PURPOSE: To determine the secular trend of the multiple birth rate in Korea from 1981 to 2017. METHODS: This study used birth certificate data covering the years 1981–2017 (20,948,901 births), provided by Statistics Korea. The impact of assisted reproductive technologies (ART) on multiple birth was analyzed by examining data prior to and after the introduction of ART and the national support program for infertile couples in South Korea. The odds ratio (OR) and 95% confidence intervals were calculated to describe the secular trend in the multiple birth rate per 100 births. RESULTS: During this period, the multiple birth rate per 100 births increased by 277 percent from 1.031 to 3.891, the twin birth rate increased from 1.013 to 3.807 (275%), and the triplet birth rate increased from 0.018 to 0.084 (363%). The secular trend of the multiple birth rate remained in the 1.000 level during 1981–1991, but has been rising steadily since 1992. The average increment of the multiple birth rate was 3.9% annually from 1981 through 2017 (peaking at more than 10 percent during 2006–2007). Prior to the introduction of ART in Korea (1981–1984), the multiple birth rate was 1.007, but after its introduction, the multiple birth rate was 1.005 in 1985–1989 (OR, 0.998; 95% confidence interval, 0.982–1.014), 1.084 in 1990–1994 (1.007; 1.060–1.094), 1.891 in 2000–2004 (1.894; 1.866–1.922), 3.127 in 2010–2014 (3.173; 3.129–3.217), and 3.811 in 2015–2017 (3.893; 3.835–3.952). CONCLUSION: Over the past three decades, multiple births have risen dramatically in Korea, primarily due to the increasingly widespread use of fertility therapies, and the delayed age of childbearing. There is a need for more research to understand the factors contributing to multiple births, and the national birth registration systems ought to be reformed to monitor whether multiple births originated spontaneously or from assisted-conception.
Birth Certificates ; Birth Rate ; Family Characteristics ; Fertility ; Humans ; Korea ; Multiple Birth Offspring ; Odds Ratio ; Parturition ; Reproductive Techniques, Assisted ; Triplets ; Twins

Age estimation is important in the practice of forensic science to establish the identity of human remains, as well as with living persons. Particularly in Korea, age estimation in adults has been increase in the demand for incorrect birth records in order to be entitled to civil liability, social benefits, employment. The reduction of pulp cavity size as a result of secondary dentin deposit with increasing age could be used to estimate age. This regressive change can be analyzed using radiological techniques; thus, a variety of methods for dental age estimation based on this approach have been proposed. The purpose of this study is to evaluate the concurrence between the Drusini's method and the Jeon's method using the mandibular first molar on orthopantomographs (OPGs) in Korean adults. A total of 232 OPGs (91 females and 141 males) of Korean individuals with ages ranging from 20 to 69 years were analyzed using Drusini's method and Jeon's method. Our results revealed that the correlation of the two methods with age was statistically significant (r=0.501). Both Drusini's method and Jeon's method showed significant correlation with chronological age, and Jeon's method showed a greater correlation with chronological age (r=0.738) than Drusini's method (r=0.586). The mean absolute error was 7.99 years for Jeon's method and 9.79 years for Drusini's method. Our results demonstrate that Jeon's method using the mandibular first molar on OPGs is a practical and suitable method for age estimation in Korean adults.
Adult* ; Age Determination by Teeth ; Birth Certificates ; Dentin ; Dentin, Secondary ; Employment ; Female ; Forensic Sciences ; Humans ; Korea ; Methods* ; Molar* ; Radiography

