Live Birth after Cleavage-Stage versus Blastocyst-Stage Embryo Transfer in Assisted Reproductive Technology: A Randomised Controlled Study

Abstract

Background: Blastocyst stage transfer appears to improve pregnancy outcomes. The aim of this study is to evaluatethe pregnancy results between fresh cycle blastocyst stage embryo transfer and cleavage stage embryo transfer inpatients who undergo intracytoplasmic sperm injection (ICSI).Materials and Methods: This randomised clinical trial study was conducted at the Infertility Research Centre of MiladHospital in Mashhad, Iran from 2018 to 2020 on 240 infertile women who presented for their first ICSI procedure.These patients were assigned to receive either cleavage embryo transfer (n=112) or blastocyst stage transfer (n=107).Pregnancy outcomes were measured in both groups.Results: There were no differences regarding age, body mass index (BMI), serum follicle-stimulating hormone (FSH),duration of infertility, and aetiology of infertility between the groups (P>0.05). There were more follicles, total oocytes,and metaphase II (M2) oocytes in the blastocyst stage group. Considerably more cleavage stage embryos weretransferred compared to the number of transferred blastocysts (P=0.001). The blastocyst group had more vitrified embryosthan the cleavage group (P=0.000). The rates of implantation (P=0.332), chemical pregnancy (P=0.165), clinicalpregnancy (P=0.694), and live births (P=0.727) were higher in the blastocyst group, but they were not significantlydifferent. The rate of abortion was also not significantly higher in the blastocyst group (P=0.296).Conclusion: Blastocysts transferred in the fresh cycle of an ICSI procedure may be more advantageous compared tocleavage stage embryo transfer (registration number: IRCT20181030041503N1).

Keywords

• ivf/icsi
• blastocyst stage
• cleavage stage
• pregnancy outcomes
• embryo transfer