Objective:To investigate the influencing factors and perinatal outcomes associated with monozygotic twins (MZT) following elective single embryo transfer (eSET) via in vitro fertilization or intracytoplasmic sperm injection and embryo transfer (IVF/ICSI-ET). Methods:A retrospective cohort study was conducted on 12 079 patients who achieved pregnancy after undergoing IVF/ICSI-eSET at Reproductive Health Hospital of the Third Affiliated Hospital of Zhengzhou University between January 2015 and September 2023. Patients were stratified into two groups based on ultrasound findings 30 d post-transfer: singleton pregnancy group and MZT pregnancy group. Finally, 300 MZT and 1 500 single pregnancies, which were randomly matched according to 1∶5 were included by study period. General patients' characteristics, embryo-related factors, and perinatal outcomes were compared between the two groups. A multivariate logistic regression model was employed to identify risk factors for MZT after single embryo transfer, adjusting for potential confounding variables.Results:The incidence of twin pregnancy following single embryo transfer was 2.48% (300/12 079), which was higher than that of naturally conceived monozygotic twin pregnancy. No significant difference was found in baseline characteristics between the two groups (all P>0.05). The blastocyst transfer rate was higher in the MZT pregnancy group [93.3% (280/300)] than in the singleton pregnancy group [88.8% (1 332/1 500), P=0.022]. Multivariate logistic regression analysis also showed that blastocyst transfer was associated with an increased risk of MZT ( OR=0.552, P=0.016, 95% CI: 0.341-0.894). Analysis of blastocyst cycles showed that the risk of MZT was higher when transferring high-quality blastocysts [79.6% (223/280) vs. 67.8% (903/1 332), P<0.001], where as a trophectoderm (TE) grading of C [20.4% (57/280) vs. 32.2% (429/1 332), P<0.001] had a lower risk of MZT. After adjusting for confounding factors, the risk of MZT was found to increase with the transfer of blastocysts with a B-grade inner cell mass (ICM) ( OR=0.601, P=0.001, 95% CI: 0.442-0.819) and A/B grade TE (grade A: OR=2.951, P<0.001, 95% CI: 1.980-4.399; grade B: OR=1.840, P<0.001, 95% CI: 1.315-2.576). The risk of complications during pregnancy [47.7% (143/300) vs. 19.3% (289/1 500), P<0.001], preterm labor [55.1% (140/254) vs. 7.4% (101/1 368), P<0.001], and the risk of stillbirth [3.7% (11/300) vs. 1.5% (22/1 500), P=0.016] were significantly higher in the MZT pregnancy group than in the singleton pregnancy group. Conclusion:Assisted reproductive technology may contribute to the risk of MZT. Transfer of blastocysts, particularly those with loose ICM arrangement and dense TE arrangement, appears to increase the risk of MZT in patients undergoing eSET.

