• Clinical and Experimental Reproductive Medicine
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• v.48 no.2
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• pp.174-183
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• 2021

Objective: The aim of this study was to compare the pregnancy outcomes of in vitro fertilization with embryo transfer between embryos cultured in a time-lapse monitoring system (TLS) and those cultured in a conventional incubator (CI). Methods: The medical records of 250 fertilized embryos from 141 patients undergoing infertility treatment with assisted reproductive technology at a tertiary hospital from June 2018 to May 2020 were reviewed. The study population was divided into TLS and CI groups at a 1 to 1 ratio (125 embryos per group). The primary outcome was the live birth rate. Results: The TLS group had a significantly higher clinical pregnancy rate (46.4% vs. 27.2%, p=0.002), implantation rate (27.1% vs. 12.0%, p=0.004), and live birth rate (32.0% vs. 18.4%, p=0.013) than the CI group. Furthermore, subgroup analyses of the clinical pregnancy rate and live birth rate in the different age groups favored the TLS group. However, this difference only reached statistical significance in the live birth rate in women aged over 40 years and the clinical pregnancy rate in women aged 35-40 years (p=0.048 and p=0.031, respectively). The miscarriage rate, cleavage rate, and blastocyst rate were comparable. Conclusion: TLS application improved the live birth rate, implantation rate, and clinical pregnancy rate, particularly in the advanced age group in this study, while the other reproductive outcomes were comparable. Large randomized controlled trials are needed to further explore the ramifications of these findings, especially in different age groups.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.2
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• pp.111-117
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• 2017

Objective: The aim of this study was to evaluate pregnancy outcomes and the live birth rate at 1-year age increments in women aged ${\geq}40years$ undergoing fresh non-donor in vitro fertilization (IVF) and embryo transfer (ET), and to identify predictors of success in these patients. Methods: This retrospective study was performed among women ${\geq}40years$ of age between 2004 and 2011. Of the 2,362 cycles that were conducted, ET was performed in 1,532 (73.1%). Results: The clinical pregnancy rate and live birth rate in women ${\geq}40years$ significantly decreased with each year of increased age (p<0.001). Maternal age (odds ratio [OR], 0.644; 95% confidence interval [CI], 0.540-0.769; p<0.001), basal follicle-stimulating hormone (FSH) levels (OR, 0.950; 95% CI, 0.903-0.999; p=0.047), the number of high-quality embryos (OR, 1.258; 95% CI, 1.005-1.575; p=0.045), and the number of transferred embryos (OR, 1.291; 95% CI, 1.064-1.566; p=0.009) were significant predictors of live birth. A statistically significant increase in live birth rates was seen when ${\geq}3$ embryos were transferred in patients 40 to 41 years of age, whereas poor pregnancy outcomes were seen in patients ${\geq}43years$ of age, regardless of the number of transferred embryos. Moreover, the cumulative live birth rate increased in patients 40 to 42 years of age with repeated IVF cycles, but the follicle-stimulating hormone in those ${\geq}43years$ of age rarely showed an increase. Conclusion: IVF-ET has acceptable outcomes in those < 43 years of age when a patient's own oocytes are used. Maternal age, basal FSH levels, and the number of high-quality embryos and transferred embryos are useful predictors of live birth.

• Clinical and Experimental Reproductive Medicine
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• v.49 no.3
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• pp.185-195
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• 2022

Objective: This study aimed to determine the effect of sperm DNA fragmentation (SDF) on the cumulative live birth rate (CLBR) in intracytoplasmic sperm injection (ICSI) cycles in couples with unexplained infertility. Methods: We conducted a prospective study of 145 couples who underwent ICSI cycles for unexplained infertility. Based on the SDF rate, patients were categorized into a low SDF group (SDF ≤30%, n=97) and a high SDF group (SDF >30%, n=48). SDF was assessed using the acridine orange test on density gradient centrifugation prepared samples. The CLBR was calculated as the first live birth event per woman per egg collection over 2 years. Results: The high SDF group (SDF >30%) showed a significantly lower CLBR (p<0.05) and a significantly higher miscarriage rate (p<0.05) than the low SDF group (SDF ≤30%). No significant difference was observed in the implantation and cumulative pregnancy rates between the two SDF groups. The total number of embryo transfers was stratified further into fresh and frozen embryo transfers. In the fresh embryo transfers, there were significant differences in the implantation rates, clinical pregnancy rates, and live birth rates (p<0.05) between the low SDF and high SDF groups. However, in the frozen embryo transfers, there were no significant differences in clinical outcomes between the two groups. In the multivariable logistic regression analysis, SDF was a predictor of CLBR (p<0.05) when adjusted for possible confounding factors. Conclusion: High SDF was associated with a lower CLBR and a higher miscarriage rate in the ICSI cycles of couples with unexplained infertility.

