Prepregnancy Glucose Levels Within Normal Range and Its Impact on Obstetric Complications in Subsequent Pregnancy: A Population Cohort Study

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 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.

Secular trends in cesarean sections and risk factors in South Korea (2006–2015)

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.

Secular trends in cesarean sections and risk factors in South Korea (2006–2015)

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.

Addition of Cervical Elastography May Increase Preterm Delivery Prediction Performance in Pregnant Women with Short Cervix: a Prospective Study

BACKGROUND: We investigated whether there is a difference in elastographic parameters between pregnancies with and without spontaneous preterm delivery (sPTD) in women with a short cervix (≤ 25 mm), and examined the ability of elastographic parameters to predict sPTD in those women. METHODS: E-CervixTM (WS80A; Samsung Medison, Seoul, Korea) elastography was used to examine the cervical strain. Elastographic parameters were compared between pregnancies with and without sPTD. Diagnostic performance of elastographic parameters to predict sPTD ≤ 37 weeks, both alone and in combination with other parameters, was compared with that of cervical length (CL) using area under receiver operating characteristic curve (AUC) analysis. RESULTS: A total of 130 women were included. Median gestational age (GA) at examination was 24.4 weeks (interquartile range, 21.4–28.9), and the prevalence of sPTD was 20.0% (26/130). Both the elastographic parameters and CL did not show statistical difference between those with and without sPTD. However, when only patients with CL ≥ 1.5 cm (n = 110) were included in the analysis, there was a significant difference between two groups in elasticity contrast index (ECI) within 0.5/1.0/1.5 cm from the cervical canal (P < 0.05) which is one of elastographic parameters generated by E-Cervix. When AUC analysis was performed in women with CL ≥ 1.5 cm, the combination of parameters (CL + pre-pregnancy body mass index + GA at exam + ECI within 0.5/1.0/1.5 cm) showed a significantly higher AUC than CL alone (P < 0.05). CONCLUSION: An addition of cervical elastography may improve the ability to predict sPTD in women with a short CL between 1.5 and 2.5 cm.

Is preeclampsia itself a risk factor for the development of metabolic syndrome after delivery?

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.

Governmental Policies for Overcoming Low Birth Rate by Country

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.

Prediction of Gestational Age at Birth using an Artificial Neural Networks in Singleton Preterm Birth

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.

Preeclampsia Increases the Incidence of Postpartum Cerebrovascular Disease in Korean Population

BACKGROUND: Multiple studies have been reported regarding preeclampsia as a possible risk factor of cerebrovascular disease (CVD). However, the correlation of preeclampsia and CVD, whether it is a cause-effect relationship or they are sharing common predisposing condition, is not well understood. Therefore, the aim of this study was to investigate the association between the preeclampsia during pregnancy and development of postpartum CVD. METHODS: A total of 1,384,550 Korean women who had a delivery between January 1, 2010 and December 31, 2012, were enrolled. Women with the risk of CVD within 1 year prior to pregnancy were excluded based on the Charlson comorbidity index. Primary endpoint was the event of CVD within a year from delivery. After exclusion, 1,075,061 women were analyzed. RESULTS: During the follow-up of 1 year postpartum, there were 25,577 preeclampsia out of 1,072,041 women without postpartum CVD (2.39%), and 121 of 3,020 women with postpartum CVD had preeclampsia before delivery (4.01%). In multivariate logistic regression analysis, women who had preeclampsia during pregnancy showed a higher risk for postpartum CVD (odds ratio, 1.64; 95% confidence interval, 1.37–1.98). CONCLUSION: The incidence of CVD after delivery was higher in women who had preeclampsia during pregnancy.

Effects of estradiol on HIF-1α expression and trophoblast differentiation in first trimester villous explant cultures

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.

Recurrent Risk of Preterm Birth in the Third Pregnancy in Korea

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.

Association of citalopram with congenital anomalies: A meta-analysis

OBJECTIVE: The antenatal use of citalopram, a widely prescribed selective serotonin reuptake inhibitor, has been suspected to be associated with congenital, particularly cardiac, anomalies. This study aimed to prove the association between citalopram use and congenital anomalies. METHODS: We searched the English literature from July 1998 to July 2015, by using the search terms ‘ citalopram’, ‘ pregnancy’, ‘ birth defects’, ‘ congenital anomalies’, and ‘ malformations’ in PubMed, Embase, Web of Science, and the Cochrane Library. RESULTS: Eight eligible articles were analyzed including a total of 1,507,896 participants. The odds ratio (OR) of major malformations associated with citalopram use during pregnancy was 1.07 (95% confidence interval [CI], 0.98 to 1.17). Concerning cardiac malformations, the OR for all included studies was 1.31 (95% CI, 0.88 to 1.93). The analysis of cardiac malformations was repeated to reduce heterogeneity after excluding one outlier study (OR, 1.03; 95% CI, 0.84 to 1.26). CONCLUSION: From our data, it can be concluded that citalopram use is not associated with major birth defects. However, physicians should carefully weigh the benefits against the potential risks of citalopram use, and counsel patients accordingly.

