and death. Conclusion : These findings suggest that OI helps to predict the respiratory condition in preterm infants with RDS.

• Neonatal Medicine
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• v.18 no.2
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• pp.320-327
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• 2011

Purpose: To determine the effect of changing practice guidelines designed to avoid hyperoxia or hypoxia in very low birth weight or very preterm infants. Methods: We analyzed a database of <1,500 g birth weight or <32 weeks of gestation infants who were born and admitted to the neonatal intensive care unit of Chungnam National University Hospital from January 2007 to July 2010. First, we defined the relationship between arterial partial pressure of oxygen ($PaO_2$) and pulse oxygen saturation ($SpO_2$). When we evaluated 96 pairs of $PaO_2$ and $SpO_2$ measurements, oxygen saturation was 90-94% at a $PaO_2$ of 43-79 mmHg on the oxyhemoglobin dissociation curve, according to pulse oximetry. Based on this observation, a change in practice was instituted in August 2008 with the objective of avoiding hypoxia and hyperoxia in preterm infants with targeting a $SpO_2$ 90-94% (period II). Before the change in practice, high alarms for $SpO_2$ were set at 100% and low alarms at 95% (period I). Results: Sixty-eight infants the met enrollment criteria and 38 (56%) were born during period II, after the change in $SpO_2$ targets. Demographic characteristics, except gender, were similar between the infants born in both periods. After correcting for the effect of confounding factors, the rates for mortality, severe retinopathy of prematurity, and IVH attended to be lower than those for infants in period II. No difference in the rate of patent ductus arteriosus needed to treat was observed. Conclusion: A change in the practice guidelines aimed at avoiding low oxygen saturation and hyperoxia did not increase neonatal complication rates and showed promising results, suggesting decreased mortality and improvements in short term morbidity. It is still unclear what range of oxygen saturation is appropriate for very preterm infants but the more careful saturation targeting guideline should be considered to prevent hypoxemic events and hyperoxia.

• Korea journal of population studies
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• v.35 no.1
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• pp.131-149
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• 2012

This study examined the effect of parental socioeconomic position on the association between birth outcomes and infant mortality in early and late 2000's. Linked Birth and Infant Death data sets from 2001 to 2003 (T1) and from 2006 to 2008 (T2), provided by the Korea National Statistical Office, were used for analysis. Birth outcomes were categorized into four groups: normal term, small-for-gestational age (SGA), large-for-gestational age (LGA) and intrauterine growth retardation (IUGR). Infant death was defined as the death of a live-born child under one year of age; indicators of parental socioeconomic position were limited to parental education and occupation. The results showed that T2 infant mortality hazard ratios of SGA and IUGR have increased compared to T1. Particularly, preterm and low birth weight babies with shorter gestational age and lighter birth weight than T1 have elevated in T2, possibly indicating that population quality might be continuously aggravated. Moreover, the effect of maternal age on infant mortality has disappeared, rather that of parents' socioeconomic position has increased during the periods, which entailed growing disparities in infant mortality by their social class. Further studies should be therefore done to estimate the effect of parental socioeconomic position on the relationship between birth outcomes and infant mortality in the near future.