Background: Maladaptation to vascular, metabolic, and physiological changes during pregnancy can lead to fetal growth disorders. Moreover, adverse outcomes during pregnancy can further increase the risk of cardiovascular and metabolic diseases in mothers. Delivering a large-for-gestational-age (LGA) baby may indicate a pre-existing metabolic dysfunction, whereas delivering a small-for-gestational-age (SGA) baby may indicate a pre-existing vascular dysfunction. This study aims to assess the risk of hypertension (HTN) and diabetes mellitus (DM) in women with normal body mass index (BMI) scores who did not experience gestational DM or hypertensive disorders during pregnancy based on the offspring’s birthweight. Methods: This retrospective nationwide study included women with normal BMI scores who delivered a singleton baby after 37 weeks. Women with a history of DM or HTN before pregnancy and those with gestational DM or hypertensive disorders, were excluded from the study. We compared the risk of future maternal outcomes (HTN and DM) according to the offspring’s birthweight. Multivariate analyses were performed to estimate the hazard ratio (HR) for the future risk of HTN or DM. Results: A total of 64,037 women were included in the analysis. Of these, women who delivered very LGA babies (birthweight > 97th percentile) were at a higher risk of developing DM than those who delivered appropriate-for-gestational-age (AGA) babies (adjusted HR = 1.358 [1.068–1.727]), and women who delivered very SGA babies (birthweight < 3rd percentile) were at a higher risk of developing HTN than those who delivered AGA babies (adjusted HR = 1.431 [1.181–1.734]), even after adjusting for age, parity, gestational age at delivery, fetal sex, maternal BMI score, and a history of smoking. Conclusion These findings provide a novel support for the use of the offspring’s birthweight as a predictor of future maternal diseases such as HTN and DM.

Background: We sought to identify the influence of prepregnancy glucose levels on obstetric complications in subsequent pregnancy. Methods: Women in Republic of Korea who had given birth between January 1st, 2007 and December 31st, 2010 were enrolled. The database of the Health Insurance Review and Assessment Service and data from a national health screening program for infants and children were used. Subjects were divided into seven groups according to their fasting glucose levels. Results: 59,619 women were included for analysis, and 10.4%, 13.7%, 19.1%, 21.5%, 16.0%, 11.6%, and 7.5% women had glucose levels of < 75, 75–79, 80–84, 85–89, 90–94, 95–100 and > 100 mg/dL. Each 5 mg/dL increase in prepregnancy fasting glucose levels was associated with increased risk of gestational diabetes and macrosomia in subsequent pregnancy. Adjusted risk ratio for gestational diabetes per standard deviation prepregnancy glucose > 100 mg/dL was 2.015 (95% confidence interval, 1.649–2.462) and for macrosomia an adjusted risk ratio 1.389 (95% confidence interval, 1.147–1.682). Conclusion Higher prepregnancy glucose level within normal range was related to gestational diabetes and macrosomia in following pregnancy. Our results may aid in the identification of women at future risk of obstetric complications and may guide to stratify women into normal and intensified care.Tweetable abstractHigher prepregnancy glucose in normal range is associated with gestational diabetes and macrosomia.

Objective: This study aimed to investigate trends in the rate of cesarean sections (CSs) in South Korea from 2006 to 2015 and identify the risk factors associated with these changes. Methods: Using the National Health Insurance Corporation dataset, all women who gave birth between 2006 and 2015 were included in the study. We investigated 1) the mode of delivery, 2) the complication rates during pregnancy (i.e., preeclampsia and placenta previa), and 3) pre-pregnancy factors (body mass index, hypertension [HTN], diabetes mellitus [DM], and other pre-existing medical conditions), and their trends during the study period. Results: Over 10 years, the rate of CS increased from 36.3% in 2006 to 40.6% in 2015 (P<0.01). The rate of CS increased in primiparous women, women with multiple pregnancy, and women with preeclampsia. Maternal age and the incidence of placenta previa also increased. In contrast, the rate of vacuum deliveries and vaginal birth after CS decreased during the study period. The rate of women with pre-pregnancy obesity and DM increased, but the rate of women with pre-pregnancy HTN decreased. Conclusion The rate of CS in South Korea increased from 2006 to 2015. This trend may reflect changes in the rate of different risk factors. Identifying the causes of the increasing CS trend observed in this study will allow clinicians to monitor these factors and possibly reduce the rate of CS.

