Early-cleavage versus blastocyst stage embryo transfer: a prospective comparative study.

Objective To evaluate whether or not embryo transfer day has an effect on the rates of clinical pregnancy (CPR) and live birth (LBR) in in vitro fertilization-intracytoplasmic sperm injection (IVF-ICSI) treatment. Material and Methods A total of 757 patients who had undergone IVF-ICSI treatment between 2012 and 2017 were included in this study. The participants were stratified according to embryo transfer day as Group 1 (day 2 transfer; n= 43), Group 2 (day 3 transfer; n=633), and Group 3 (day 5 (blastocyst) transfer; n=81). Basal parameters and IVF-ICSI outcomes were compared between the groups. Results Groups 1 and 2 patients were older, had a higher BMI, worse responder rate, lower antral follicle count, lower peak E2 levels, and less endometrial thickness, and required an increased total gonadotropin dose than the other transfer day groups. In addition, the number of oocytes and MII oocytes, fertilization rate, and 2 PN were statistically different between the groups and the CPR (19.5% vs 36.9% vs 39.0%, respectively) and LBR (14.6% vs 30.4% vs 35.1%, respectively) were lower in group 1 than groups 2 and 3 (p<0.05). The grade I embryos were significantly higher in groups 1 and 2 with clinical pregnancy positive (OR=4.444; 95% CI 0.876-22.536; p=0.001 and OR=1.756; 95% CI 1.234-2.500; p<0.001) and live birth (OR=5.021; 95% CI 0.787-31.768; p=0.001 and OR=1.676; 95% CI 1.154-2.433; p=0.007). Conclusions The data suggest that an earlier embryo transfer day has a negative effect on the clinical pregnancy rate. Older primary infertile women should not postpone their desire to have a baby because they are poor responders, and it should be explained that the chances of successful treatment are lower.