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

A Possible Role of Clinical Factors in Choosing the Best Treatment Modality in Cesarean Scar Pregnancy

Background/Objectives: Cesarean scar pregnancy (CSP) refers to a pregnancy implanted on or within a scar from a previous cesarean birth. This study aims to evaluate the treatment strategies for CSP conducted at a single center and analyze the predictive markers of a single procedure without complications. Methods: A retrospective study was performed on CSP patients who received treatment at Korea University Ansan Hospital from November 2002 to December 2022. The clinical characteristics of CSP and the occurrence of complications based on treatment methods were investigated. Results: A total of 128 patients were included in the study. Among them, 84 patients (65.6%) underwent dilatation and curettage (D&C) only, 12 patients (9.4%) received a combination of methotrexate and D&C, 21 received D&C with Foley catheter ballooning (15.7%), and 11 patients (9%) underwent invasive procedures such as uterine artery embolization, hysterectomy, and open resection. As gestational age increased, the likelihood of opting for invasive procedures (aOR = 3.52, 95% CI 1.74-10.14, p = 0.003) also increased. A total of 84 patients (65.6%) were successfully treated with D&C without transfusion, and it was found that early gestational age and sonographic hypervascularity played a significant role. Conclusions: Early gestational age, younger maternal age, and sonographic hypervascularity were independently associated with favorable treatment without adjuvant therapy and transfusion. Therefore, for a safe and bloodless approach to treatment in cases of CSP, it is advisable to promptly diagnose this condition as early as possible.

Is a rising cesarean delivery rate explained by late birth trend? A decomposition analysis of health insurance claims data (2013-2022) from South Korea

OBJECTIVE

To analyze the factors influencing the increase in the cesarean delivery (CD) rate in South Korea and test the hypothesis on advanced maternal age driving the trend.

METHOD

The present study is a population-based retrospective observational study utilizing administrative data from the Korean National Health Insurance Service. We analyzed a total 3 416 517 births from 2013 to 2022 covered by the national health insurance. The CD rate and contribution of demographic variables to changes in CD rates were calculated using Das Gupta's decomposition method.

RESULTS

The CD rate increased from 37.8% in 2013 to 61.6% in 2022. The decomposition analysis revealed that changes in maternal age structure contributed only 8.7% to the increase in the CD rate. When parity was added to maternal age, the explained proportion increased to 17.8%. When other factors were added to the model, such as multiple births, residential area, and income level, it did not contribute significantly to the increase in the CD rates, accounting for 19.0%, 18.6%, and 18.0%, respectively.

CONCLUSIONS

According to our analysis, less than one-fifth of the increase in CD rate was explained by the change in maternal age. The rising CD rate in Korea should not be considered an unavoidable consequence of demographic change. Much more diverse factors, including increased risk of medical lawsuits, changes in childbirth culture, and other health system determinants, may be driving the trend.

Trends, statistics, and policy recommendations on maternal, fetal, and infant mortality before and after COVID-19: a review of the past decade (2012-2022) based on national health information data

OBJECTIVE

To examine the impact of the coronavirus disease 2019 (COVID-19) pandemic on maternal, fetal, and infant mortality in South Korea using national statistics, in order to inform policy development and enhance maternal and child health outcomes with the provided data.

METHODS

Pregnancy-related mortality in women, as well as deaths of infants, in South Korea was identified using cause-of-death statistics from Statistics Korea. Records from death certificates, cremation reports on infant and fetal deaths, and the complementary cause-of-death investigation system were reviewed for the 2012-2022 period. The classification criteria for cause of death followed the recommendations of World Health Organization and the Korean standard classification of diseases and causes of death.

RESULTS

The maternal mortality rate decreased from 11.3 per 100,000 live births in 2018 to 9.9 in 2019, rose to 11.8 in 2020, and fell to 8.8 in 2021. The actual number of maternal deaths declined from 37 in 2018 to 23 in 2021 due to fewer births. The fetal death rate increased from 11.3 per 1,000 live births in 2018 to 11.6 in 2019, continuing to rise to 12.0 in 2021. The number of fetal deaths dropped from 3,743 in 2018 to 3,152 in 2021.

