- 1Preimplantation genetic testing for aneuploidy is a screening test for aneuploidy; its precise sensitivity and specificity are not known because of limited available data.
- 2Blastocyst mosaicism can contribute to errors (false positive and false negative results) in preimplantation genetic testing for aneuploidy and the results may or may not reflect the chromosomal complement of the inner cell mass.
- 3Traditional prenatal genetic screening algorithms for trisomies 21 and 18 are not appropriate for pregnancies conceived after preimplantation genetic testing for aneuploidy and euploid embryo transfer.
- 4Given the performance of preimplantation genetic testing for aneuploidy as a screening test, multiple marker screening (including enhanced first-trimester screening) for trisomies 21 and 18 is not recommended for pregnancies conceived after preimplantation genetic testing for aneuploidy and euploid embryo transfer.
- 5Non-invasive prenatal testing using maternal plasma circulating cell-free DNA for common aneuploidies can be considered for pregnancies conceived after preimplantation genetic testing for aneuploidy and euploid embryo transfer in combination with thorough genetic counselling of the patient.
- 6Universal screening for adverse pregnancy outcomes using maternal serum markers for aneuploidy is currently not recommended outside of an investigational protocol and with informed consent. This recommendation applies to pregnancies conceived by in vitro fertilization with or without preimplantation genetic testing for aneuploidy.
- 7All women who conceive after euploid embryo transfer with preimplantation genetic testing for aneuploidy should be offered an ultrasound scan between 110 and 140 weeks gestation.
- 8Any abnormal findings at the time of the ultrasound scan at 110 to 140 gestation should prompt a referral for consideration of invasive diagnostic testing, irrespective of history of preimplantation genetic testing for aneuploidy and euploid embryo transfer.
- 9Invasive diagnostic testing is not recommended for pregnancies conceived after preimplantation genetic testing for aneuploidy and transfer of a euploid embryo unless abnormal findings are detected on ultrasound or non-invasive prenatal testing indicates a high risk of aneuploidy.
- 10Genetic counselling is strongly recommended for all women considering the transfer of a mosaic embryo.
- 11All women who become pregnant after preimplantation genetic testing for aneuploidy and mosaic embryo transfer should be offered an ultrasound scan between 110 and 140 weeks gestation.
- 12Multiple marker screening is not recommended for pregnancies conceived after preimplantation genetic testing for aneuploidy and mosaic embryo transfer.
- 13Non-invasive prenatal testing is not recommended for pregnancies conceived after preimplantation genetic testing for aneuploidy and mosaic embryo transfer.
- 14In pregnancies conceived after mosaic embryo transfer, invasive diagnostic testing is highly recommended, with amniocentesis strongly preferred over chorionic villus sampling.
- 15Consultation with the genetic laboratory should take place prior to any invasive diagnostic procedure to ensure appropriate testing is initiated based on the results of preimplantation genetic testing for aneuploidy.
ABBREVIATIONS:IVF (in vitro fertilization), NGS (next-generation sequencing), NIPT (non-invasive prenatal testing), PGT-A (preimplantation genetic testing for aneuploidy), PGT-M (preimplantation genetic testing for monogenic diseases), PGT-SR (preimplantation genetic testing for structural rearrangements), SNP (single nucleotide polymorphism)
Purchase one-time access:Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
One-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:Subscribe to Journal of Obstetrics and Gynaecology Canada
- In vitro culture of human blastocysts.in: Jansen R Mortimer D Towards reproductive certainty: fertility and genetics beyond 1999: the plenary proceedings of the 11th World Congress on in vitro fertilization & human reproductive genetics. Pearl River. Parthenon, NY1999: 378-388
- The International Glossary on Infertility and Fertility Care, 2017.Hum Reprod. 2017; 32: 1786-1801
- Validation of next-generation sequencing for comprehensive chromosome screening of embryos.Reprod Biomed Online. 2015; 31: 760-769
- Technical update 323: preimplantation genetic diagnosis and screening.J Obstet Gynaecol Can. 2015; 37: 451-463
- In vitro fertilization with single euploid blastocyst transfer: a randomized controlled trial.Fertil Steril. 2013; 100: 100-107
- Obstetrical and neonatal outcomes from the BEST trial: single embryo transfer with aneuploidy screening improves outcomes after in vitro fertilization without compromising delivery rates.Am J Obstet Gynecol. 2014; 210 (e1–6): 157
- Selection of euploid blastocysts for cryopreservation with array comparative genomic hybridization (aCGH) results in increased implantation rates in subsequent frozen and thawed embryo transfer cycles.Mol Cytogenet. 2013; 6: 32
- Selection of single blastocysts for fresh transfer via standard morphology assessment alone and with array CGH for good prognosis IVF patients: results from a randomized pilot study.Mol Cytogenet. 2012; 5: 24
- Blastocyst biopsy with comprehensive chromosome screening and fresh embryo transfer significantly increases in vitro fertilization implantation and delivery rates: a randomized controlled trial.Fertil Steril. 2013; 100: 697-703
- Global multicenter randomized controlled trial comparing single embryo transfer with embryo selected by preimplantation genetic screening using next-generation sequencing versus morphologic assessment.Fertil Steril. 2017; 108: e19
- Should every embryo undergo preimplantation genetic testing for aneuploidy? A review of the modern approach to in vitro fertilization.Best Pract Res Clin Obstet Gynaecol. 2018; 53: 38-47
