[Effect of preimplantation genetic testing for aneuploidies on pregnancy outcome in patients with unexplained recurrent spontaneous abortion]

Objective: To investigate the effect of preimplantation genetic testing for aneuploidies (PGT-A) on pregnancy outcome and perinatal outcome of single live birth in patients with unexplained recurrent spontaneous abortion (URSA). Methods: The clinical data of 351 cycles of the first transfer of a blastocyst through whole embryo freezing in the Reproductive Center of the Third Affiliated Hospital of Zhengzhou University from 2019 to 2021 were retrospectively analyzed. According to whether PGT-A was performed before the transfer, the patients were divided into two groups: the PGT-A group (160 cycles) and the control group (191 cycles) were treated with in vitro fertilization/intracytoplasmic sperm microinjection (IVF/ICSI). To adjust for confounding factors, propensity score matching (PSM) was carried out in a 1∶1 ratio between the two groups of patients. After matching, 98 patients in the PGT-A group and 98 patients in the control group were compared for pregnancy outcome and perinatal outcome of singleton live births. Results: Before PSM, the female age in the PGT-A group was (33.6±4.0) years, lower than that in the control group (34.5±4.5) years (P=0.049). Male age in the PGT-A group was (33.6±4.1) years, lower than that in the control group (35.3±5.1) years (P<0.001). There were statistically significant differences between the two groups in infertility factors, female body mass index (BMI), years of infertility, number of spontaneous abortions, basal follicle stimulating hormone (FSH), endometrial thickness on the day of transfer and the percentage of high-quality blastocysts (all P values<0.05); After PSM, there was a statistically significant difference in fertilization methods and infertility factors between the two groups (P<0.05), while other differences were not statistically significant (all P values>0.05); There were statistically significant differences between the two groups in implant rate [63.3% (62 cycles) vs. 49.0% (48 cycles), P=0.044], clinical pregnancy rate [63.3% (62 cycles) vs. 49.0% (48 cycles), P=0.044], and live birth rate [42.9% (42 cycles) vs. 28.6% (28 cycles), P=0.037]. There was no statistically significant difference in perinatal outcomes between the PGT-A group and the control group in obtaining single birth live births (P>0.05). Conclusion: Compared with conventional IVF/ICSI assisted pregnancy, PGT-A assisted pregnancy significantly improves implantation rate, clinical pregnancy rate, and live birth rate in URSA patients. PGT-A improves the pregnancy outcomes in URSA patients but not perinatal outcomes in patients with singleton live births.

[The effects of high risk of ovarian hyperstimulation syndrome and duration of embryo cryopreservation on perinatal outcomes of single live births in the first frozen embryo transfer cycle after whole embryo cryopreservation]

Objective: To investigate the effects of high risk of ovarian hyperstimulation syndrome (OHSS) and duration of embryo cryopreservation on perinatal outcomes of the first frozen-thawed cycle after whole embryo cryopreservation. Methods: The clinical data of 1 804 patients who underwent the first frozen-thawed cycle after whole embryo cryopreservation and achieved singleton live births in the Reproductive Center of the Third Affiliated Hospital of Zhengzhou University from January 2016 to June 2021 were retrospectively analyzed. According to whether there was high risk of OHSS in the oocyte retrieval cycle, the patients were divided into high-risk group (n=790) and non-high-risk group (n=1 014). The baseline data and perinatal outcomes were compared between the two groups. Multivariate linear regression was applied to analyze the relative factors affecting neonatal weight. And the high-risk group was divided into three subgroups according to different cryopreservation time: the embryos of 96 cycles with a cryopreservation time less than 60 days were defined as group A; the embryos of 587 cycles with a cryopreservation time around 60 to 120 days were defined as group B; the embryos of 107 cycles with a cryopreservation time more than 120 days were defined as group C. The perinatal outcomes were compared among the three groups. The measurement data in this study were represented by［M（Q₁，Q₃）］. Results: The female age in the high-risk group was 30.0 (27.0, 32.0) years old, which was lower than that in the non-high-risk group 31.0 (29.0, 34.0) (P<0.001). The male age in high-risk group was 30.0 (28.0, 33.0), lower than that in non-high-risk group 32.0 (29.0, 35.0) (P<0.001). The birth weight of high-risk group [3 500.0 (3 200.0,3 800.0) g] was higher than that of control group [3 400.0 (3 150.0,3 800.0) g](P=0.045). Multivariate linear regression analysis showed that female BMI was correlated with neonatal weight, β (95%CI) was 15.37(8.33, 22.41) (P<0.001), and the high risk of OHSS was not correlated with neonatal weight, β (95%CI) was 19.40 (-38.07, 76.87) (P=0.508). There was significant difference in the incidence of low birth weight and very low birth weight among groups A, B and C (all P values<0.05), and the incidence of low birth weight and very low birth weight in group C was higher than that in group B (all P values<0.017). Conclusions: The risk of adverse perinatal outcomes in high-risk OHSS patients who underwent the first frozen-thawed cycle after whole embryo cryopreservation was not increased. However, prolonged cryopreservation of embryos may lead to increased risk of low birth weight and very low birth weight.