Objective:To investigate the impact of day 3 embryo quality on pregnancy outcomes in frozen-thawed single blastocyst transfer cycles and analyze its value in embryo selection.Methods:A retrospective cohort study was conducted on clinical data from patients undergoing frozen-thawed single blastocyst transfer at the Reproductive Health Hospital of the Third Affiliated Hospital of Zhengzhou University from January 2020 to December 2023. A total of 4 691 cycles of high-quality day 3 embryo (H-D3) group and 2 598 cycles of low-quality day 3 embryo (L-D3) group in the same period were included. Multivariate logistic regression was used to analyze the effects of day 3 embryo quality on clinical pregnancy rate (CPR) and live birth rate (LBR). All the cycles were stratified according to developmental day and quality of blastocyst: 3 920 cycles of high-quality day 5 blastocysts (H-D5), 1 271 cycles of low-quality day 5 blastocysts (L-D5), 834 cycles of H-D6 group and 1 264 cycles of L-D6, the influence of day 3 embryo quality was subsequently analyzed under different conditions.Results:1) Significant differences were observed between H-D3 and L-D3 groups in female age [(31.79±4.42) years vs. (32.28±4.43) years, P<0.001], basal follicle-stimulating hormone levels [6.24 (5.32,7.35) U/L vs. 6.48 (5.42,7.62) U/L, P<0.001], proportion of primary infertility [35.86% (1 682/4 691) vs. 31.99% (831/2 598), P<0.001], proportion of ≥2 prior failed embryo transfer cycles [3.77% (177/4 691) vs. 5.93% (154/2 598), P<0.001], proportion of gonadotropin-releasing hormone agonist/antagonist controlled ovarian hyperstimulation protocol in fresh cycles [93.33% (4 378/4 691) vs. 89.80%(2 333/2 598), P<0.001], embryo cryopreservation duration [3.10 (2.23,7.27) months vs. 3.60 (2.30,15.40) months, P<0.001], proportion of day 5 blastocyst transfers [74.82% (3 510/4 691) vs. 64.70% (1 681/2 598), P<0.001] and proportion of high-quality blastocyst transfers [72.59% (3 405/4 691) vs. 51.92% (1 349/2 598), P<0.001]. No significant differences were found in body mass index, infertility duration, endometrial preparation program or endometrial thickness on transfer day (all P>0.05). 2) Multivariable logistic regression analysis demonstrated that the L-D3 group had significantly lower CPR ( OR=0.837, 95% CI: 0.754-0.929, P<0.001) and LBR ( OR=0.880, 95% CI: 0.794-0.974, P=0.014) compared with the H-D3 group. 3) In H-D5 and L-D5 cycles, L-D3 did not significantly affect CPR ( aOR=0.941, 95% CI: 0.805-1.101, P=0.449; aOR=0.910, 95% CI: 0.724-1.142, P=0.415) or LBR ( aOR=1.034, 95% CI: 0.893-1.196, P=0.657; aOR=0.917, 95% CI: 0.729-1.153, P=0.457). However, in D6-H and D6-L cycles, L-D3 significantly reduced CPR ( aOR=0.732, 95% CI: 0.542-0.987, P=0.041; aOR=0.648, 95% CI: 0.515-0.815, P<0.001) and LBR ( aOR=0.645, 95% CI: 0.479-0.869, P=0.004; aOR=0.670, 95% CI: 0.526-0.854, P=0.001). Conclusion:Day 3 embryo quality significantly impacts both CPR and LBR in frozen-thawed day 6 single blastocyst transfer cycles. This suggests that day 3 embryo quality retains clinical relevance as a selection criterion when prioritizing day 6 blastocysts for transfer.

This study aims to describe the population and regional distribution characteristics of smoking behavior among adult twins in the China Twin Registry (CNTR), as well as the concordance rates for smoking behavior in monozygotic and dizygotic twins, and estimate the heritability. The study population included adult twins in CNTR who had smoking questionnaire data. A random-effects regression model was used to describe the distribution of smoking behavior among different subgroups based on various characteristics. The concordance of smoking behavior between different zygosity groups was calculated, and heritability was estimated. A total of 28 444 twin pairs were included in this study, with an average age of (36.6±12.0) years. Among male twins, 41.2% were current smokers, while only 1.2% of females smoked. Higher smoking rates were observed among male smokers in the 50-59 age group ( z=23.0, P<0.001), northern regions ( z=2.9, P<0.01), rural areas ( z=-5.2, P<0.001), those who were divorced/widowed ( z=3.8, P<0.001), and first-born twins ( z=-4.3, P<0.001), while lower smoking rates were found in those with higher education ( z=-16.1, P<0.001) and unmarried individuals ( z=-16.0, P<0.001). The smoking concordance rate for male monozygotic twins was 69.6%, significantly higher than the 57.3% concordance rate for dizygotic twins ( χ 2=105.0, P<0.05). The heritability of smoking behavior in male twins was estimated at 28.9% (95% CI: 24.3%-33.4%). Stratified analyses showed differences in heritability across regions and age groups: the heritability in northern regions was 32.6% (95% CI: 27.3%-38.0%), higher than the 21.0% (95% CI: 12.4%-29.5%) observed in southern regions; the highest heritability of 35.1% (95% CI: 26.3%-43.9%) was found in the 18-29 age group, with heritability decreasing with age. In conclusion, the smoking rate and influencing factors in the twin population are similar to those in the general population, with unique characteristics, such as higher smoking rates in first-born twins. Genetic factors have a significant impact on smoking behavior.