Objective: This study aimed to investigate trends in the rate of cesarean sections (CSs) in South Korea from 2006 to 2015 and identify the risk factors associated with these changes. Methods: Using the National Health Insurance Corporation dataset, all women who gave birth between 2006 and 2015 were included in the study. We investigated 1) the mode of delivery, 2) the complication rates during pregnancy (i.e., preeclampsia and placenta previa), and 3) pre-pregnancy factors (body mass index, hypertension [HTN], diabetes mellitus [DM], and other pre-existing medical conditions), and their trends during the study period. Results: Over 10 years, the rate of CS increased from 36.3% in 2006 to 40.6% in 2015 (P<0.01). The rate of CS increased in primiparous women, women with multiple pregnancy, and women with preeclampsia. Maternal age and the incidence of placenta previa also increased. In contrast, the rate of vacuum deliveries and vaginal birth after CS decreased during the study period. The rate of women with pre-pregnancy obesity and DM increased, but the rate of women with pre-pregnancy HTN decreased. Conclusion The rate of CS in South Korea increased from 2006 to 2015. This trend may reflect changes in the rate of different risk factors. Identifying the causes of the increasing CS trend observed in this study will allow clinicians to monitor these factors and possibly reduce the rate of CS.

OBJECTIVE: This study aimed to determine the association between preeclampsia and the postpartum development of metabolic syndrome based on the pre-pregnancy status. METHODS: Korean women who delivered their first child between January 1, 2011, and December 31, 2012, were enrolled. All subjects underwent a national health screening examination conducted by the National Health Insurance Corporation 1 or 2 years prior to their first delivery and within 2 years after their first delivery. RESULTS: Among the 49,065 participants, preeclampsia developed in 3,391 participants (6.9%). The prevalence of metabolic syndrome was higher postpartum in women with preeclampsia than in those without preeclampsia (4.9% vs. 2.7%, respectively, P<0.001). Through the pre-pregnancy to postpartum period, women with preeclampsia had a greater increase in gestational weight retention, body mass index, waist circumference, systolic blood pressure, and triglyceride levels and a greater decrease in high-density lipoprotein cholesterol levels than women without preeclampsia. Preeclampsia was associated with an increased risk of the postpartum development of metabolic syndrome in women without pre-pregnancy metabolic syndrome (odds ratio, 1.28; 95% confidence interval, 1.05–1.56). However, preeclampsia was not associated with postpartum metabolic syndrome in women with pre-pregnancy metabolic syndrome or 2 components of metabolic syndrome. CONCLUSION: In this study, preeclampsia was associated with the postpartum development of metabolic syndrome in women without pre-pregnancy metabolic syndrome. However, the effects were attenuated by predisposing risk factors in the pre-pregnancy period.
Blood Pressure ; Body Mass Index ; Cardiovascular Diseases ; Child ; Cholesterol ; Diabetes Mellitus ; Female ; Humans ; Hypertension ; Lipoproteins ; Mass Screening ; National Health Programs ; Postpartum Period ; Pre-Eclampsia ; Prevalence ; Risk Factors ; Triglycerides ; Waist Circumference

BACKGROUND: Although preterm delivery is the most common cause of infant morbidity and mortality, an obvious cause cannot be found in most cases. Preterm delivery is known to be the most important risk factor for preterm birth in a subsequent pregnancy. We aimed to evaluate the recurrence rate of premature births for subsequent pregnancies in women with a history of a preterm birth. METHODS: Study data were collected from the Korea National Health Insurance (KNHI) claims database and data from a national health-screening program for infants and children. We enrolled women who had their first delivery between January 1, 2007 and December 31, 2007 and a subsequent delivery before 2014. RESULTS: Preterm delivery had a significant higher risk of preterm birth in a subsequent singleton pregnancy. The risk of preterm birth at second pregnancy was 2.2% in women whose first delivery at ≥ 37 weeks and 18.6% in women whose first delivery at 37 weeks (relative risks [RR], 8.64; 95% confidence interval [CI], 7.94–9.40). In the analysis of the third pregnancy, we compared women with an initial term birth followed by preterm birth and women with an initial preterm birth followed by a subsequent term birth. A history of a just preceding preterm birth at 37 weeks was the most relevant factor for recurrence of preterm delivery in a subsequent pregnancy (26.6%, RR, 4.01; 95% CI, 2.45–6.58). CONCLUSION: We found that the prognosis of a third pregnancy was more closely related to the outcome of the second pregnancy to that of the first pregnancy.
Child ; Female ; Humans ; Infant ; Korea* ; Mortality ; National Health Programs ; Pregnancy* ; Premature Birth* ; Prognosis ; Recurrence ; Risk Factors ; Term Birth

