• Journal of Preventive Medicine and Public Health
• /
• v.55 no.4
• /
• pp.371-378
• /
• 2022

Objectives: No studies have examined the association between preterm birth rates and socioeconomic factors in Japan using nationwide statistical data. We analyzed the association between preterm birth rates and household occupation using Vital Statistics data. Methods: Aggregated Vital Statistics data from Japan from 2007 to 2019 were obtained from the Ministry of Health, Labour and Welfare. From the data, the number of births according to year, age group, gestational period, number of pregnancies, and household occupation were used in this study. Crude preterm birth rates and preterm birth rates adjusted by maternal age according to household occupation were calculated for each year. Poisson regression analysis was conducted to evaluate the association between household occupation and preterm births. Results: Unemployed households had the highest preterm birth rate, and households with an occupation classification of "full-time worker 2" (an employee at a large company, civil servant, or board member) had the lowest preterm birth rate throughout each period. Poisson regression analysis revealed that unemployed households were statistically significantly associated with a high preterm birth risk. In contrast, the preterm birth rate adjusted by maternal age remained stable throughout each period regardless of household occupation, and preterm birth rates were found not to have increased in recent years in Japan. Conclusions: Unemployed households had higher preterm birth rates than other household occupations. Further studies investigating the characteristics of unemployed households are needed to identify the reasons for this disparity.

• ETRI Journal
• /
• v.44 no.5
• /
• pp.826-836
• /
• 2022

Signal decomposition is a computational technique that dissects a signal into its constituent components, providing supplementary information. In this study, the capability of two common signal decomposition techniques, including wavelet-based and empirical mode decomposition, on preterm birth classification was investigated. Ten time-domain features were extracted from the constituent components of electrohysterogram (EHG) signals, including EHG subbands and EHG intrinsic mode functions, and employed for preterm birth classification. Preterm birth classification and anticipation are crucial tasks that can help reduce preterm birth complications. The computational results show that the preterm birth classification obtained using wavelet-based decomposition is superior. This, therefore, implies that EHG subbands decomposed through wavelet-based decomposition provide more applicable information for preterm birth classification. Furthermore, an accuracy of 0.9776 and a specificity of 0.9978, the best performance on preterm birth classification among state-of-the-art signal processing techniques, were obtained using the time-domain features of EHG subbands.

• IEIE Transactions on Smart Processing and Computing
• /
• v.4 no.2
• /
• pp.103-109
• /
• 2015

In this paper, a novel method for the classification of term and preterm birth is proposed based on time-frequency analysis of electrohysterogram (EHG) using multivariate empirical mode decomposition (MEMD). EHG is a promising study for preterm birth prediction, because it is low-cost and accurate compared to other preterm birth prediction methods, such as tocodynamometry (TOCO). Previous studies on preterm birth prediction applied prefilterings based on Fourier analysis of an EHG, followed by feature extraction and classification, even though Fourier analysis is suboptimal to biomedical signals, such as EHG, because of its nonlinearity and nonstationarity. Therefore, the proposed method applies prefiltering based on MEMD instead of Fourier-based prefilters before extracting the sample entropy feature and classifying the term and preterm birth groups. For the evaluation, the Physionet term-preterm EHG database was used where the proposed method and Fourier prefiltering-based method were adopted for comparative study. The result showed that the area under curve (AUC) of the receiver operating characteristic (ROC) was increased by 0.0351 when MEMD was used instead of the Fourier-based prefilter.

• Health Policy and Management
• /
• v.25 no.4
• /
• pp.277-284
• /
• 2015

Background: This study investigates the relationship of socioeconomic status with adverse birth outcomes (low birth weight, preterm birth) and the relationship of socioeconomic status with infant mortality, using the birth cohort in Korea, 1995-2010. Methods: 8,648,035 births from National Statistics Offics, 1995-2010 were studied with respect to social variation in adverse birth outcomes and infant mortality in Korea. The effect of social inequality was examined against adverse birth outcomes and infant mortality using multivariate logistic regression after controlling for other covariates. Results: Social inequality were observed in adverse birth outcomes: low birth weight (LBW, 1,500-2,499 g), very LBW (1,000-1,499 g), and extremely LBW (500-999 g) as well as moderately preterm birth (PTB, 33-36 weeks), very PTB (28-32 weeks), extremely PTB (22-27 weeks), and infant mortality. The effect of social inequality was higher among moderately LBW (1,500-2,499 g) and PTB (33-36 weeks) than very or extremely LBW and PTB. Conclusion: The social inequality in adverse birth outcomes (low birth weight and preterm) and infant mortality existed and increased in Korea from 1995 to 2010. The effect of maternal education on adverse birth outcomes as well as infant mortality was apparent in the study results. Especially, social inequailiy in infant mortality was greater among the sub-normal births (low birth weight [1,500-2,499 g] or preterm birth [33-36 weeks]), which suggests, social interventions should aim at more among the subnormal births. This study suggest that tackling inequality in births as well as infant mortality should be focused on the social inequality itself.