CONCLUSION

Despite the COVID-19 pandemic, Korea experienced a sharp decline in births as well as in maternal, infant, and fetal deaths. However, maternal, infant, and fetal mortality rates remained at similar levels.

Pregnancy related complications in women with hypertrophic cardiomyopathy: a nationwide population-based cohort study

BACKGROUND

The impact of hypertrophic cardiomyopathy (HCM) on cardiovascular and obstetrical outcomes in pregnant women remains unclear, particularly in Asian populations. This study aimed to evaluate the maternal cardiovascular and obstetrical outcomes in Korean women with HCM.

METHODS

Using data from the Korean National Health Insurance Service database, we identified women who gave birth via cesarean section or vaginal delivery after being diagnosed with HCM between 2006 and 2019. Maternal cardiovascular and obstetrical outcomes were assessed based on the trimester of pregnancy.

RESULTS

This study included 122 women and 158 pregnancies. No maternal deaths were noted; however, 21 cardiovascular events, such as hospital admission for cardiac problems, including heart failure and atrial fibrillation (AF), new-onset AF or ventricular tachycardia (VT) occurred in 14 pregnancies (8.8%). Cardiac events occurred throughout pregnancy with a higher occurrence in the third trimester. Cesarean sections were performed in 49.3% of the cases, and all cardiovascular outcomes occurring after delivery were observed in patients who had undergone cesarean sections. Seven cases involved preterm delivery, and two of these cases were accompanied by cardiac events, specifically AF. Pre-existing arrhythmia (AF: odds ratio (OR): 7.44, 95% confidence interval (CI): 2.61-21.21, P < 0.001; VT: OR: 31.61, 95% CI: 5.85-172.77, P < 0.001) was identified as a predictor for composite outcomes of cardiovascular events or preterm delivery.

CONCLUSIONS

Most pregnant women with HCM were well-tolerated. However, cardiovascular complications could occur in some patients. Therefore, planned delivery may be necessary for selected patients, especially the women with pre-existing arrhythmias.

Risk factors for postpartum hemorrhage in twin pregnancies with cesarean section

The rates of twin pregnancies and cesarean section have increased in recent years, and both of them are at high risks of postpartum hemorrhage (PPH). However, few studies have concentrated on the risks of PPH in twin pregnancies and cesarean deliveries. In this study, we aimed to identify the risk factors for PPH among twin-pregnant women with cesarean section. This was a retrospective observational study including 1,649 women with twin pregnancies delivered by cesarean section from 2016 to 2022 in the Second Affiliated Hospital of Wenzhou Medical University, China. The eligible women were divided into PPH group (n = 116) and non-PPH group (n = 1,533) according to the blood loss after delivery within 24 h. The baseline maternal and perinatal characteristics were compared between the two groups. Logistic regression analysis was conducted to identify the potential risk factors for PPH. We found nulliparity, assisted reproductive technology (ART) usage, preeclampsia or HELLP syndrome, placenta previa, placenta accreta and general anesthesia were more common in PPH group than non-PPH group (P < 0.05). Women in PPH group had higher maternal body mass index at delivery and higher combined birthweight of the twins than non-PPH group, but had lower parity (P < 0.05). Seven independent risk factors for PPH were identified after logistic regression analysis: ART usage (OR 2.354 95% CI 1.357-4.083, P = 0.002), preeclampsia or HELLP syndrome (OR 2.605, 95% CI 1.471-4.616, P = 0.001), placenta previa (OR 7.325, 95% CI 3.651-14.697, P < 0.001), placenta accreta (OR 6.296, 95% CI 1.316-30.12, P = 0.021), thrombocytopenia (OR 1.636, 95% CI 1.056-2.535, P = 0.027), general anesthesia (OR 2.394, 95% CI 1.223-4.686, P = 0.011), and combined birthweight (OR 1.00032, 95% CI 1.00005-1.00059, P = 0.020). Collectively, in women with twin pregnancies delivered by cesarean section, the use of ART, preeclampsia or HELLP syndrome, placenta previa, placenta accreta, thrombocytopenia, general anesthesia and the combined birthweight were identified as independent risk factors for PPH. More attention should be paid to women with these risk factors.

