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Impact of preimplantation genetic testing for aneuploidy on obstetrical practice

Chan, Yiu-man; Li, Tin-chiu; Poon, Liona C.Y.

Current Opinion in Obstetrics and Gynecology: April 2019 - Volume 31 - Issue 2 - p 127–131
doi: 10.1097/GCO.0000000000000521
PRENATAL DIAGNOSIS: Edited by Jane Chueh

Purpose of review To provide updated information on preimplantation genetic testing for aneuploidy (PGT-A), focusing on its implications on prenatal diagnostic approaches after transferal of mosaic aneuploid embryos.

Recent findings PGT-A is a technology to screen for chromosome aneuploidy or major chromosome structural rearrangement in embryos before implantation using different cytogenetic analyses. PGT-A has been shown to reduce the negative effect of increasing maternal age on in-vitro fertilization (IVF) outcomes. PGT-A also encourages clinicians and patients to accept single embryo transfer after IVF-PGT-A to reduce the chance of multiple pregnancies. However, mosaic aneuploid embryo may be encountered following PGT-A. Recent discussions have focused on the consideration of transferal of mosaic aneuploid embryos in couples with no euploid embryo following multiple trials of IVF-PGT-A. A risk score for each chromosome has been developed to prioritize which mosaic embryos should be considered for transfer. However, there is a lack of long-term outcome data following mosaic aneuploid embryo transfer.

Summary Recent advances in PGT-A increase the detection of embryos with mosaicism, which is associated with an increased risk of miscarriage, fetal mosaic aneuploidy, and uniparental disomy. Strategy in prenatal diagnostic testing after mosaic aneuploid embryo transfer is discussed in this review.

Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China

Correspondence to Liona C.Y. Poon, MD, Department of Obstetrics and Gynaecology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China. Tel: +852 35052582; fax: +852 26360008; e-mail:

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