Background Along with progress in embryo cryopreservation, especially the vitrification, freeze all strategy has become more acceptable than ever. Some studies have found comparable or higher live birth rate with frozen embryo transfer (FET) than with fresh embryo transfer(ET)in gonadotropin releasing hormone antagonist (GnRH-ant) protocol. However from our literature research, there have been no reports about live birth rate comparison between fresh ET and FET with gonadotropin releasing hormone agonist (GnRH-a) long protocol. The aim of this study is to retrospectively investigate whether patients benefit from freeze all strategy in GnRH-a protocol using real-world data. Methods This is a retrospective cohort study, in which women undergoing fresh ET or FET with GnRH-a long protocol at Chongqing Reproductive and Genetics Institute from January 2016 to December 2018 were evaluated. The primary outcome was live birth rate. The secondary outcomes were implantation rate, clinical pregnancy rate, pregnancy loss and ectopic pregnancy rate. Results A total of 7,814 patients met inclusion criteria, implementing 5,216 fresh ET cycles and 2,598 FET cycles, respectively. The demographic characteristics of the patients were significantly different between fresh ET and FET groups, except BMI. After controlling for a broad range of potential confounders including age, infertility duration, BMI, AMH, number of oocytes retrieved and of available embryos, multivariate logistic regression analysis demonstrated that there was no significant difference in clinical pregnancy rate, ectopic pregnancy rate and pregnancy loss rate between two groups (all P > 0.05). However, the implantation rate and live birth rate in fresh ET group were significantly higher than FET group (P < 0.001 and P = 0.012, respectively). Conclusions Under GnRH-a long protocol, compared to FET, fresh ET was associated with higher implantation rate and live birth rate in infertile patients that underwent in vitro fertilization (IVF). The freeze all strategy should be individualized and made with caution especially with GnRH-a long protocol.

ObjectiveThis study aims to identify the risk factors associated with short stature in children born small for gestational age (SGA) at full-term.MethodsThis was a retrospective study. The subjects were full-term SGA infants who were followed up until the age of 2 years. The risk factors for short stature were identified with univariate and multivariate analyses.ResultsOf 456 full-term SGA children enrolled in this study, 28 cases had short stature at 2 years of age. A significant decrease in placental perfusion was found in the short children group with intravoxel incoherent motion (IVIM) technology, which was an advanced bi-exponential diffusion-weighted imaging (DWI) model of magnetic resonance imaging (MRI) (p = 0.012). Compared to non-short children born SGA at full-term, the short children group underwent an incomplete catch-up growth. Mothers who suffered from systemic lupus erythematosus were more likely to have a short child born SGA (p = 0.023). The morbidity of giant placental chorioangioma was higher in the short children group. The pulsatility index (PI), resistivity index (RI), and systolic-diastolic (S/D) ratio of umbilical artery were higher in the short children group than in the non-short control group (p = 0.042, 0.041, and 0.043). Multivariate analysis demonstrated that decrease of perfusion fraction (fp) in IVIM of placental MRI, chromosomal abnormalities, short parental height, and absence of catch-up growth were associated with a higher risk of short stature in children born SGA at full-term.ConclusionRisk factors for short stature in full-term SGA children at 2 years of age included a decrease of perfusion fraction fp in IVIM of placental MRI, chromosomal abnormalities, and short parental height.

Background: Along with progress in embryo cryopreservation, especially in vitrification has made freeze all strategy more acceptable. Some studies found comparable or higher live birth rate with frozen embryo transfer (FET) than with fresh embryo transfer（ET）in gonadotropin releasing hormone antagonist (GnRH-ant) protocol. But there were no reports about live birth rate differences between fresh ET and FET with gonadotropin releasing hormone agonist (GnRH-a) long protocol. The aim of this study is to analyze whether patients benefit from freeze all strategy in GnRH-a protocol from real-world data.Methods: This is a retrospective cohort study, in which women undergoing fresh ET or FET with GnRH-a long protocol at Chongqing Reproductive and Genetics Institute from January 2016 to December 2018 were evaluated. The primary outcome was live birth rate. The secondary outcomes were implantation rate, clinical pregnancy rate, pregnancy loss and ectopic pregnancy rate.Results: A total of 7,814 patients met inclusion criteria, implementing 5,216 fresh ET cycles and 2,598 FET cycles, respectively. The demographic characteristics of the patients were significantly different between two groups, except BMI. After controlling for a broad range of potential confounders (including age, infertility duration, BMI, AMH, no. of oocytes retrieved and no. of available embryos), multivariate logistic regression analysis demonstrated that there was no significant difference in terms of clinical pregnancy rate, ectopic pregnancy rate and pregnancy loss rate between two groups (all P>0.05). However, the implantation rate and live birth rate of fresh ET group were significantly higher than FET group (P<0.001 and P=0.012, respectively).Conclusion: Compared to FET, fresh ET following GnRH-a long protocol could lead to higher implantation rate and live birth rate in infertile patients underwent in vitro fertilization (IVF). The freeze all strategy should be individualized and made with caution especially with GnRH-a long protocol.