OBJECTIVE: The purpose of this study was to investigate the effects of estradiol on the expression of hypoxia-inducible factor (HIF)-1α and the differentiation of trophoblasts in human first trimester villous explant cultures. METHODS: Villous explant cultures were established from first trimester human placentas (6–8 weeks of gestation, n=3). Normal villous tissues were explanted on Matrigel and incubated under 3% O2 tension for 5 days. To evaluate the effects of estradiol on the villous explant cultures, 1 ng/mL of estradiol was added to the culture medium. The morphological integrities and viabilities of the villous explants were monitored. Immunohistochemistry for α5 and α1 integrin was performed to assess differentiation of extravillous trophoblasts (EVTs). Expression of HIF-1α in villous explant cultures was evaluated by western blotting and densitometry. RESULTS: EVTs emerging from first trimester villous explant cultures formed outgrowths of cells from the distal ends and invaded the surrounding Matrigel. Exposure of villous explants to estradiol resulted in the decreased outgrowth of cells from the distal end and decreased expression of α5 integrin. However, estradiol treatment increased the invasion of villous explants into the surrounding Matrigel, concomitant with the increased expression of α1 integrin, indicating differentiation of EVTs into more invasive EVTs. On western blots, the expression of HIF-1α decreased significantly after treatment with estradiol under 3% O2 tension. CONCLUSION: Our findings suggest that estradiol may downregulate expression of HIF-1α in placenta, which in turn promote trophoblast differentiation into invasive phenotype.
Blotting, Western ; Densitometry ; Estradiol ; Female ; Humans ; Immunohistochemistry ; Phenotype ; Placenta ; Pregnancy ; Pregnancy Trimester, First ; Trophoblasts

PURPOSE: The objective of the present study was to predict the gestational age at preterm birth using artificial neural networks for singleton pregnancy. METHODS: Artificial neural networks (ANNs) were used as a tool for the prediction of gestational age at birth. ANNs trained using obstetrical data of 125 cases, including 56 preterm and 69 non-preterm deliveries. Using a 36-variable obstetrical input set, gestational weeks at delivery were predicted by 89 cases of training sets, 18 cases of validating sets, and 18 cases of testing sets (total: 125 cases). After training, we validated the model by another 12 cases containing data of preterm deliveries. RESULTS: To define the accuracy of the developed model, we confirmed the correlation coefficient (R) and mean square error of the model. For validating sets, the correlation coefficient was 0.839, but R of testing sets was 0.892, and R of total 125 cases was 0.959. The neural networks were well trained, and the model predictions were relatively good. Furthermore, the model was validated with another dataset of 12 cases, and the correlation coefficient was 0.709. The error days were 11.58±13.73. CONCLUSION: In the present study, we trained the ANNs and developed the predictive model for gestational age at delivery. Although the prediction for gestational age at birth in singleton preterm birth was feasible, further studies with larger data, including detailed risk variables of preterm birth and other obstetrical outcomes, are needed.
Dataset ; Gestational Age ; Parturition ; Pregnancy ; Premature Birth

The issue exerting the greatest influence in Korea is the low birth rate. It is important, therefore, to examine the countermeasures taken, and their effectiveness, by other countries suffering a declining birth rate and consequent aging population before Korea. Such countries can be categorized according to their cultural background: the UK, Continental Europe, Scandinavia, and Asia. In Continental European countries, such as Germany and France, the employment rate of women is relatively low, whereas it is relatively high in the UK and Scandinavian countries. In Asian countries, such as Japan and Singapore, despite many policies instituting the work-family balance, a childcare infrastructure, and child allowance, little is being achieved, due to the specific culture of Asia and the social rejection of various family forms. However, it should not be forgotten that those countries succeeding in increasing the birth rate have implemented continuous policies for decades.
Aging ; Asia ; Asian Continental Ancestry Group ; Birth Rate ; Child ; Employment ; Europe ; Female ; France ; Germany ; Humans ; Japan ; Korea ; Parturition ; Scandinavian and Nordic Countries ; Singapore ; Social Distance

Although the prevalence of interracial marriages in Korea is increasing, little is known regarding the pregnancy outcomes of interracial couples. The aim of this study was to investigate the differences in pregnancy outcomes between Korean and interracial Korean-foreign couples. Data for infants born in 2011 and 2012 were obtained from the national birth registry of the Korean Statistical Office. The couples were subdivided into Korean father-Korean mother, Korean father-foreign mother, and foreign father-Korean mother groups. Pregnancy outcomes included neonates with low birth weight (< 2,500 g) and those with high birth weight (> 4,000 g). In 2010 and 2011, 888,447 Korean father-Korean mother, 36,024 Korean father-foreign mother, and 4,955 foreign father-Korean mother neonates were delivered in Korea. After adjustment for parental age, educational level, parity, gestational age at delivery, and neonatal sex, the birth weights were found to be different between groups, with the highest number of foreign father-Korean mother and lowest number of Korean father-foreign mother pregnancies. Based on multivariate logistic regression analysis, the risk of low and large birth weights was higher in the Korean father-foreign mother and foreign father-Korean mother groups, respectively, compared with that in the Korean father-Korean mother group. There are significant differences in pregnancy outcomes including birth weights between Korean and interracial Korean-foreign couples.
Birth Weight ; Family Characteristics* ; Female ; Gestational Age ; Humans ; Infant ; Infant, Low Birth Weight ; Infant, Newborn ; Korea* ; Logistic Models ; Marriage ; Mothers ; Parents ; Parity ; Parturition ; Pregnancy ; Pregnancy Outcome* ; Pregnancy* ; Prevalence