Objective:To investigate the effect of the embryo cryopreservation duration on pregnancy and obstetric outcome.Methods:A retrospective cohort study of 2 662 frozen-thawed embyro tranfer (FET) cycles was conducted in the Reproductive Medicine Center, Department of Obstetrics and Gynecology, Tianjin Medical University General Hospital from January 2016 to December 2020. According to embryo cryopreservation duration, the patients were divided into group A (≤1 year, n=2 115), group B (>1 years and ≤3 years, n=319), group C (>3 years and ≤6 years, n=174), and group D (>6 years, n=54). We used the propensity score matching (PSM) to match the baseline data of oocyte retrieval age of the other three groups according to group D at a ratio of 1∶3. Clinical and obstetric outcomes were compared among the four groups. Multiple logistic regression analysis was used to analyze the effect of oocyte retrieval age, embryo transfer age, the duration of embryo cryopreservation, endometrial preparation scheme, endometrial thickness, the number of transferred embryos and the number of high-quality embryos on pregnancy and live birth outcome. Results:1) Before PSM, there were significant differences in the maternal age at oocyte retrieval and embryo transfer and duration of embryo cryopreservation among the four groups(all P<0.001). 2) After PSM, the baseline characteristics of oocyte retrieval age reached a balance among the four groups. There were no statistical differences in the number of embryos transfer, the number of high-quality embryos, the transferred embryo stage, the endometrial regimen among the groups (all P>0.05). The clinical pregnancy rate [37.04% (20/54)] and the live birth rate [33.33% (18/54)] in group D were lower than those in group A [51.57% (82/159), 40.88% (65/159)], group B [50.00% (65/130), 40.77% (53/130)] and group C [49.59% (61/123), 39.02% (48/123)], but the difference was not statistically significant between the four groups ( P=0.310, P=0.781). There were no statistical differences among the four groups in the ratio of male to female newborns, gestational age, birth weight, preterm delivery rate, low birth weight rate, macrosomia rate, birth defects, and premature repture of membranes (all P>0.05). 3) Multiple logistic regression analysis showed that the number of high-quality embryos transferred affected the clinical pregnancy outcome (before PSM, OR=2.614, 95% CI: 2.168-3.151, P<0.001; after PSM, OR=1.984, 95% CI: 1.406-2.800, P<0.001) and live birth (before PSM, OR=2.708, 95% CI: 2.198-3.336, P<0.001; after PSM, OR=2.122, 95% CI: 1.474-3.053, P<0.001). The duration of embryo cryopreservation does not affect the clinical outcome and live birth (all P>0.05). Conclusion:The duration of embryo cryopreservation does not affect the clinical outcome and live birth, but large sample data are still needed to support this conclusion in the future.

Objective:To investigate the effect of the embryo cryopreservation duration on pregnancy and obstetric outcome.Methods:A retrospective cohort study of 2 662 frozen-thawed embyro tranfer (FET) cycles was conducted in the Reproductive Medicine Center, Department of Obstetrics and Gynecology, Tianjin Medical University General Hospital from January 2016 to December 2020. According to embryo cryopreservation duration, the patients were divided into group A (≤1 year, n=2 115), group B (>1 years and ≤3 years, n=319), group C (>3 years and ≤6 years, n=174), and group D (>6 years, n=54). We used the propensity score matching (PSM) to match the baseline data of oocyte retrieval age of the other three groups according to group D at a ratio of 1∶3. Clinical and obstetric outcomes were compared among the four groups. Multiple logistic regression analysis was used to analyze the effect of oocyte retrieval age, embryo transfer age, the duration of embryo cryopreservation, endometrial preparation scheme, endometrial thickness, the number of transferred embryos and the number of high-quality embryos on pregnancy and live birth outcome. Results:1) Before PSM, there were significant differences in the maternal age at oocyte retrieval and embryo transfer and duration of embryo cryopreservation among the four groups(all P<0.001). 2) After PSM, the baseline characteristics of oocyte retrieval age reached a balance among the four groups. There were no statistical differences in the number of embryos transfer, the number of high-quality embryos, the transferred embryo stage, the endometrial regimen among the groups (all P>0.05). The clinical pregnancy rate [37.04% (20/54)] and the live birth rate [33.33% (18/54)] in group D were lower than those in group A [51.57% (82/159), 40.88% (65/159)], group B [50.00% (65/130), 40.77% (53/130)] and group C [49.59% (61/123), 39.02% (48/123)], but the difference was not statistically significant between the four groups ( P=0.310, P=0.781). There were no statistical differences among the four groups in the ratio of male to female newborns, gestational age, birth weight, preterm delivery rate, low birth weight rate, macrosomia rate, birth defects, and premature repture of membranes (all P>0.05). 3) Multiple logistic regression analysis showed that the number of high-quality embryos transferred affected the clinical pregnancy outcome (before PSM, OR=2.614, 95% CI: 2.168-3.151, P<0.001; after PSM, OR=1.984, 95% CI: 1.406-2.800, P<0.001) and live birth (before PSM, OR=2.708, 95% CI: 2.198-3.336, P<0.001; after PSM, OR=2.122, 95% CI: 1.474-3.053, P<0.001). The duration of embryo cryopreservation does not affect the clinical outcome and live birth (all P>0.05). Conclusion:The duration of embryo cryopreservation does not affect the clinical outcome and live birth, but large sample data are still needed to support this conclusion in the future.

OBJECTIVE: To explore the features of genetic differentiation and gene flow of ten minorities in Yunnan province according to nine CODIS short tandem repeat(STR) loci (CSF1PO, FGA, THO1, TPOX, v WA, D3S1358, D5S818, D7S820 and D13S317). METHODS: Heterozygosity and parameters of population differentiation such as F, theta, f and Gst at each locus were calculated. DA genetic distance and fixation index Fst were calculated by Phylip 3.6 and Arlequin 3.0 software, respectively. Phylogenetic trees were constructed by Mega 3.0, and the patterns of gene flow were analyzed by R-matrix model. RESULTS: It showed that average genetic heterogeneity in ten minorities was above 0.7. Significant difference was found for most of the loci in genetic differentiation. Phylogenetic tree analysis showed that the ten minorities were divided into two clusters. The results of the R-matrix analysis showed that the gene flow of Yi and Dai minorities were higher than that of other minorities, while the pattern of gene flow of Dulong minority demonstrated some of the isolation. CONCLUSION Nine STR loci commonly used in forensic identification show a high polymorphism. Heterozygosity can be used for investigating genetic differentiation and gene flow of minority. The ten minorities in Yunnan are independent populations, while the level of differentiation is not high. The relationship in evolution is not far from each other and shows a widely gene flow among the minorities.
Alleles ; China/ethnology* ; Cluster Analysis ; Ethnicity/genetics* ; Gene Flow ; Gene Frequency ; Genetic Structures ; Genetics, Population ; Genotype ; Humans ; Microsatellite Repeats/genetics* ; Models, Genetic ; Pedigree ; Phylogeny ; Polymorphism, Genetic ; Regression Analysis