Idiopathic recurrent miscarriage is caused mostly by aneuploid embryos.

Area of Science:

• Reproductive Medicine
• Human Genetics
• Embryology

Background:

• Idiopathic recurrent pregnancy loss (RPL) affects couples with two or more pregnancy losses.
• Chromosomal abnormalities in embryos are suspected contributors to RPL.
• Preimplantation genetic screening (PGS) aims to identify viable embryos for transfer.

Purpose of the Study:

• To evaluate the efficacy of PGS using array comparative genomic hybridization (aCGH) in idiopathic RPL patients.
• To compare miscarriage rates in PGS-treated RPL patients with expected rates.

Main Methods:

• A case series involving 287 cycles from couples with idiopathic RPL across multiple fertility centers.
• Embryo biopsy performed on day 3 (193 cycles) or at the blastocyst stage (94 cycles).
• Analysis of embryo chromosomal content using aCGH to determine euploidy rates.

Main Results:

• Analysis of 2,282 embryos revealed 35% euploidy and 60% aneuploidy rates.
• In 181 embryo transfer cycles, 100 resulted in pregnancy (55%), with a 45% implantation rate.
• A significantly reduced miscarriage rate of 6.9% was observed, compared to expected rates of 33.5% (RPL controls) and 23.7% (infertile controls).

Conclusions:

• PGS with aCGH demonstrates a substantial reduction in miscarriage rates for idiopathic RPL patients.
• High pregnancy and ongoing pregnancy rates were achieved in the study cohort.
• The findings strongly suggest that embryonic chromosomal abnormalities are a major cause of idiopathic recurrent miscarriage.