Are there associations between clinical and embryological factors with pregnancy loss following transfer of a single euploid embryo?

First trimester pregnancy losses are commonly attributed to chromosomal abnormalities. The causes of pregnancy loss following transfer of a euploid embryo are not fully elucidated. The aim of this study was to evaluate clinical and embryological parameters for pregnancy failure following the transfer of a single euploid embryo. Pregnancy outcomes of single euploid embryo transfers from a single centre between January 2017 and March 2020 were retrospectively evaluated. Several clinical and embryological parameters were evaluated in consideration to pregnancy outcomes; total pregnancy loss and live birth. Endometrial preparation type, number of previous frozen embryo transfer cycles, history of recurrent pregnancy loss, higher body mass index, presence of endometriosis and/or adenomyosis and embryo quality were found to be significantly different between two groups. Morphokinetic parameter analysis of 523 euploid embryos using time-lapse imaging did not show any statistical differences between the two groups, however a significantly higher rate of uneven blastomeres in the cleavage stage was observed in the total preganncy loss group. Evaluation of clinical and embryological data can reveal possible factors associated with pregnancy loss that can facilitate improved patient consultation. Feasible interventions can potentially increase the chance of achieving a live birth.

Factors influencing the number of mature oocytes and cryopreservable blastocysts in hyperresponder patients triggered with a GnRH analog.

PURPOSE: This study aimed to investigate which patient and cycle characteristics may affect the number of mature oocytes and cryopreservable blastocysts in the GnRH analog trigger cases. METHODS: This was a retrospective cohort study of 2749 GnRHa trigger cycles in patients at risk of OHSS, including a group of PGT patients, between 2011 and 2020 at Istanbul Memorial Hospital, ART and Reproductive Genetics Center. Patient and cycle characteristics were evaluated using the Generalized Linear Mixed Model (GLMM). The number of mature oocytes and the number of cryopreservable blastocysts were evaluated. RESULTS: A one-unit increase in female age, daily gonadotropin dose, E2 level on day 2, and LH level on trigger day significantly decreased the number of mature oocytes retrieved (p < 0.001) and the number of cryopreservable blastocysts as p < 0.001, p < 0.001, p < 0.001, and p = 0.003, respectively. The duration of GnRH antagonist use also decreased the number of mature oocytes retrieved (p < 0.001) but not the number of cryopreservable blastocysts. CONCLUSION: The GLMM used in our study showed that a one-unit increase in female age, daily gonadotropin dose, E2 level on day 2, and LH level on trigger day significantly decreased the number of mature oocytes retrieved and the number of cryopreservable blastocysts.

What to advise to patients with only one good quality blastocyst, PGT-A or not? Outcomes of 2064 cycles.

PURPOSE: To evaluate whether preimplantation genetic testing for aneuploidy (PGT-A) is beneficial for patients who have only one blastocyst available for biopsy or transfer. METHODS: This retrospective study was based on 1126 single blastocyst PGT-A and 938 non-PGT-A cycles, a total of 2064 ART cycles which resulted in a single good quality blastocyst in women between 20 and 45 years old. The PGT-A group had 225 single euploid embryo transfer cycles and the non-PGT-A group had 938 single blastocyst embryo transfer cycles. RESULTS: In the generalized linear mixed model (GLMM), female age and PGT-A variables were found to be significant variables on pregnancy outcomes. In the PGT-A cases, regardless of the effect of other variables, the probabilities of clinical pregnancy and live birth were found to be 3.907 and 3.448 fold higher respectively than in the non-PGT-A cases (p < 0.001). In non PGT-A cases, the probability of a total pregnancy loss was found to be 1.943 fold higher (p = 0.013). CONCLUSION: PGT-A in the presence of a single blastocyst significantly increases clinical pregnancy and live birth rates and decreases total pregnancy losses regardless of age. In addition, aneuploid embryo transfer cancelations prevent ineffective and potentially risky transfers.

Incidence of multiple births in relation to current regulations in Turkey regarding embryo transfer.

BACKGROUND: Before 2010, there were no regulations in Turkey regarding the number of embryos to be transferred in one cycle. In March 2010, regulations restricting this number were implemented by the Turkish Ministry of Health. These specify the transfer of a maximum of one embryo in the first and second cycles and a maximum of two embryos in subsequent cycles in women aged < 35, and a maximum of two embryos in women aged ≥35 in any one cycle. Our study evaluates the effect of these regulations. METHODS: This large retrospective single center study first evaluates the incidence of multiple pregnancies before and after the implementation of the 2010 regulations. Secondly, it compares the clinical outcomes of double blastocyst transfer (DBT) and single blastocyst transfer (SBT) performed in compliance with these regulations from 2014 onwards. RESULTS: After the introduction of the 2010 regulations, the multiple pregnancy rate decreased significantly from 37.9 to 15.7%. The singleton live birth rate increased significantly, whereas multiiple live birth rates significantly decreased (p = < 0.001). When the clinical outcomes of SBT and DBT performed in compliance with regulations from 2014 onwards were evaluated, in patients < 35 years, the multiple pregnancy rate decreased from 47.2% in the DBT group to 1.7% in the SBT group (p = < 0.001). In patients ≥35 years, in the DBT group, the twin birth rate was again high at 28.4%, whereas in the SBT group, it was only 1.8% (p = < 0.001). Importantly, there was no statistically significant difference in clinical pregnancy rates between these two groups. CONCLUSION: Turkish regulations have led to an encouragement of double embryo transfer (DET) as a routine practice, with many patients understanding it as an absolute right to have two embryos transferred. The results of our study suggest that, especially in the light of the success of blastocyst transfer, the Turkish regulations should be amended to limit the use of DET and encourage the use of single embryo transfer except in exceptional cases and particularly in women under 35 years old.