Tarih:Feb 06, 2017 Yazar:Ender Yalcinkaya Kalyan
This is the question that I hear from our patients in recent times. Is fresh embryo transfer or frozen embryo transfer better? Today, clinical pregnancy rates of fresh and frozen embryo transfers are comparable. Depending on the condition of the patients, even frozen embryo transfers may give better results. Then, what are these conditions, and can frozen embryo transfer be applied to everyone? I would like to write about this topic.
Firstly, I need to say that every patient can not be suitable for frozen embryo transfer. For freezing embryos, it is important to have good quality (grade 1 and 2) embryos. Survival rates of poor quality embryos are bad; however, survival rates of good quality embryos are around 97-98%. Nearly 10 years ago, embryologists were behaving more timid for embryo cryopreservation since survival rates were much more lower compared to now. However, embryos survive at a ratio of almost 100% with the improvements in cryopreservation techniques ( especially with the improvement in rapid freezing method called vitrification) after thawing today; and this enables us to recommend embryo freezing to our patients comfortably. The best part of frozen embryo transfers is to provide a controlled thickening of the endometrium with using less hormones. Thus, pregnancy rates of embryos that survive after thawing may be higher.
Then, we can say that the condition of the patients should be suitable and the embryo quality should be appropriate for freezing in order to plan a frozen embryo transfer. As the condition of the patients, I mean some special cases. They are as follows: emergence of OHSS (ovarian hyperstimulation syndrome) due to production of higher number of follicles with the use of high doses of gonadotrophins, presence of a history of failed fresh embryo transfers, insufficient thickening or overthickening of endometrial tissue or freezing of embryos for genetic analyses.
In a previous report in Australia and New Zealand, it was stated that a 5% increase has been observed in the success rates of frozen embryo transfers within the last 5 years. This situation was explained by the improvements in the freezing techniques during these years. While the same increase was not observed in fresh embryo transfers, success rates of frozen-thawed embryo transfers showed a significant increase. This is very similar also in our country.
I, as a clinical embryologist, can say that I like frozen embryo transfers very much but when it is used for the right patient group in case of right indication:)
Please contact me if you have further questions about this topic. Take care.