• Clinical and Experimental Pediatrics
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• v.54 no.11
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• pp.429-435
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• 2011

Although Korean population has been growing steadily during the past four decades, the nation is rapidly becoming an aging society because of its declining birth rate combined with an increasing life expectancy. In addition, Korea has one of the lowest fertility rates in the world due to fewer married couples, advanced maternal age, and falling birth rate. The prevalence of low birth weight infants and multiple births has been increased compared with the decrease in the birth rate. Moreover, the number of congenital anomalies is expected to increase due to the advanced maternal age. In addition, the number of interracial children is expected to increase due to the rise in the number of international marriages. However, the maternal education level is high, single-mother birth rate is low, and the gender imbalance has lessened. The number of overweight babies has been decreased, as more pregnant women are receiving adequate prenatal care. Compared to the Asian average birth weight, the average birth weight is the highest in Asia. Moreover, the rate of low birth weight infants is low, and infant mortality is similarly low across Asia. Using birth data from Statistics Korea and studies of birth outcomes in Korea and abroad, this study aimed to assess the changes in maternal and infant characteristics associated with birth outcomes during the past four decades and identify necessary information infrastructures to study countermeasures the decrease in birth rate and increase in low birth weight infants in Korea.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.3
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• pp.255-261
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• 2021

Objective: This study aimed to investigate sperm motility and its changes after preparation as predictors of pregnancy in intrauterine insemination (IUI) cycles. Methods: In total, 297 IUI cycles from January 2012 to December 2017 at a single tertiary hospital were retrospectively analyzed. Patient and cycle characteristics, and sperm motility characteristics before and after processing were compared according to clinical pregnancy or live birth as outcomes. Results: The overall clinical pregnancy rate per cycle was 14.5% (43/297) and the live birth rate was 10.4% (30/289). Patient and cycle characteristics were similar between pregnant and non-pregnant groups. Sperm motility after preparation and the total motile sperm count before and after processing were comparable in terms of pregnancy outcomes. Pre-preparation sperm motility was significantly higher in groups with clinical pregnancy and live birth than in cycles not resulting in pregnancy (71.4%±10.9% vs. 67.2%±11.7%, p=0.020 and 71.6% ±12.6% vs. 67.3%±11.7%, p=0.030, respectively). The change in sperm motility after processing was significantly fewer in the non-pregnant cycles, both when the comparison was conducted by subtraction (post-pre) and division (post/pre). These relationships remained significant after adjusting for the female partner's age, anti-Müllerian hormone level, and number of pre-ovulatory follicles. According to a receiver operating characteristic curve analysis, an initial sperm motility of ≥72.5% was the optimal threshold value for predicting live birth after IUI. Conclusion: Initial sperm motility, rather than the motility of processed sperm or the degree of change after preparation, predicted live birth after IUI procedures.

• Clinical and Experimental Reproductive Medicine
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• v.47 no.2
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• pp.135-139
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• 2020

Objective: In the present study, we aimed to retrospectively evaluate the cumulative live birth rate (LBR) after up to three consecutive embryo transfer (ET) cycles, either fresh or frozen, in women with expected poor ovarian response (ePOR). Methods: We selected 115 women who entered the first in vitro fertilization (IVF) cycle between August 2013 and July 2016. The women were divided into an ePOR group (37 women) and a non-ePOR group (78 women). All women in the ePOR group were ≥ 40 years old or had serum anti-Müllerian hormone levels of less than 1.1 ng/mL at the time of the first IVF cycle. Live birth outcomes were monitored until December 2017. The cumulative LBR (with both conservative and optimistic estimates) was calculated according to the serial number of ET cycles. Results: After up to three ET cycles, the overall cumulative LBR was significantly lower in the ePOR group than in the non-ePOR group (conservative estimate, 10.8% vs. 44.9%, respectively; optimistic estimate, 14.7% vs. 56.1%, respectively; log-rank test, p= 0.003). Conclusion: Women with ePOR exhibited a lower cumulative LBR than women in the non-ePOR group, and this information should be provided to ePOR women during counseling before starting IVF.

• Journal of the Korean housing association
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• v.12 no.2
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• pp.161-169
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• 2001

This study has been performed to analyze association between general housing status and demographic characteristics such as family extension period, total fertility within a family, male birth rates, and birth order among the elderly in Korea. In this study, 183 subjects aged late 60s to 70s were interviewed for their childbearing history under legal marriage and current housing status such as tenure, residence(urban vs rural), and household composition. In this study , average term from the first to the last birth is 11.88 years, and total number of live births is 4.51. The average rate of male firths among live births within a family is 0.532, which is close to data of Korean statistical office in 1995. There were some association of housing status and the fertility; those living in rented units have longer family extension period and rural elderly have higher rate of male children. in addition, there is a significant impact of birth order on tenure. Majority of the first-born subjects were home owners by virtue of bequeath eligibility, and the rate of home owners was 50% higher than the second-born group. Overall in this study, it is recommended that when planning elderly living facilities, service policies be differentiated by both housing & fertility characteristics.