Prediction of Pregnancy-Associated Hypertension Using a Scoring System: A Multicenter Cohort Study

This study aimed to develop an early pregnancy risk scoring model for pregnancy-associated hypertension (PAH) based on maternal pre-pregnancy characteristics, such as mean arterial pressure (MAP), pregnancy-associated plasma protein-A (PAPP-A) or neither. The perinatal databases of seven hospitals from January 2009 to December 2020 were randomly divided into a training set and a test set at a ratio of 70:30. The data of a total pregnant restricted population (women not taking aspirin during pregnancy) were analyzed separately. Three models (model 1, pre-pregnancy factors only; model 2, adding MAP; model 3, adding MAP and PAPP-A) and the American College of Obstetricians and Gynecologists (ACOG) risk factors model were compared. A total of 2840 (8.11%) and 1550 (3.3%) women subsequently developed PAH and preterm PAH, respectively. Performances of models 2 and 3 with areas under the curve (AUC) over 0.82 in both total population and restricted population were superior to those of model 1 (with AUCs of 0.75 and 0.748, respectively) and the ACOG risk model (with AUCs of 0.66 and 0.66) for predicting PAH and preterm PAH. The final scoring system with model 2 for predicting PAH and preterm PAH showed moderate to good performance (AUCs of 0.78 and 0.79, respectively) in the test set. "A risk scoring model for PAH and preterm PAH with pre-pregnancy factors and MAP showed moderate to high performances. Further prospective studies for validating this scoring model with biomarkers and uterine artery Doppler or without them might be required".

Changes in preterm birth and birthweight during the SARS-CoV-2 pandemic: a nationwide study in South Korea

Birthweight is a strong determinant of a neonate’s health. The SARS-CoV-2 pandemic’s impact on birthweight has not been investigated in-depth, with inconsistent conclusions from initial studies. To assess changes in preterm birth and inappropriate birthweight between the SARS-CoV-2 pandemic and pre-pandemic periods. A nationwide birth micro-data consisted with exhaustive census of all births in 2011–2020 in South Korea was accessed to examine whether the mean birthweight and rates of under/overweight births changed significantly during the SARS-CoV-2 pandemic year (2020) compared to those of the pre-pandemic period (2011–2019). A total of 3,736,447 singleton births were analyzed. Preterm birth was defined as < 37 weeks of gestation. Low birthweight (LBW) and macrosomia were defined as birthweights < 2.5 kg and ≥ 4.0 kg, respectively. Small for gestational age (SGA) and large for gestational age (LGA) were defined as birthweights below the 10th and above 90th percentiles for sex and gestational age, respectively. Inappropriate birthweight was defined as one or more LBW, macrosomia, SGA, or LGA. Generalized linear models predicted birth outcomes and were adjusted for parental age and education level, marital status, parity, gestational age, and months from January 2011. There were 3,481,423 and 255,024 singleton births during the pre-pandemic and pandemic periods, respectively. Multivariable generalized linear models estimated negative associations between the pandemic and preterm birth (odds ratio [OR], 0.968; 95% confidence interval [CI] 0.958–0.978), LBW (OR: 0.967, 95% CI 0.956–0.979), macrosomia (OR: 0.899, 95% CI 0.886–0.912), SGA (OR: 0.974, 95% CI 0.964–0.983), LGA (OR: 0.952, 95% CI 0.945–0.959), and inappropriate birthweight (OR: 0.958, 95% CI 0.952–0.963), indicating a decline during the pandemic compared to pre-pandemic period. An 8.98 g decrease in birthweight (95% CI 7.98–9.99) was estimated during the pandemic. This is the largest and comprehensive nationwide study to date on the impact of the SARS-CoV-2 pandemic on preterm birth and inappropriate birthweight. Birth during the pandemic was associated with lower odds of being preterm, underweight, and overweight. Further studies are required to understand the dynamics underlying this phenomenon.

