Differentiated approach to the embryological stage in frozenthawed embryo transfer

Objective. To evaluate the effectiveness of additional embryological techniques in frozen-thawed embryo transfer programs. Materials and methods. The study included 288 couples treated for infertility using assisted reproductive technologies (ART) with frozen-thawed embryo transfer. The couples were stratified into two groups depending on the onset of pregnancy: group 1 consisted of couples who achieved pregnancy (pregnancy +, n=92), group 2 included the couples who did not achieve pregnancy (pregnancy -, n=196). The influence of the embryological stage on the effectiveness of ART programs was evaluated. Results. The use of pronase hatching increases the ART effectiveness in patients under 33 years by 3.3 times and the use of pronase hatching reduces the pregnancy rate in patients aged 34 years and older, while laser hatching increases the pregnancy rate by 4.8 times. The use of a culture medium enriched with hyaluronic acid (Embryoglue) increases the pregnancy rate in patients aged 38 years and older and in patients with previous history of three or more ineffective embryo transfer cycles. Prolonged embryo cultivation after thawing and before embryo transfer to the uterine cavity does not influence the effectiveness of frozen-thawed embryo transfer. Conclusion. None of the additional embryological techniques has shown its effectiveness in its regular use. Further research should be aimed at identifying groups of patients who need to be recommended certain modern embryological techniques, as well as their combinations.

assisted reproductive technologies, embryos, hatching, pregnancy, embryo thawing, frozen embryos, frozen-thawed embryo transfer