Safety of embryo cryopreservation: insights from mid-term placental transcriptional changes.

BACKGROUND: In recent years, with benefits from the continuous improvement of clinical technology and the advantage of fertility preservation, the application of embryo cryopreservation has been growing rapidly worldwide. However, amidst this growth, concerns about its safety persist. Numerous studies have highlighted the elevated risk of perinatal complications linked to frozen embryo transfer (FET), such as large for gestational age (LGA) and hypertensive disorders during pregnancy. Thus, it is imperative to explore the potential risk of embryo cryopreservation and its related mechanisms. METHODS: Given the strict ethical constraints on clinical samples, we employed mouse models in this study. Three experimental groups were established: the naturally conceived (NC) group, the fresh embryo transfer (Fresh-ET) group, and the FET group. Blastocyst formation rates and implantation rates were calculated post-embryo cryopreservation. The impact of FET on fetal growth was evaluated upon fetal and placental weight. Placental RNA-seq was conducted, encompassing comprehensive analyses of various comparisons (Fresh-ET vs. NC, FET vs. NC, and FET vs. Fresh-ET). RESULTS: Reduced rates of blastocyst formation and implantation were observed post-embryo cryopreservation. Fresh-ET resulted in a significant decrease in fetal weight compared to NC group, whereas FET reversed this decline. RNA-seq analysis indicated that the majority of the expression changes in FET were inherited from Fresh-ET, and alterations solely attributed to embryo cryopreservation were moderate. Unexpectedly, certain genes that showed alterations in Fresh-ET tended to be restored in FET. Further analysis suggested that this regression may underlie the improvement of fetal growth restriction in FET. The expression of imprinted genes was disrupted in both FET and Fresh-ET groups. CONCLUSION: Based on our experimental data on mouse models, the impact of embryo cryopreservation is less pronounced than other in vitro manipulations in Fresh-ET. However, the impairment of the embryonic developmental potential and the gene alterations in placenta still suggested it to be a risky operation.

Serum androgen profiles in women with premature ovarian insufficiency: a systematic review and meta-analysis.

OBJECTIVE: This meta-analysis aims to investigate serum androgen profiles (testosterone, dehydroepiandrosterone sulfate, androstenedione, and sex hormone-binding globulin) in women with premature ovarian failure and to establish if there is evidence of diminished androgen levels in these women. METHODS: Various Internet sources of PubMed, Cochrane library, and Medline were searched systematically until February, 2018. Out of a pool of 2,461 studies, after applying the inclusion/exclusion criterion, 14, 8, 10, and 9 studies were chosen for testosterone, dehydroepiandrosterone sulfate, androstenedione, and sex hormone-binding globulin, respectively, for this meta-analysis. The effect measure was the standardized mean difference with 95% confidence interval (95% CI) in a random-effects model. RESULTS: The testosterone concentrations in premature ovarian insufficiency were compared with fertile controls: stamdard mean difference (IV, random, 95% CI) -0.73 [-0.99, -0.46], P value < 0.05. The dehydroepiandrosterone sulfate concentrations in premature ovarian insufficiency compared to fertile controls: standard mean difference (IV, random, 95% CI) -0.65 [-0.92, -0.37], P value < 0.05. Androstenedione in premature ovarian insufficiency were compared with fertile controls: standard mean difference (IV, random, 95% CI) -1.09 [-1.71, -0.48], P value < 0.05. Sex hormone-binding globulin levels did not show statistical significance. The dehydroepiandrosterone sulfate levels were reduced in premature ovarian insufficiency cases, but still showed a higher level than in postmenopausal women. CONCLUSIONS: Women with premature ovarian insufficiency are at risk for decreased concentrations of testosterone, dehydroepiandrosterone sulfate, and androstenedione. Dehydroepiandrosterone sulfate levels were more reduced in postmenopausal controls when compared with premature ovarian insufficiency cases.