Objective: To determine if cleavage- or blastocyst-stage embryo biopsy affects reproductive competence.

Design: Paired randomized clinical trial.

Setting: Academic-assisted reproduction program.

Patient(s): Attempting conception through IVF.

Intervention(s): After selecting two embryos for transfer, one was randomized to biopsy and the other to control. Both were transferred within shortly thereafter. The biopsy was submitted for microarray analysis and single-nucleotide polymorphism (SNP) profiling. Buccal DNA obtained from the neonate after delivery had microarray analysis and SNP profile compared with that of the embryonic DNA. A match confirmed that the biopsied embryo implanted and developed to term, whereas a nonmatch indicated that the control embryo had led to the delivery.

Main outcome measure(s): Paired analysis of the delivery rates of the transferred embryos. Either twin delivery or failure to deliver represents equivalent outcomes for the biopsied and control embryos. In contrast, singletons were determined to be from the biopsied or the control embryo.

Result(s): Blastomere biopsy on day 3 of development resulted in a significant reduction in sustained implantation. Only 30% of biopsied embryos had sustained implantation and ultimately developed into live-born infants versus 50% of unbiopsied controls, a relative reduction of 39%. In contrast, sustained implantation rates were equivalent (51% vs. 54%) for biopsied and control blastocysts.

Conclusion(s): Cleavage-stage biopsy markedly reduced embryonic reproductive potential. In contrast, trophectoderm biopsy had no measurable impact and may be used safely when embryo biopsy is indicated.

Clinical trial registration number: NCT01219504.