Non-invasive continuous blood pressure monitoring using the ClearSight system for pregnant women at high risks of post-partum hemorrhage: comparison with invasive blood pressure monitoring during cesarean section

Objective

This study aimed to investigate the accuracy and precision of continuous, non-invasive blood pressure obtained using the ClearSight system by comparing it with invasive arterial blood pressure, and to assess the hemodynamic changes using the ClearSight system in patients undergoing cesarean section.

Methods

Arterial pressure was measured invasively with an intra-arterial catheter and non-invasively using the ClearSight system during cesarean section in patients with placenta previa or placenta accreta. Blood pressure measurements obtained using these two means were then compared.

Results

Total 1,277 blood pressure measurement pairs were collected from 21 patients. Under Bland-Altman analysis, the ClearSight system demonstrated an acceptable accuracy with a bias and standard deviation of 8.8±13.4 mmHg for systolic blood pressure, -6.3±7.1 mmHg for diastolic blood pressure, and -2.7±8.0 mmHg for median blood pressure. Cardiac index levels were significantly elevated during fetal delivery and 5 minutes after placental removal, and systemic vascular resistance index levels were significantly decreased during fetal delivery and 40 minutes after placental removal.

Conclusion

In patients undergoing cesarean section, the ClearSight system showed excellent accuracy and precision compared to that of the currently used invasive monitoring system.

Prediction of Emergency Cesarean Section Using Machine Learning Methods: Development and External Validation of a Nationwide Multicenter Dataset in Republic of Korea

This study was a multicenter retrospective cohort study of term nulliparous women who underwent labor, and was conducted to develop an automated machine learning model for prediction of emergent cesarean section (CS) before onset of labor. Nine machine learning methods of logistic regression, random forest, Support Vector Machine (SVM), gradient boosting, extreme gradient boosting (XGBoost), light gradient boosting machine (LGBM), k-nearest neighbors (KNN), Voting, and Stacking were applied and compared for prediction of emergent CS during active labor. External validation was performed using a nationwide multicenter dataset for Korean fetal growth. A total of 6549 term nulliparous women was included in the analysis, and the emergent CS rate was 16.1%. The C-statistics values for KNN, Voting, XGBoost, Stacking, gradient boosting, random forest, LGBM, logistic regression, and SVM were 0.6, 0.69, 0.64, 0.59, 0.66, 0.68, 0.68, 0.7, and 0.69, respectively. The logistic regression model showed the best predictive performance with an accuracy of 0.78. The machine learning model identified nine significant variables of maternal age, height, weight at pre-pregnancy, pregnancy-associated hypertension, gestational age, and fetal sonographic findings. The C-statistic value for the logistic regression machine learning model in the external validation set (1391 term nulliparous women) was 0.69, with an overall accuracy of 0.68, a specificity of 0.83, and a sensitivity of 0.41. Machine learning algorithms with clinical and sonographic parameters at near term could be useful tools to predict individual risk of emergent CS during active labor in nulliparous women.

Epidemiologic study of bladder and urethral injury in Korea: A nationwide population-based study

Purpose

We aimed to analyze the characteristics and management of bladder and urethral injuries in Korea by use of the National Health Insurance Service (NHIS) database.

Materials and Methods

Data from the NHIS database representative of all cases of Korean bladder injury (n=4,631) and urethral injury (n=17,858) reported between 2012 and 2016 were analyzed. We used the International Classification of Diseases, 10th revision, clinical modification codes to identify the diagnoses.

Results

A total of 491 males (1.97/100,000) and 590 females (2.39/100,000) experienced bladder injury in 2012, and 449 males (1.76/100,000) and 624 females (2.47/100,000) in 2016. The risk of bladder injury was higher in female than in male (hazard ratio [HR], 1.267; p<0.001). The annual incidence of bladder injury did not increase (HR, 0.992; p=0.409). A total of 2,886 (62.3%) patients were managed with conservative treatment, and 1,745 (37.7%) patients underwent surgical treatment. A total of 4,114 males (16.5/100,000) and 285 females (1.2/100,000) had urethral injury in 2012, while 4,465 males (17.5/100,000) and 303 females (1.2/100,000) had urethral injury in 2016. The incidence of urethral injury is increasing annually (HR, 1.010; p=0.036).

