Prognostic factors for patients undergoing vitrified-warmed human embryo transfer cycles: a retrospective cohort study

Patient- and cycle-specific factors affecting the outcome of frozen-thawed embryo transfers

PURPOSE

This study attempted at identifying the main parameters influencing the outcome of frozen embryo transfers.

METHODS

This is a single-center retrospective cohort study of 830 frozen-embryo-transfer cycles performed at a German university hospital from January 2012 to December 2016. Main outcome parameters were the clinical pregnancy and live birth rate. Twelve patient- and cycle-dependent factors were analyzed in terms of their influence on the outcome of frozen embryo transfers. Multivariate logistic regression analysis was used for the modelling of the dependency of the different parameters on outcomes.

RESULTS

The clinical pregnancy rate in our study was 25.5%, the live birth rate was 16.1% with an average maternal age of 34.2 years at the time of the oocyte retrieval. In the univariate analysis age, number of transferred embryos, blastocyst versus cleavage stage transfer, embryo quality and mode of endometrial preparation affected the birth rate significantly. The birth rate after artificial endometrial preparation was significantly lower than the birth rate after transfers in modified natural cycles (12.8 versus 20.6% with p = 0.031). The multivariate logistic regression analysis showed a significant independent influence of age, number of transferred embryos, culture duration and mode of endometrial preparation on the frozen embryo transfer success rates. Body mass index, nicotine abuse, a history of PCO syndrome or endometriosis and the co-transfer of a second poor-quality embryo to a good-quality embryo appeared to be irrelevant for the outcome in our collective.

CONCLUSION

Age, number of transferred embryos, embryo culture duration and the mode of endometrial preparation are independent predictive factors of frozen embryo transfer outcomes.

Concentrations of homocysteine in follicular fluid and embryo quality and oocyte maturity in infertile women: a prospective cohort

Homocysteine is one of the components of follicular fluid (FF), so that any disruptions in its concentration may affect oocyte development. The aim of this study was to determine the relationship between FF homocysteine concentration and embryo quality, oocyte maturity, and pregnancy rate. Oocytes and embryos of 44 infertile women were categorised into different groups based on their maturity and quality, respectively. FF homocysteine levels, oocyte maturity, embryo quality, and pregnancy status were measured. A significant association was observed between the levels of FF homocysteine ​and oocyte maturation rate (p = .00). The concentration of FF homocysteine was higher than 9.8 µm/L in women with oocyte maturation < 80%. Most of the good quality embryos belonged to homocysteine levels < 9.8 µm/L. Decreased FF homocysteine concentrations can significantly improve the oocyte maturation rate and embryo quality. Aging may be an indirect factor contributing to decreased embryo quality and oocyte maturation through increasing FF homocysteine levels.IMPACT STATEMENTWhat is already known on this subject? It has been demonstrated that homocysteine is one of the components of follicular fluid (FF), but no information is available about the link between its concentration in FF and oocyte development.What do the results of this study add? The data indicated that decreased FF homocysteine concentrations at a younger age may remarkably improve the oocyte maturity and embryo quality of infertile patients undergoing assisted reproductive treatment (ART).What are the implications of these findings for clinical practice and/or further research? Based on the findings and considering the ease of measuring serum homocysteine and its direct correlation with FF homocysteine, homocysteine level measurement is recommended in patients who are candidates for infertility treatment in order to estimate oocyte maturation rate, embryo quality, and ART outcomes. Future studies are suggested to investigate patients with PCOS, endometriosis, and male factor infertility.