Objective:To investigate the impact of day 3 embryo quality on pregnancy outcomes in frozen-thawed single blastocyst transfer cycles and analyze its value in embryo selection.Methods:A retrospective cohort study was conducted on clinical data from patients undergoing frozen-thawed single blastocyst transfer at the Reproductive Health Hospital of the Third Affiliated Hospital of Zhengzhou University from January 2020 to December 2023. A total of 4 691 cycles of high-quality day 3 embryo (H-D3) group and 2 598 cycles of low-quality day 3 embryo (L-D3) group in the same period were included. Multivariate logistic regression was used to analyze the effects of day 3 embryo quality on clinical pregnancy rate (CPR) and live birth rate (LBR). All the cycles were stratified according to developmental day and quality of blastocyst: 3 920 cycles of high-quality day 5 blastocysts (H-D5), 1 271 cycles of low-quality day 5 blastocysts (L-D5), 834 cycles of H-D6 group and 1 264 cycles of L-D6, the influence of day 3 embryo quality was subsequently analyzed under different conditions.Results:1) Significant differences were observed between H-D3 and L-D3 groups in female age [(31.79±4.42) years vs. (32.28±4.43) years, P<0.001], basal follicle-stimulating hormone levels [6.24 (5.32,7.35) U/L vs. 6.48 (5.42,7.62) U/L, P<0.001], proportion of primary infertility [35.86% (1 682/4 691) vs. 31.99% (831/2 598), P<0.001], proportion of ≥2 prior failed embryo transfer cycles [3.77% (177/4 691) vs. 5.93% (154/2 598), P<0.001], proportion of gonadotropin-releasing hormone agonist/antagonist controlled ovarian hyperstimulation protocol in fresh cycles [93.33% (4 378/4 691) vs. 89.80%(2 333/2 598), P<0.001], embryo cryopreservation duration [3.10 (2.23,7.27) months vs. 3.60 (2.30,15.40) months, P<0.001], proportion of day 5 blastocyst transfers [74.82% (3 510/4 691) vs. 64.70% (1 681/2 598), P<0.001] and proportion of high-quality blastocyst transfers [72.59% (3 405/4 691) vs. 51.92% (1 349/2 598), P<0.001]. No significant differences were found in body mass index, infertility duration, endometrial preparation program or endometrial thickness on transfer day (all P>0.05). 2) Multivariable logistic regression analysis demonstrated that the L-D3 group had significantly lower CPR ( OR=0.837, 95% CI: 0.754-0.929, P<0.001) and LBR ( OR=0.880, 95% CI: 0.794-0.974, P=0.014) compared with the H-D3 group. 3) In H-D5 and L-D5 cycles, L-D3 did not significantly affect CPR ( aOR=0.941, 95% CI: 0.805-1.101, P=0.449; aOR=0.910, 95% CI: 0.724-1.142, P=0.415) or LBR ( aOR=1.034, 95% CI: 0.893-1.196, P=0.657; aOR=0.917, 95% CI: 0.729-1.153, P=0.457). However, in D6-H and D6-L cycles, L-D3 significantly reduced CPR ( aOR=0.732, 95% CI: 0.542-0.987, P=0.041; aOR=0.648, 95% CI: 0.515-0.815, P<0.001) and LBR ( aOR=0.645, 95% CI: 0.479-0.869, P=0.004; aOR=0.670, 95% CI: 0.526-0.854, P=0.001). Conclusion:Day 3 embryo quality significantly impacts both CPR and LBR in frozen-thawed day 6 single blastocyst transfer cycles. This suggests that day 3 embryo quality retains clinical relevance as a selection criterion when prioritizing day 6 blastocysts for transfer.

Objective:To explore the changes of brain excitation/inhibition balance and gray matter volume (GMV) and their correlations with clinical features in benign childhood epilepsy with centrotemporal spikes (BECTS).Methods:A cross-sectional study was performed; 83 BECTS children enrolled from Department of Diagnostic Radiology, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University from January 2015 to January 2024 were selected as BECTS group. During the same period, 101 age- and gender-matched healthy children were recruited as healthy control group through advertisements in local primary schools. Data of conventional MRI and resting-state functional MRI (rs-fMRI) of the two groups were collected. Whole brain GMV was analyzed by voxel-based morphometry (VBM), and Hurst index was calculated based on time series data of blood oxygen level dependent (BOLD) signal of rs-fMRI. Correlations of GMV and Hurst index with disease duration and onset age in children with BECTS were explored by Pearson correlation analysis.Results:Compared with the healthy control group, the BECTS group had significantly increased GMV and decreased Hurst index in the bilateral Rolandic region ( P<0.05). Pearson correlation analysis showed that in the BECTS group, GMV in bilateral Rolandic region was negatively correlated with onset age ( r=-0.267, P=0.015) and positively correlated with disease course ( r=0.267, P=0.015); Hurst index in bilateral Rolandic region was positively correlated with onset age ( r=0.323, P=0.003) and negatively correlated with disease course ( r=-0.240, P=0.029); Hurst index was negatively correlated with GMV in bilateral Rolandic region ( r=-0.328, P=0.003). Conclusion:BECTS children have excitation/inhibition imbalance in epilepsy-related regions and cortical structural delay, and both of them are related to onset age and disease course.