• Journal of health informatics and statistics
• /
• v.43 no.4
• /
• pp.255-266
• /
• 2018

Objectives: This study compared the risk of preterm birth and low birth weight between native-born and foreign-born women. Methods: By Using the birth registration data, every woman who gave birth between 2010 and 2016 in Korea was included in the analysis. Duration from marriage to pregnancy was measured by month and multiple socioeconomic and demographic characteristics were controlled. Preterm birth (<37 weeks) and low birth weight (<2.5 kg) were used for outcome variables. Descriptive statistics and logistic regression were used for data analysis with Stata. Results: The risks of preterm birth and low birth weight for native-born and foreign-born women differed according to the duration of marriage or birth order. For the first infant, foreign-born women were more likely to have pereterm birth or low birth weight than the native-born in the early stage of marriage but nativeborn women had higher risks than the foreign-born in the middle and later stage of marriage. For the second infant, foreign-born women were less likely to have pereterm birth or low birth weight than the native-born regardless of the duration of marriage. Conclusions: The results of this study demonstrates that the risk of preterm birth and low birth weight for foreign-born women is concentrated on the early stage of marriage. Institutional and cultural supports should be given to foreign-born women to help their early settlement in the Korean society.

• Clinical and Experimental Pediatrics
• /
• v.49 no.1
• /
• pp.14-17
• /
• 2006

Infants who are born prematurely or with low birth weight should be immunized at the same postnatal chronologic age. They should receive BCG, DTaP, IPV vaccines according to the same recommended schedule as full term infants. Hepatitis B vaccine schedule is modified when hepatitis B vaccine is administered a infant with birth weight less than 2,000 g. The recommended standard dose of each vaccine should be administered. Proportion of children experiencing vaccine-related adverse events dose not differ between full-term and preterm infants. Immunization with routinely recommended childhood vaccines is safe for preterm and low birth weight infants.

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

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.26 no.3
• /
• pp.146-155
• /
• 2023

Purpose: The starting time for probiotic supplementation in preterm infants after birth varies widely. This study aimed to investigate the optimal time for initiating probiotics to reduce adverse outcomes in preterm or very low birth weight (VLBW) infants. Methods: Medical records of preterm infants born at a gestational age (GA) of <32 weeks or VLBW infants in 2011-2020 were reviewed respectively. The infants who received Saccharomyces boulardii probiotics within 7 days of birth were grouped into an early introduction (EI) group, and those who received supplemented probiotics after 7 days of birth were part of the late introduction (LI) group. Clinical characteristics were compared between the two groups and analyzed statistically. Results: A total of 370 infants were included. The mean GA (29.1 weeks vs. 31.2 weeks, p<0.001) and birth weight (1,235.9 g vs. 1491.4 g, p<0.001) were lower in the LI group (n=223) than in the EI group. The multivariate analysis indicated that factors affecting the LI of probiotics were GA at birth (odds ratio [OR], 1.52; p<0.001) and the enteral nutrition start day (OR, 1.47; p<0.001). The late probiotic introduction was associated with a risk of late-onset sepsis (OR, 2.85; p=0.020), delayed full enteral nutrition (OR, 5.44; p<0.001), and extrauterine growth restriction (OR, 1.67; p=0.033) on multivariate analyses after adjusting for GA. Conclusion: Early supplementation of probiotics within a week after birth may reduce adverse outcomes among preterm or VLBW infants.

• The Korean Journal of Health Service Management
• /
• v.8 no.3
• /
• pp.147-155
• /
• 2014

The objective of the study was to analyze the regional variance of late preterm birth (LPT: 34-36 weeks) by analyzing 2008-2012 birth certificated data of seven metropolitan cities (536,984 births: primiparous singleton birth) from Korea Statistics. The odds ratio and 95% confidence intervals were calculated from multinominal logistic regression analyses to describe the regional variance of LPT adjusted for maternal and infantile variables. The highest incidence of LPT rate by region were observed in Ulsan metropolitan city (3.7 percent), and the lowest in Deajon metropolitan city (3.1 percent). After adjustment by logistic regression for infantile sex, maternal variables, there was a significant increase in the risk of late preterm birth in Ulsan metropolitan city (odds ratio: 1.21) as compared with the incidence of LPT in Deajon metropolitan city. The odds ratio of LPT by region were 1.17 in Daegu metropolitan city, 1.13 Busan metropolitan city, and 1.12 in Incheon metropolitan city. More research is required to understand the risk factors for late preterm birth in this area including socio-demographic factors, medical factors, and regional and environmental factors.

• Journal of Preventive Medicine and Public Health
• /
• v.37 no.4
• /
• pp.300-305
• /
• 2004

Objectives : The exposure to particulate air pollution during the pregnancy has reported to result in adverse pregnancy outcome such as low birth weight, preterm birth, still birth, and intrauterine growth retardation (IUGR). We aim to assess whether prenatal exposure of particulate matter less than 10 (m in diameter ($PM_{10}$) is associated with preterm birth in Seoul, South Korea. Methods : We included 382,100 women who delivered a singleton at 25-42 weeks of gestation between 1998 and 2000. We calculated the average PM10 exposures for each trimester period and month of pregnancy, from the first to the ninth months, based on the birth date and gestational age. We used three different models to evaluate the effect of air pollution on preterm birth; the logistic regression model, the generalized additive logistic regression model, and the proportional hazard model. Results : The monthly analysis using logistic regression model suggested that the risks of preterm birth increase with PM10 exposure between the sixth and ninth months of pregnancy and the highest risk was observed in the seventh month (adjusted odds ratio=1.07, 95% CI=1.01-1.14). We also found the similar results using generalized additive model. In the proportional hazard model, the adjusted odds ratio for preterm births due to PM10 exposure of third trimester was 1.04 (95% CI=0.96-1.13) and PM10 exposure between the seventh month and ninth months of pregnancy was associated with the preterm births. Conclusions : We found that there were consistent results when we applied the three different models. These findings suggest that air pollution exposure during the third trimester pregnancy has an adverse effect on preterm birth in South Korea.