Analysis of Pregnancy Outcomes among Interracial Couples in Korea

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 ( 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.

The Health Behavior and Status according to Household Income Level in Korean Women Aged 35 Years or Older: the 2013 National Health and Nutrition Examination Survey

BACKGROUND: Income is a major socioeconomic index, and low household income is known to negatively affect health. Nevertheless, there is a lack of research on the health status and health behavior of middle-aged and older women with low-income. This study aims to provide basic information on the health status and health behavior of low-income women, using data representative of South Koreans. METHODS: This cross-sectional study used data from the 6th Korea National Health and Nutrition Examination Survey. Among the total of 8,018 respondents, 2,713 women aged 35 years or older were enrolled in the study. The subjects were classified by income status based on standard household income quartiles. RESULTS: The low-income group showed the lowest education levels and the highest unemployment rate (P<0.001). The percentage of smokers was the highest, while the frequency of exercise was the lowest in this group (P<0.001). The incidence of hyperlipidemia was highest (P=0.028), and they showed the highest body mass index, waist circumference (P<0.001), blood pressure, fasting blood glucose (P=0.018), and triglyceride level (P=0.03), as well as the lowest high density lipoprotein level (P=0.039), and the highest risk of cardiovascular diseases (P=0.002). Additionally, perceived health status was negative and quality of life was lowest among the groups (P<0.001). Although the enrollment rate for free health check-up services was highest (P=0.007), subscription to private health insurance, adult health check-ups, cancer screening rate were all lowest of the groups. CONCLUSIONS: This study confirmed a health gap among middle-aged and elderly women of low income, compared to higher income groups.

Vaccination in pregnancy

Over the past few decades, eradication and reduction of vaccine-preventable diseases through immunization has increased life expectancy by reducing mortality. Pregnant women are at risk for vaccine-preventable disease-related morbidity and mortality and adverse pregnancy outcomes, including congenital anomalies, spontaneous abortion, preterm birth, and low birth weight. In addition to providing direct maternal benefit, vaccination during pregnancy likely provides direct fetal and neonatal benefit through passive immunity. Despite the impact of immunization, vaccination in pregnancy is still inadequate. This article reviews types of vaccine and vaccines recommended during pregnancy.

Seasonal Pattern of Preterm Births in Korea for 2000–2012

The aim of this study was to investigate a seasonal pattern of preterm births in Korea. Data were obtained from the national birth registry of the Korean Statistics Office and included all births in Korea during the period 2000–2012 (n = 6,310,800). Delivery dates were grouped by month of the year or by season (winter [December, January, February], spring [March, April, May], summer [June, July, August], and autumn [September, October, November]). The seasonal patterns of prevalence of preterm births were assessed. The rates of preterm births at 37 weeks were highest twice a year (once in winter and again in summer). The rates of preterm births increased by 13.9% in summer and 7.5% in winter, respectively, than in spring (OR, 1.139; 95% CI, 1.127–1.152, and OR, 1.075; 95% 1.064–1.087, respectively) after controlling for age, the educational level of the parents, maternal parity, and neonatal gender. The pattern for spontaneous preterm births < 34 weeks was similar. In Korea, a seasonal pattern of preterm births was observed, with peak prevalence in summer and winter. A seasonal pattern of preterm births may provide new insights for the pathophysiology of preterm births.

