No advantage of single day 6 good-quality blastocyst transfer versus single day 5 poor-quality blastocyst transfer in frozen-thawed cycles stratified by age: a retrospective study

Abstract

Background Blastocyst developmental speed, morphological grading and patient age are associated with pregnancy outcomes of frozen-thawed cycles. This study aimed to compare the clinical and neonatal outcomes between poor-quality D5 blastocysts and good-quality D6 blastocysts stratified by patient age. Methods A total of 1,623 cycles were divided into two groups: group A (n = 723) received one D5 poor-quality blastocyst; group B (n = 900) received one D6 good-quality blastocyst. Pregnancy and neonatal outcomes were compared among the four groups stratified by 35 years of age. Results When patients were in the same age group, there was no significant difference in terms of age, body mass index, infertility duration, infertility type, fertilization method, proportion of endometrial preparation protocols, and endometrial thickness between D5 poor-quality and D6 high-quality blastocysts groups. Live birth rate of D5 poor-quality blastocysts was higher than that of D6 high-quality blastocysts for patients aged < 35 years (35.48% vs. 31.13%, p > 0.05), but there was no statistical difference. The same trend was showed for patients aged ≥ 35 years (29.09% vs. 21.28%, p > 0.05). Moreover, when patients were in the same age category, there was no significant difference in terms of gestational age, birth weight, birth height, and rates of preterm birth, low birth weight, and very low birth weight between groups A and B. Conclusions The preferential selection of poor-quality D5 blastocysts for transfer compared to high-quality D6 blastocysts is recommended, especially for advanced age patients. Single good-quality D6 blastocyst transfer can be considered for the acceptable live birth rate.

Effect of development speed and quality of blastocyst on singleton birthweight in single frozen-thawed blastocyst transfer cycles

“…This is similar to the conclusions of some studies. For example, a study revealed that the gestational age and birthweight of low-quality blastocysts transferred on D5 did not significantly differ from those of high-quality blastocysts transferred on D6 ( 28 ). A large retrospective study, including data on 7,469 females with singleton births, revealed that both groups had similar outcomes after transferring a high- or non-high-quality blastocyst ( 14 ).…”

“…The results are similar to those of several recent studies (19, 27, 28). He et al (28) divided their study patients into two groups based on age (< 35 years and ≥ 35 years). They observed that the neonatal outcomes of the group with transferred D5 non-excellent embryos were similar to those of the group with transferred D6 excellent embryos in both age groups.…”