Conclusions

The incidence of urethral injury increased continuously over the years studied, whereas that of bladder injury remained unchanged in Korea. The incidence of bladder injury was higher in females, and more than 90% of total urethral injuries were reported in males. This is the first study to evaluate the epidemiology of bladder and urethral injury using a nationwide population database.

Pregnancy outcomes in twin pregnancies over 10 years

OBJECTIVE

The aim of this study was to evaluate the changes in twin pregnancy outcomes between 2007 and 2016 in a Korean population.

METHODS

The data for this nationwide population-based study was obtained from the national birth registry of the Korean National Statistical Office and the Health Insurance Review & Assessment Service of Korea. Women with twin pregnancies who gave birth between 2007 and 2016 were included.

RESULTS

From 2007 to 2016, the rate of twin pregnancies increased (1.37% vs. 1.91%, respectively, P<0.0001). The risk of preterm birth (adjusted odds ratio [aOR], 1.77; 95% confidence interval [CI], 1.66-1.89) also increased; however, the risk of twin growth discordance (aOR, 0.90; 95% CI, 0.82-0.99) decreased. The risks of cesarean section (aOR, 1.16; 95% CI, 1.03-1.29), gestational diabetes mellitus (aOR, 2.10; 95% CI, 1.83-2.39), and postpartum hemorrhage (aOR, 1.27; 95% CI, 1.14-1.41) all increased from 2007 to 2016.

CONCLUSION

Twin pregnancy outcomes have changed significantly in Korea over a recent 10-year period.

Maternal pre-pregnancy underweight and the risk of small-for-gestational-age in Asian-American ethnic groups

Objective

This study aimed to examine the association between maternal pre-pregnancy underweight and the risk of small-for-gestational-age (SGA) birth among Asian Americans compared with non-Hispanic (NH) whites.

Methods

Using 2014–2018 birth data, we categorized maternal underweight and SGA according to severity. Bivariate analyses were performed to examine the demographics and maternal body mass index (BMI). Adjusted logistic regression models were used to analyze the association between maternal BMI and SGA among Asian Americans compared with NH-Whites.

Results

In Asian Americans, the likelihood of SGA birth was higher among underweight mothers than among mothers with a normal BMI (odds ratio [OR], 1.37; 95% confidence interval [CI], 1.30-1.46). We observed that as the severity of maternal underweight increased, the adjusted odds of SGA increased. Underweight Asian American mothers were more likely to give birth to SGA infants than underweight NH-White mothers (OR, 1.36; 95% CI, 1.28-1.44).

Conclusion

This study shows the association between maternal underweight and SGA birth among Asian Americans, supporting the development of culture-sensitive interventions addressing the impact of weight on pregnancy.

After 20 years of low fertility, where are the obstetrician-gynecologists?

Korea has entered a stage of low fertility, with a total fertility rate of 1.178 in 2002 and 0.92 in 2019. The low birth rate has led to the closure of obstetric hospitals and clinics from 1,371 maternity health facilities in 2003 to 541 in 2019, which is 39.5% compared to 2003. Since 2011, the Ministry of Health and Welfare has been operating an “Obstetrically Underserved Areas Support Project,” however, a shortage of obstetrician-gynecologists (OB/GYNs) who can participate in labor and delivery is a major problem. In 2019, there were 5,800 OB/GYNs practicing. Of these, 4,225 (72.8%) were working in obstetrics-gynecology hospitals, each responsible for 2,855 fertile women. Their average age was 51.8 years. A total of 2,659 (45.9%) worked in clinics and 3,110 (73.6%) were working in metropolitan districts. Only 124 OB/GYNs (2.9%) worked in vulnerable rural areas. OB/GYNs working in obstetric hospitals were responsible for 113.8 newborns in 2019. Their average age was 50.1 years. Of them, 67.4% were working in hospitals, 74.1% in urban areas, and only 60 specialists (2.3%) were working in rural areas. To establish a safe childbirth environment during an era of low fertility, it is important to have obstetricians in charge of childbirth. The government should establish a comprehensive long-term plan to resolve the shortage of OB/GYNs.