Objective:To investigate the influencing factors and perinatal outcomes associated with monozygotic twins (MZT) following elective single embryo transfer (eSET) via in vitro fertilization or intracytoplasmic sperm injection and embryo transfer (IVF/ICSI-ET). Methods:A retrospective cohort study was conducted on 12 079 patients who achieved pregnancy after undergoing IVF/ICSI-eSET at Reproductive Health Hospital of the Third Affiliated Hospital of Zhengzhou University between January 2015 and September 2023. Patients were stratified into two groups based on ultrasound findings 30 d post-transfer: singleton pregnancy group and MZT pregnancy group. Finally, 300 MZT and 1 500 single pregnancies, which were randomly matched according to 1∶5 were included by study period. General patients' characteristics, embryo-related factors, and perinatal outcomes were compared between the two groups. A multivariate logistic regression model was employed to identify risk factors for MZT after single embryo transfer, adjusting for potential confounding variables.Results:The incidence of twin pregnancy following single embryo transfer was 2.48% (300/12 079), which was higher than that of naturally conceived monozygotic twin pregnancy. No significant difference was found in baseline characteristics between the two groups (all P>0.05). The blastocyst transfer rate was higher in the MZT pregnancy group [93.3% (280/300)] than in the singleton pregnancy group [88.8% (1 332/1 500), P=0.022]. Multivariate logistic regression analysis also showed that blastocyst transfer was associated with an increased risk of MZT ( OR=0.552, P=0.016, 95% CI: 0.341-0.894). Analysis of blastocyst cycles showed that the risk of MZT was higher when transferring high-quality blastocysts [79.6% (223/280) vs. 67.8% (903/1 332), P<0.001], where as a trophectoderm (TE) grading of C [20.4% (57/280) vs. 32.2% (429/1 332), P<0.001] had a lower risk of MZT. After adjusting for confounding factors, the risk of MZT was found to increase with the transfer of blastocysts with a B-grade inner cell mass (ICM) ( OR=0.601, P=0.001, 95% CI: 0.442-0.819) and A/B grade TE (grade A: OR=2.951, P<0.001, 95% CI: 1.980-4.399; grade B: OR=1.840, P<0.001, 95% CI: 1.315-2.576). The risk of complications during pregnancy [47.7% (143/300) vs. 19.3% (289/1 500), P<0.001], preterm labor [55.1% (140/254) vs. 7.4% (101/1 368), P<0.001], and the risk of stillbirth [3.7% (11/300) vs. 1.5% (22/1 500), P=0.016] were significantly higher in the MZT pregnancy group than in the singleton pregnancy group. Conclusion:Assisted reproductive technology may contribute to the risk of MZT. Transfer of blastocysts, particularly those with loose ICM arrangement and dense TE arrangement, appears to increase the risk of MZT in patients undergoing eSET.

[This corrects the article DOI: 10.1016/j.apsb.2019.01.013.].