- The pros and cons of preimplantation genetic testing for aneuploidy: clinical and laboratory perspectives.Fertil Steril. 2018; 110: 353-361
- The cytogenetic constitution of human blastocysts: insights from comprehensive chromosome screening strategies.Hum Reprod Update. 2019; 25: 15-33
- Comprehensive chromosome screening is highly predictive of the reproductive potential of human embryos: a prospective, blinded, nonselection study.Fertil Steril. 2012; 97: 870-875
- Assessment of aneuploidy concordance between clinical trophectoderm biopsy and blastocyst.Hum Reprod. 2019; 34: 181-192
- Comprehensive molecular cytogenetic analysis of the human blastocyst stage.Hum Reprod. 2008; 23: 2596-2608
- Comprehensive analysis of karyotypic mosaicism between trophectoderm and inner cell mass.Mol Hum Reprod. 2010; 16: 944-949
- DNA microarray reveals that high proportions of human blastocysts from women of advanced maternal age are aneuploid and mosaic.Biol Reprod. 2012; 87: 148
- Preimplantation genetic screening- the required RCT that has not yet been carried out.Reprod Biol Endocrinol. 2016; 14: 35
- Re-analysis of aneuploidy blastocysts with an inner cell mass and different regional trophectoderm cells.J Assist Reprod Genet. 2017; 34: 487-493
- Discrepant diagnosis rate of array comparative genomic hybridization in thawed euploid blastocysts.J Assist Reprod Genet. 2016; 33: 893-897
- Clinically recognizable error rate after the transfer of comprehensive chromosomal screened euploid embryos is low.Fertil Steril. 2014; 102: 1613-1618
- Chromosome mosaicism in human embryos.Biol Reprod. 1994; 51: 373-379
- Healthy babies after intrauterine transfer of mosaic aneuploid blastocysts.N Engl J Med. 2015; 373: 2089-2090
- Detailed investigation into the cytogenetic constitution and pregnancy outcome of replacing mosaic blastocysts detected with the use of high-resolution next-generation sequencing.Fertil Steril. 2017; 108 (e8): 62-71
- Extent of chromosomal mosaicism influences the clinical outcome of in vitro fertilization treatments.Fertil Steril. 2018; 109: 77-83
- Prenatal screening for fetal aneuploidy in singleton pregnancies.J Obstet Gynaecol Can. 2011; 33: 736-750
- Position statement from the Chromosome Abnormality Screening Committee on behalf of the Board of the International Society for Prenatal Diagnosis.Prenat Diagn. 2015; 35: 725-734
- Practice bulletin no. 163: screening for fetal aneuploidy.Obstet Gynecol. 2016; 127: e123-e137
- The first 3,000 non-invasive prenatal tests (NIPT) with the Harmony test in Belgium and the Netherlands.Facts Views Vis Obgyn. 2014; 6: 7-12
- Obstetrical complications associated with abnormal maternal serum markers analytes.J Obstet Gynaecol Can. 2008; 30: 918-932
- Prediction of adverse pregnancy outcomes by combinations of first and second trimester biochemistry markers used in the routine prenatal screening of Down syndrome.Prenat Diagn. 2010; 30: 471-477
- Prediction of obstetrical risk using maternal serum markers and clinical risk factors: serum markers and obstetrical history for obstetrical risk prediction.Prenat Diagn. 2014; 34: 172-179
- No. 348-joint SOGC-CCMG guideline: update on prenatal screening for fetal aneuploidy, fetal anomalies, and adverse pregnancy outcomes.J Obstet Gynaecol Can. 2017; 39: 805-817
- Mosaicism: “survival of the fittest” versus “no embryo left behind.”.Fertil Steril. 2016; 105: 1146-1149
PGDIS Position Statement on Mosaic Embryos. Available atwww.pgdis.org/docs/newsletter_071816.html. Accessed January 3, 2020.
- Analysis of implantation and ongoing pregnancy rates following the transfer of mosaic diploid–aneuploid blastocysts.Hum Genet. 2017; 136: 805-819
- Counselling considerations for chromosomal mosaicism detected by preimplantation genetic screening.Reprod Biomed Online. 2017; 34: 369-374
- Current experience concerning mosaic embryos diagnosed during preimplantation genetic screening.Fertil Steril. 2017; 107: 1113-1119
- Diagnosis and clinical management of embryonic mosaicism.Fertil Steril. 2017; 107: 6-11
- What are patients doing with their mosaic embryos? Decision making after genetic counseling.Fertil Steril. 2019; 111 (e1): 132-137
- An evidence-based scoring system for prioritizing mosaic aneuploid embryos following preimplantation genetic screening.Reprod Biomed Online. 2018; 36: 442-449
This document reflects emerging clinical and scientific advances as of the publication date and is subject to change. The information is not meant to dictate an exclusive course of treatment or procedure. Institutions are free to amend the recommendations. The SOGC suggests, however, that they adequately document any such amendments.
Informed Consent: Everyone has the right and responsibility to make informed decisions about their care together with their health care providers. In order to facilitate this, the SOGC recommends that they provide their patients with information and support that is evidence-based, culturally appropriate, and personalized.
Language and Inclusivity: This document uses gendered language in order to facilitate plain language writing but is meant to be inclusive of all individuals, including those who do not identify as a woman/female. The SOGC recognizes and respects the rights of all people for whom the information in this document may apply, including but not limited to transgender, non-binary, and intersex people. The SOGC encourages health care providers to engage in respectful conversation with their patients about their gender identity and preferred gender pronouns and to apply these guidelines in a way that is sensitive to each person's needs.
Copyright: The contents of this document cannot be reproduced in any form, in whole or in part, without prior written permission of the publisher of the Journal of Obstetrics and Gynaecology Canada.