• Journal of Preventive Medicine and Public Health
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• v.23 no.1 s.29
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• pp.87-97
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• 1990

We followed up all the infants born to the married women under 50 years of age residing in Gunwee county, Kyungpook Province, between 1 April 1985 and 31 March 1987, and those born to the married women under 50 years residing in Hapchun County, Kyungnam Province, between 1 March 1987 and 28 February 1988, to their first birthday. Likewise, we followed up the infants born to the women who visited the MCH Center of South District Health Center in Taegu City for delivery between 1 April 1985 and 31 March 1987 to the 27th day after birth and obtained the infant mortality rate and the neonatal mortality rate, respectively. There were 17 infant deaths among 1,359 live births in Gunwee and Hapchun Counties and the infant mortality rate was 12.5 per 1,000 live births. Out of 17 infant deaths, 82.4 percent were neontal death and 17.6 percent were postnonatal deaths. Out of the 6,001 live births born to the women visited the MCH Center, 4,834 infants (80.6%) were followed up to the 27th day after birth. Of these 4,834 infants, 36 infants died before the 28th day after birth and thus the neonatal mortality rate was 7.4 per 1,000 live births. Comparison of the maternal characteristics and the birth weight between infants who were followed up and those who were lost to follow-up showed no significant differences. Assuming that the neonatal and postneounatal mortality ratio had been 6:4, the infant mortality rate for the infants born at the MCH Center would have been 12.3 per 1,000 live births. Taking such findings into consideration as the infant mortality rate observed in Gunwee and Hapchun Counties, the neonatal mortality rate at the MCH Center, the causes of infant deaths, and the low birth weight incidence rate, a conservative estimate of infant mortality rate of Korea would be between 12 and 15 per 1,000 live births in $1985{\sim}1988$.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.300-305
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• 2005

As the current level of birth rate of Korea has dramatically declined, it is obvious that pediatric dentistry will also be affected by this change. This study was performed for the purpose of understanding on the current fertility levels of Korea. The formal data on the number of live births(NLB), crude birth rate(CBR), and total fertility rate(TFR) published annually from the National Statistical Office of Korea from 1992 to 2000 were used as materials for this study. The TFR values from 1990 to 2002 of Korea were compared with those of some western countries with similar history of decreased birth and the CBR values of the metropolitan cities and the capital city Seoul in 2003 were compared domestically, yielding to results as follows. 1. Recent birth rate of Korea was decreased continuously. NLB was about 490,000 CBR was 10.2 and TFR was 1.19. 2. TFR of Korea in 2002 was 1.17, the lowest in the world. 3. There was a large difference in the NLB and CBR between local prefectures and towns of Seoul domestically. Additional population studies and medico-economical studies to exactly predict the demands of pediatric dentistry and proper supplies of manpower in the future was thought urgently required.

• Animal Bioscience
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• v.35 no.9
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• pp.1360-1366
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• 2022

Objective: The present study analyzed the influence of co-transferring embryos with high and low cloning efficiencies produced via somatic cell nuclear transfer (SCNT) on pregnancy outcomes in dogs. Methods: Cloned dogs were produced by SCNT using donor cells derived from a Tibetan Mastiff (TM) and Toy Poodle (TP). The in vivo developmental capacity of cloned embryos was evaluated. The pregnancy and parturition rates were determined following single transfer of 284 fused oocytes into 21 surrogates and co-transfer of 47 fused oocytes into four surrogates. Results: When cloned embryos produced using a single type of donor cell were transferred into surrogates, the pregnancy and live birth rates were significantly higher following transfer of embryos produced using TP donor cells than following transfer of embryos produced using TM donor cells. Next, pregnancy and live birth rates were compared following single and co-transfer of these cloned embryos. The pregnancy and live birth rates were similar upon co-transfer of embryos and single transfer of embryos produced using TP donor cells but were significantly lower upon single transfer of embryos produced using TM donor cells. Furthermore, the parturition rate for TM dogs and the percentage of these dogs that remained alive until weaning was significantly higher upon co-transfer than upon single transfer of embryos. However, there was no difference between the two embryo transfer methods for TP dogs. The mean birth weight of cloned TM dogs was significantly higher upon single transfer than upon co-transfer of embryos. However, the body weight of TM dogs did not significantly differ between the two embryo transfer methods after day 5. Conclusion: For cloned embryos with a lower developmental competence, the parturition rate and percentage of dogs that remain alive until weaning are increased when they are co-transferred with cloned embryos with a greater developmental competence.