PURPOSE: To compare the relationship between intertwin birth weight discordance and maternal age at birth. METHODS: There were 51,726 pairs of twins born from 2007 to 2014 according to the birth certificate data of Korea Statistics (3,701,806 births). The data were excluded due to extra marital births, home births, and teenage births. Birth weight discordance rate (%) was calculated according to the following formula: (larger birth weight - smaller birth weight)/(birth weight of the larger twin) ×100. The odds ratio of intertwin birth weight discordance rate (≥25%) in maternal age at birth was calculated by logistic regression adjusted by the year of birth, gestational age, maternal education, infantile gender and paternal age. RESULTS: The mean birth weight of the heavier twin and that of the lighter twin were 2.536 kg and 2.254 kg, respectively. The mean birth weight difference of intertwins was 0.282 kg. The mean birth weight discordance rate by maternal age was 10.5 percent for maternal ages between 20 and 29 years, 11.0 percent for between 30 and 34 years, and 11.4 percent for 35 years and older. The frequency of birth weight discordance level of ≥25 percent increased as the maternal age increased. The rate of birth weight discordance (≥25%) was 7.7 percent for maternal ages between 20 and 29 years, 8.3 percent for between 30 and 34 years, and 8.7 percent in for 35 years and older. Compared with women from 20 to 29 years of age, the odds ratio of ≥25 percent discordance was 1.094 (95% confidence interval: 1.005~1.190) for 30 to 34 years, and 1.164 (1.401~1.301) for 35 years and older. The odds ratio of ≥25 percent discordance for the different-sexed twins was higher than that of the same-sexed twins in overall maternal age groups of 20 to 29 years, 30 to 34 years, and 35 years and older. CONCLUSION: The risk of birth weight discordance level of ≥25 percent was associated with the older maternal age. More research is required to understand the risk factors of intertwin birth weight discordance for older women.
Birth Certificates ; Birth Weight* ; Education ; Female ; Gestational Age ; Humans ; Korea* ; Logistic Models ; Maternal Age* ; Odds Ratio ; Parturition* ; Paternal Age ; Risk Factors ; Twins

PURPOSE: Spontaneous neonatal gastric perforation is a rare but fatal disease with unclear etiology. In this study, we reviewed its clinical manifestations, outcomes, and discussed the etiology and prognostic factors. METHODS: There were 12 neonates with gastric perforation in our hospital from 1989 to 2015. Their medical records were reviewed retrospectively including birth record, associated disease, site and size of perforation, type of surgical management, clinical outcome. Also, the prognostic factors were analyzed. RESULTS: The median gestational age and birth weight was 32 weeks (range, 26-43 weeks; preterm birth rate, 66.7%) and 1,883 g (range, 470-4,400 g), respectively. Five patients had associated gastrointestinal anomalies including esophageal atresia and tracheoesophageal fistula (two patients), midgut volvulus, non-rotation and microcolon, and meconium plug syndrome. The median age at surgery was six days after birth (range, 2-13 days), and the median weight at surgery was 1,620 g (range, 510-3,240 g). Upper third part of stomach was the most frequently involved location of perforation. The size of perforation varied from pin point to involving the whole greater curvature. Primary repairs were done in seven cases, and in five cases, resections of necrotic portion were needed. Mortality rate was 33.3% (n=4), morbidity (re-operation) rate was 16.7% (n=2). The causes of death were sepsis (n=3), and heart failure from Ebstein anomaly (n=1). The median hospital stay was 92.5 days (range, 1-176 days). The factors mentioned as prognostic factors in previous studies showed no significant relations to the mortality and morbidity in our study. CONCLUSION: There were improvements of outcomes in patients with large size perforation. As previous studies, we assume these improvements were possible due to the improvements of critical care medicine. Given that rare incidence, a multi-center study can help us get a better understanding of this disease, and a better outcome.
Birth Certificates ; Birth Weight ; Cause of Death ; Critical Care ; Ebstein Anomaly ; Esophageal Atresia ; Gestational Age ; Heart Failure ; Humans ; Incidence ; Infant, Newborn ; Intestinal Volvulus ; Length of Stay ; Meconium ; Medical Records ; Mortality ; Parturition ; Premature Birth ; Retrospective Studies ; Sepsis ; Stomach ; Tracheoesophageal Fistula