This study aims to describe the population and regional distribution characteristics of smoking behavior among adult twins in the China Twin Registry (CNTR), as well as the concordance rates for smoking behavior in monozygotic and dizygotic twins, and estimate the heritability. The study population included adult twins in CNTR who had smoking questionnaire data. A random-effects regression model was used to describe the distribution of smoking behavior among different subgroups based on various characteristics. The concordance of smoking behavior between different zygosity groups was calculated, and heritability was estimated. A total of 28 444 twin pairs were included in this study, with an average age of (36.6±12.0) years. Among male twins, 41.2% were current smokers, while only 1.2% of females smoked. Higher smoking rates were observed among male smokers in the 50-59 age group ( z=23.0, P<0.001), northern regions ( z=2.9, P<0.01), rural areas ( z=-5.2, P<0.001), those who were divorced/widowed ( z=3.8, P<0.001), and first-born twins ( z=-4.3, P<0.001), while lower smoking rates were found in those with higher education ( z=-16.1, P<0.001) and unmarried individuals ( z=-16.0, P<0.001). The smoking concordance rate for male monozygotic twins was 69.6%, significantly higher than the 57.3% concordance rate for dizygotic twins ( χ 2=105.0, P<0.05). The heritability of smoking behavior in male twins was estimated at 28.9% (95% CI: 24.3%-33.4%). Stratified analyses showed differences in heritability across regions and age groups: the heritability in northern regions was 32.6% (95% CI: 27.3%-38.0%), higher than the 21.0% (95% CI: 12.4%-29.5%) observed in southern regions; the highest heritability of 35.1% (95% CI: 26.3%-43.9%) was found in the 18-29 age group, with heritability decreasing with age. In conclusion, the smoking rate and influencing factors in the twin population are similar to those in the general population, with unique characteristics, such as higher smoking rates in first-born twins. Genetic factors have a significant impact on smoking behavior.

Objective:To explore the changes of brain excitation/inhibition balance and gray matter volume (GMV) and their correlations with clinical features in benign childhood epilepsy with centrotemporal spikes (BECTS).Methods:A cross-sectional study was performed; 83 BECTS children enrolled from Department of Diagnostic Radiology, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University from January 2015 to January 2024 were selected as BECTS group. During the same period, 101 age- and gender-matched healthy children were recruited as healthy control group through advertisements in local primary schools. Data of conventional MRI and resting-state functional MRI (rs-fMRI) of the two groups were collected. Whole brain GMV was analyzed by voxel-based morphometry (VBM), and Hurst index was calculated based on time series data of blood oxygen level dependent (BOLD) signal of rs-fMRI. Correlations of GMV and Hurst index with disease duration and onset age in children with BECTS were explored by Pearson correlation analysis.Results:Compared with the healthy control group, the BECTS group had significantly increased GMV and decreased Hurst index in the bilateral Rolandic region ( P<0.05). Pearson correlation analysis showed that in the BECTS group, GMV in bilateral Rolandic region was negatively correlated with onset age ( r=-0.267, P=0.015) and positively correlated with disease course ( r=0.267, P=0.015); Hurst index in bilateral Rolandic region was positively correlated with onset age ( r=0.323, P=0.003) and negatively correlated with disease course ( r=-0.240, P=0.029); Hurst index was negatively correlated with GMV in bilateral Rolandic region ( r=-0.328, P=0.003). Conclusion:BECTS children have excitation/inhibition imbalance in epilepsy-related regions and cortical structural delay, and both of them are related to onset age and disease course.

【Objective】 To analyze the genetic variation characteristics and clinical phenotypes of a family with primary microcephaly (MCPH) caused by RTTN gene variation, and to provide reference for genetic counseling and prenatal diagnosis. 【Methods】 Clinical data of the three patients (including 2 fetuses and 2-year-old proband,and one fetus with clinical diagnosis) and their parents were collected and analyzed. Two of the children and their parents were tested by trio whole exome sequencing (trio-WES), sanger sequencing validation sites, and the hazard of their compound heterozygous variants was predicted. Literature review was conducted through domestic and international databases to collect reported RTTN gene mutation cases. 【Results】 Three patients in this family had anomalies of the septum pellucidum, hypoplasia of the corpus callosum and other brain malformations during fetal period. The proband (G2) and fetus (G3) showed intrauterine growth retardation and MCPH in late pregnancy; besides, G2 was born with global developmental delay. Trio-WES detected a c.2101(exon16)C>T(p.Arg701Ter,1526) nonsense and a c.2863(exon22)G>A(p.Glu955Lys)missense in the RTTN gene of G2 and G3, which were inherited from their father and mother, forming a compound heterozygous variant. According to the American College of Medical Genetics and Genomics (ACMG) variant classification guidelines, two variants were likely to be pathogenic (LP) and uncertain significance (VUS). Among them, c.2863(exon22)G>A was a newly discovered missense, which was predicted by the software to be harmful to the gene product. 【Conclusions】 Complex heterozygous variations of RTTN gene (c.2101C>T and c.2863G>A) are the genetic cause of MCPH in this family. This report has enriched the variation spectrum of RTTN gene, provided guidance for prenatal diagnosis and reproduction of this family, as well as material and reference for further understanding of the diseases caused by this gene mutation.