Rates of live birth after mosaic embryo transfer compared with euploid embryo transfer

Abstract

Purpose: Mosaicism is a prevalent characteristic of human preimplantation embryos. This retrospective cohort study aimed to investigate pregnancy outcomes after transfer of mosaic or euploid embryos.

Methods: The embryos, which had been transferred as "euploidy," were processed using array-based comparative genomic hybridization (aCGH). The original aCGH charts of the transferred embryos were reanalyzed. Mosaic and control euploid embryos were defined according to log2 ratio calls.

Results: Overall, 102 embryos were determined to be mosaic, of which 101 were estimated to harbor no more than 50% aneuploid mosaicism. Additionally, 268 euploid embryos were matched as controls. The rates of live birth (46.6% vs. 59.1%, odds ratio (OR) 0.60, 95% confidence interval (CI) 0.38-0.95), and biochemical pregnancy (65.7% vs. 76.1%, OR 0.60, 95% CI 0.37-0.99) per transfer cycle were significantly lower after mosaic embryo transfer than after euploid embryo transfer. The rates of clinical pregnancy and pregnancy loss and the risks of obstetric outcomes did not differ significantly between the two groups.

Conclusions: Compared with euploid embryo transfer, mosaic embryo transfer is associated with a lower rate of live birth, which is mainly attributed to a decreased rate of conception. However, as mosaic embryo transfer yielded a live birth rate of 46.6%, patients without euploid embryos could be counseled regarding this alternative option.

Keywords: Embryo transfer; Live birth; Mosaic embryo; Mosaicism; Obstetric outcome.

Conflict of interest statement

The authors declare that they have no conflict of interest.

Figures

Fig. 1

Examples of aCGH plots of re-classified euploid and mosaic embryos. a Plot of a female euploid embryo of which the log2 ratio of all autosome clones clustered tightly around the 0 line, with a standard deviation (SD) within 0.1. b Plot of a male mosaic embryo containing estimated 20% mosaicism of whole chromosome 5 loss