PURPOSE: The primary objective of this study is to identify the changes in the birth weight of full term newborns in the Korean population over the past 5 years and to delineate their relating factors. METHODS: We used the dynamic statistics of the population from the Korea National Statistical Office which represents the current trend of social stratification. We analyzed birth records over a five-year period & studied the changes in the birth weight of full term newborns by year, gender, gestational age & Seoul or non-Seoul areas from 2002 to 2006. RESULTS: The mean birth weights of newborns in the 37~40 weeks range were 3,312 g and 3,210 g for male & female infants, respectively & decreased by 62 g and 49 g over the past five years. The birth weight in full term newborns decreased from 3,299 g to 3,243 g in total and there was no difference in the changes of birth weigh for each year, both sexes, each gestational age & capital or non-capital areas. CONCLUSION: The birth weight of full term newborns in Korea has decreased over the past five years, showing that there are no big differences between genders, gestational ages, and Seoul or non-Seoul areas. We need to study more prospectively the demographic variables which cause the trend if the mean birth weight continues to decrease.
Birth Certificates ; Birth Weight ; Female ; Gestational Age ; Humans ; Infant ; Infant, Newborn ; Korea ; Male ; Parturition

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.
Aged ; Birth Certificates ; Birth Rate ; Female ; Humans ; Infant ; Infant Mortality ; Infant, Low Birth Weight ; Infant, Newborn ; Infant, Premature ; Infant, Very Low Birth Weight ; Korea ; Maternal Age ; Mothers ; Parturition ; Population Characteristics ; Social Conditions ; Social Environment ; Social Problems ; Survival Rate

PURPOSE: The aim of this study was to investigate the risk of low birth weight associated with delayed first childbearing in Korea. METHODS: The national birth certificate data of the singletons and first babies in Korea from January 2001 to December 2003 (n=736,167) was used. Outcome measures were rates of low birth weight infant, very low birth weight infant between 6 maternal age group (<20 years, 20-24 years, 25-29 years, 30-34 years and >>5years). Odd ratios were calculated by multiple logistic regression on marital state, maternal education, maternal occupation, paternal occupation, duration of marriage and address. RESULTS: Compared with women aged 25 to 29 years, women aged 30-35 years, 35-40 years and over 40 years had higher odds ratios of low birth weight, odd ratios were 1.3, 2.1, 2.4 respectively. Even though adjusted by marital state, maternal education, maternal occupation, paternal occupation, duration of marriage and address, odds ratios were 1.3, 1.9, 2.0 respectively. Compared with women aged 25 to 29 years, women aged 30-35 years, 35-40 years and over 40 years had higher odds ratios of very low birth weight, odd ratios were 1.8, 3.3, 3.7 respectively. Even though adjusted, odd ratios were 1.6, 2.7, 2.6 respectively. Compared with the incidence of low birth weight in each maternal age, maternal education, marital state, married, high school graduated thirties women was lower incidence than unmarried, high school graduated twenties women. CONCLUSION: These findings suggest that delayed childbearing increase the risk of low birth weight and very low birth weight, but if pregnant women have better socioeconomic condition, the impact of advanced maternal age on the risk of low birth weight will be decreased.
Birth Certificates ; Education ; Female ; Humans ; Incidence ; Infant, Low Birth Weight* ; Infant, Newborn ; Infant, Very Low Birth Weight ; Korea ; Logistic Models ; Marriage ; Maternal Age ; Occupations ; Odds Ratio ; Outcome Assessment (Health Care) ; Pregnant Women ; Reproductive Behavior ; Single Person

PURPOSE: A universal standard of the birth weight for gestational age cannot be made since birth weight distribution varies with races, nations and eras. This report aims to establish the birth weight for gestational age patterns by sex, plurality, and parity, specific for Korean live births. METHODS: The national birth certificate data of all live births in Korea from January 2000 to December 2004 were used: for live births with gestational age 24 weeks to 42 weeks (n=2,585,5160), mean birth weight, standard deviation and 10th, 25th, 75th and 90th percentile values were obtained for each gestational age group by one week increment. To establish final standard values of Korean birth weight distribution by gestational age, the finite mixture model to eliminated erroneous birth weights was used for respective gestational age. Same as above method the birth weight for gestational age standard by sex, plurality, and parity were completed . RESULTS: The male newborns are more heavier than female during the entire gestational age. The singletons are more heavier than twin during the entire gestational age. The para 2 are more heavier than the para 1 during the entire gestational age. Korean standard was more heavier in 10th and 50th percentile than Lubchenco's standard. Alexander's standard was more heavier in 50th and 90th percentile than Korean standard. CONCLUSION: These birth weight for gestational age patterns by sex, plurality, and parity are similar to the other standards. I hope that for Korean infants, this curve will help clinicians in defining and managing the large for gestational age infants and also for infants with intrauterine growth retardation.
Asian Continental Ancestry Group ; Birth Certificates ; Birth Weight* ; Continental Population Groups ; Female ; Fetal Growth Retardation ; Gestational Age* ; Hope ; Humans ; Infant ; Infant, Newborn ; Korea ; Live Birth ; Male ; Parity* ; Parturition* ; Twins

