Regional Differences in Preterm Birth Rates: Based on 2003 Birth Certificate Data / 대한주산의학회잡지

OBJECTIVE: Preterm birth is one of the leading causes of infant death and a major contributor to early childhood morbidity. It has been recognized that numerous factors are responsible for the development of preterm delivery. Among these factors, environmental influences have been demonstrated in many studies. The purpose of this study was to analyze the regional variations of preterm birth rates and to reveal the association between environmental influences and preterm birth. METHODS: Based on the 2003 birth certificate data from National Statistical Office, we analyzed 475,680 singleton births with certain gestational age at delivery of seven metropolitan cities and nine provinces in Korea. Multiple logistic regression analysis was used to examine the relationship between preterm birth and regional differences, adjusting for other risk factors such as maternal age, sex of infants, order of the babies and mother's education. RESULTS: The rate of preterm delivery was 3.8 percent. The highest preterm birth rate was observed in Daegu metropolitan city (4.2%), and the lowest in Jeonbuk province (3.2%). Risk of preterm birth was higher in mothers with younger ( or =30 years) ages, with lower educational levels, and in male infants. There was a significant increase in the risk of preterm birth in Daegu metropolitan city (odds ratio (OR) 1.32, 95% confidence interval (CI), 1.19~1.47), Gangwon province (OR 1.27, 95% CI, 1.13~1.43), Gyeongbuk province (OR 1.26, 95% CI, 1.14~1.40), Jeonnam province (OR 1.22, 95% CI, 1.09~1.37), Busan metropolitan city (OR 1.21, 95% CI, 1.09~1.34), Ulsan metropolitan city (OR 1.19, 95% CI, 1.05~1.36), and Gyeonggi province (OR 1.15, 95% CI, 1.05~1.26) as compared with the incidence of preterm birth in Jeonbuk province. CONCLUSION: Regional variations of preterm birth rate was observed among metropolitan cities and provinces in Korea. Further larger scale studies are necessary to determine more specific factors associated with these differences.

Association between Paternal Age and Preterm Birth Based on Birth Certificate Data / 대한주산의학회잡지

OBJECTIVE: To determine whether paternal age is associated with the risk of preterm birth. METHODS: Data were obtained from the 2003 birth certificates registry of 214,413 singleton infants born to women aged 25~29 years in Korea (Korea National Statistical Office). Odds ratios and 95% confidence intervals were calculated from multivariate logistic regression analyses to investigate the associations between paternal age and preterm delivery. RESULTS: The incidence of preterm birth showed a significant difference among the different paternal age groups (p0.05), 1.08 for age 25~29 years (p or =40 years (p<0.01) groups. CONCLUSION: Paternal age is a risk factor for preterm birth and advanced paternal age increases the risk of preterm birth.

Study on Multiple Birth Based on Birth Certificate Data / 대한산부인과학회잡지

OBJECTIVE: Multiple birth implicates the important health and social problems such as preterm birth, low birth weight, high perinatal mortality, and increased medical cost. This study was performed to investigate the multiple birth rate in Korea using the birth certificate data. METHODS: Retrospective review and analysis of data from Korean birth certificate in 1996. RESULTS: Multiple birth rate was 1.4% of total births(683,043 cases). Mean birth weight was 3.29+/-0.47kg for singleton birth and 2.57+/-0.58kg for multiple birth. Mean gestational age was 39.56+/-1.32 weeks for singleton birth and 37.47+/-2.41 weeks for multiple birth. Rate of low birth weight (< 2.5kg) was 14 times higher for multiple birth compared with that of singleton birth, and rate of preterm birth(< 37 weeks) was 10 times higher. Multiple logistic regression analysis was performed to examine the relationship between multiple birth and selected variables including maternal age, job and birth order. As the odds ratio(OR) was 2.47(95% CI: 2.34 - 2.59, p<0.001) for the second birth, and 5.31(95% CI: 4.99 - 5.65, p<0.001) for the third and over birth compared with the first birth, there was a significant correlation between multiple birth and birth order. CONCLUSIONS: Based on the birth certificate data in 1996, the incidence of twin and higher order multiple birth was 1.7%, and a significant correlation between multiple birth and birth order was revealed. Further studies are necessary to elucidate the etiology and prognosis of multiple birth and the developmental problems from birth to adolescence.