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 analyze the reproductive outcomes of the subsequent embryo transfer (ET) cycles in women with repeated implantation failure (RIF) after the management of uterine cavity abnormalities.Methods:This was a retrospective case-control study. The clinical data of 89 patients with repeated implantation failure who underwent hysteroscopy at Reproductive Medicine Center of the Department of Obstetrics and Gynecology, Tianjin Medical University General Hospital from January 1, 2017 to March 31, 2021 were analyzed. The patients were assigned to a normal uterine cavity (UC) group ( n=38) and an abnormal UC group ( n=51) according to hysteroscopic examination and endometrial biopsy results. Women in the abnormal UC group received relevant treatments, and all patients received the embryo transfer again. The reproductive outcomes were compared between the two groups in the subsequent ET cycles. Results:The prevalence of uterine abnormalities was 57.30% (51/89) in women with RIF. Chronic endometritis accounted for the highest incidence 39.33% (35/89). Among 38 women in normal UC group, 16 women got clinical pregnancy in the subsequent ET cycles, and 24 women in 51 got clinical pregnancy in the abnormal UC group. There were no differences in the implantation rate, the clinical pregnancy rate, and the ectopic pregnancy rate between the two groups (all P>0.05). The early abortion rate was significantly higher in the normal UC group [37.50% (6/16)] than in the abnormal UC group [8.33% (2/24), P=0.042]. Conclusion:The uterine abnormalities mainly occurred in women with primary infertility. The clinical pregnancy rate of women after correction of uterine abnormalities was similar to those women with normal UC. Hysteroscopy was advised to performed routinely to evaluate the uterine environment in women with RIF.

Objective:To analyze the reproductive outcomes of the subsequent embryo transfer (ET) cycles in women with repeated implantation failure (RIF) after the management of uterine cavity abnormalities.Methods:This was a retrospective case-control study. The clinical data of 89 patients with repeated implantation failure who underwent hysteroscopy at Reproductive Medicine Center of the Department of Obstetrics and Gynecology, Tianjin Medical University General Hospital from January 1, 2017 to March 31, 2021 were analyzed. The patients were assigned to a normal uterine cavity (UC) group ( n=38) and an abnormal UC group ( n=51) according to hysteroscopic examination and endometrial biopsy results. Women in the abnormal UC group received relevant treatments, and all patients received the embryo transfer again. The reproductive outcomes were compared between the two groups in the subsequent ET cycles. Results:The prevalence of uterine abnormalities was 57.30% (51/89) in women with RIF. Chronic endometritis accounted for the highest incidence 39.33% (35/89). Among 38 women in normal UC group, 16 women got clinical pregnancy in the subsequent ET cycles, and 24 women in 51 got clinical pregnancy in the abnormal UC group. There were no differences in the implantation rate, the clinical pregnancy rate, and the ectopic pregnancy rate between the two groups (all P>0.05). The early abortion rate was significantly higher in the normal UC group [37.50% (6/16)] than in the abnormal UC group [8.33% (2/24), P=0.042]. Conclusion:The uterine abnormalities mainly occurred in women with primary infertility. The clinical pregnancy rate of women after correction of uterine abnormalities was similar to those women with normal UC. Hysteroscopy was advised to performed routinely to evaluate the uterine environment in women with RIF.