OBJECTIVE: To evaluate the pregnancy outcomes of women with congenital uterine anomaly exceeding 20 weeks of gestation. METHODS: We reviewed retrospectively the birth records of the Seoul National University Hospital between January 1, 1990, and December 31, 2005. We grouped congenital uterine anomalies into five classes, namely bicornuate, didelphys, septate, arcuate, and unicornuate uterus. We compared the pregnancy outcomes with each anomaly. RESULTS: We found 106 cases of congenital uterine anomaly within a given period of time. There were 63 cases of bicornuate uterus, 19 cases of didelphys, 16 cases of septate uterus, 5 cases of arcuate uterus, and 3 cases of unicornuate uterus. The overall preterm delivery rate was 22.6% (24/106) and cesarean section rate was 74.5% (79/106). A high cesarean section rate was due to metroplasty, abnormal fetal presentation, and uterine anomaly itself. The preterm delivery rate and cesarean section rate of each uterine anomaly did not differ statistically from one another. Five fetuses were stillborn, and one fetus died after birth because of a placenta abruption. The overall take-home baby rate was 94.3% (100/106). There was no maternal mortality and only one case was suffered from postpartum bleeding. CONCLUSION: Our results suggest that the most of women with uterine anomaly exceeding 20 weeks of gestation may take their baby home.
Birth Certificates ; Cesarean Section ; Female ; Fetus ; Hemorrhage ; Humans ; Labor Presentation ; Maternal Mortality ; Obstetric Labor, Premature ; Parturition ; Placenta ; Postpartum Period ; Pregnancy ; Pregnancy Outcome* ; Pregnancy* ; Retrospective Studies ; Seoul ; Uterus

PURPOSE: 'Programming' describes the process that stimulus at a critical period of development has lifelong effects. The fact that low birth weight links to the risk of elevated blood pressures in adult life is well known. This study aims to examine whether this link is evident in the newborn by investigating the relationship of the intrauterine growth indices and neonatal blood pressure(BP). METHODS: We studied 127 neonates who were born at Ewha Womans' Hospital and their mothers enrolled our cohort study during pregnancy. Data on the mothers and details of the birth records were tracked and collected from medical charts. Neonatal BP was measured within 24 hours after birth. RESULTS: Neonatal SBP was positively correlated to intrauterine growth indices; birth weight(BW)(r= 0.4), head circumference(HC)(r=0.4), and birth height(r=0.3). However, an inverse relationship existed, between HC/BW ratio and neonatal SBP(r=-0.4). After adjusting for the baby's sex, maternal BP, and gestational age, neonatal SBP still associated with intrauterine growth indices. SBP was 7 mmHg higher in the highest BW group(> or =90 percentiles) compared to the lowest group(<10 percentiles). On the other hand, SBP was 17 mmHg lower in the highest HC/BW group(> or =90 percentiles) compared in the lowest group(<10 percentiles). CONCLUSION: This study could not find the evidence that intrauterine growth retardation affect on elevated neonatal BP. It suggests that the initiating events of BP programming may occur during postnatal growth period. To identify the critical starting period that intrauterine growth retardation leads to elevated BP, a study tracking BP changes from birth to childhood is required.
Adult ; Birth Certificates ; Blood Pressure* ; Cohort Studies ; Critical Period (Psychology) ; Fetal Growth Retardation ; Gestational Age ; Hand ; Head ; Humans ; Infant, Low Birth Weight ; Infant, Newborn ; Mothers ; Parturition ; Pregnancy