Adaptive responses of cardiac function to fetal postural change as gestational age increases

OBJECTIVE: The cardiovascular system maintains homeostasis through a series of adaptive responses to physiological requirements. However, little is known about the adaptation of fetal cardiac function to gravity, according to gestational age. In the present study, we aimed to evaluate the adaptive responses of cardiac function to postural changes, using Tei index measurements. METHODS: Fetal echocardiography and Doppler examination were performed on 114 women with vertex singleton pregnancies at 19 to 40 weeks' gestation. Participants were placed in an upright seated position, and the Tei index for fetal left ventricular cardiac function was measured. The women were then moved into a supine position and the Tei index was re-measured. RESULTS: The mean Tei index when measured in an upright seated position was significantly lower than that measured in a supine positioning for all fetuses (0.528±0.103 vs. 0.555±0.106, P=0.014, respectively). This difference was also noted in fetuses with a gestational age of 28–40 weeks (0.539±0.107 vs. 0.574±0.102, P=0.011, respectively). However, there was no difference in the Tei index between an upright seated and a supine position among fetuses with a gestational age of <28 weeks (0.505±0.091 vs. 0.516±0.103, P=0.571, respectively). CONCLUSION: Postural changes from an upright seated to a supine position result in an increased Tei index after a gestational age of 28 weeks. This appears to reflect maturation in the adaptive responses of the fetal cardiovascular system to postural changes.

2014 First-trimester ultrasound forum from the Korean Society of Ultrasound in Obstetrics and Gynecology

A first-trimester ultrasound scan has become an essential part of antenatal care. The Korean Society of Ultrasound in Obstetrics and Gynecology held a first-trimester ultrasound forum on April 5, 2014. The forum aimed to present an updated review of the literature on the topic of first-trimester ultrasound in specific lectures and to host a panel discussion on several important issues regarding first-trimester scans. The forum provided evidence- and consensus-based best practice patterns for obstetricians in Korea. Here, we report the review and checklists presented from the forum.

Comparison of the effects of gestational weight gain on pregnancy outcomes between non-diabetic and diabetic women

OBJECTIVE: Appropriate gestational weight gain (GWG) is important in diabetic women. Current GWG guideline is for US general population, but not specific for diabetic women. We compared the effect of GWG on perinatal outcomes between diabetic and non-diabetic women. METHODS: Fifty two hundred and twelve women who delivered live singleton infants at Korea University Medical Center from January 2009 to December 2013 were included. One hundred twenty-nine overt diabetes women and 322 gestational diabetes women were categorized as diabetic women, and the others were categorized as none-diabetic women. 5,212 women were categorized by GWG (low 1,081; adequate 2,102; or high 2,029; according to the 2009 Institute of Medicine guidelines), and each of the 3 GWG groups was categorized into 2 groups; diabetic or non-diabetic women. And then, we compared perinatal outcomes between diabetic and non-diabetic groups. RESULTS: In each 3 GWG groups, primary cesarean section delivery, high birth weight, and large for gestational age rates were significantly higher in diabetic women than non-diabetic women. Only in adequate GWG group, preterm birth rate was significantly higher in diabetic women than non-diabetic women. CONCLUSION: Our study shows that diabetic women had higher rates of adverse perinatal outcomes than non-diabetic women, although they achieved same GWG. It suggests that current GWG guideline may not be adequate for diabetic women, and that diabetic women may need more strict GWG control than normal population.

Placental expression of D6 decoy receptor in preeclampsia

OBJECTIVE: The purpose of this study was to investigate the expression of the D6 decoy receptor that can bind chemokines and target them for degradation, resulting in inhibition of inflammation in placentas from preeclamptic and normal pregnancies. METHODS: The current study was carried out in 35 pregnant women (23 patients with preeclampsia and 12 healthy, normotensive pregnant women) during the third trimester of pregnancy. The expressions of D6 decoy receptor in the placenta were determined with real time reverse transcriptase polymerase chain reaction and western blotting. RESULTS: The mRNA and protein of D6 decoy receptor were detected in all of placentas from preeclamptic and normal pregnancies. Placental D6 decoy receptor mRNA expression was significantly lower in patients with preeclampsia than in patients with normal pregnancies. Western blot analyses revealed decreased protein expression in cases of preeclampsia. CONCLUSION: The expression of the D6 decoy receptor in preeclamptic placentas was significantly lower than in normal placentas. Further studies are needed to clarify the underlying mechanisms that link decreased expression of placental D6 decoy receptor and preeclampsia.

Intrapartum ultrasound: A useful method for evaluating labor progress and predicting operative vaginal delivery

The last step of a successful pregnancy is the safe delivery of the fetus. An important question is if the delivery should vaginal or operative. In addition to the use of conventional antenatal ultrasound, the use of intrapartum ultrasound to evaluate fetal head station, position, cervical ripening, and placental separation is promising. This review evaluates and summarizes the usefulness of intrapartum ultrasound for the evaluation of labor progress and predicting successful operative vaginal delivery.