Investigation of aneuploidy and mosaicism throughout pregnancies conceived through assisted reproductive technology (ART)
department or school: Medicine, Faculty of
department or school: Obstetrics and Gynaecology, Department of
data provider: DSpace
degree campus: UBCV
creator: Watt, Katherine
issued: 2019-07-04T18:56:22Z
issued: 2019
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Assisted Reproductive Technology (ART) has been used for nearly four decades to help infertile couples achieve pregnancy. Such pregnancies are at a greater risk of restricted fetal growth and preterm birth, though whether these risks arise from environmental factors imposed on embryos cultured in vitro, or from genetic or epigenetic factors related to underlying infertility of the parents, remains unclear. Embryos generated using ART are frequently mosaic – having at least two genetically distinct cell populations within the same embryo. Mosaicism that persists in the cells that form the placenta can be observed as confined placental mosaicism (CPM), wherein genetic imbalances that may be fatal for a fetus are tolerated in the placenta, albeit with consequences such as restricted fetal growth, premature birth, and fetal demise. To investigate whether genetic imbalances and mosaicism occur more frequently for ART conceptions, term placentas from in-vitro fertilization (IVF) conceptions were analyzed at three distinct sites for large variations in chromosomal copy number. The incidence of CPM (4/82, 4.9%) was not significantly greater than what has previously been observed in term placentas from spontaneous conceptions (8/528, 1.5%, P=0.064, Fisher’s Test). The presence of constitutional genetic abnormalities and mosaicism were also investigated by karyotyping live-born infants from ART and natural conception pregnancies, and abnormalities were detected at similar rates between IVF (3/220, 1.36%), intracytoplasmic sperm injection (ICSI) (4/255, 1.57%), and naturally conceived cases (5/336, 1.49%). My results support observations that ART pregnancies are not at significantly greater risk of chromosomal abnormality or mosaicism than spontaneous pregnancies, and suggest that the poorer perinatal outcomes observed for ART conceptions may be attributable to other factors, such as small copy number variation or epigenetics.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/70912
note: INVESTIGATION OF ANEUPLOIDY AND MOSAICISM THROUGHOUT PREGNANCIES CONCEIVED THROUGH ASSISTED REPRODUCTIVE TECHNOLOGY (ART) by Katherine Watt BSc,. The University of British Columbia, 2009 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in The Faculty of Graduate and Postdoctoral Studies (Reproductive and Developmental Sciences) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) June 2019 © Katherine Watt, 2019 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, a thesis/dissertation entitled: “Investigation of Aneuploidy and Mosaicism Throughout Pregnancies Achieved Through Assisted Reproductive Technology (ART)” submitted by Katherine Leigh Watt in partial fulfillment of the requirements for the degree of Master of Science in Reproductive and Developmental Sciences Examining Committee: Alexander Beristain Supervisor Wendy Robinson Chair Carolyn Brown Supervisory Committee Member Evica Separovic Additional Examiner Additional Supervisory Committee Members: Patrice Eydoux Supervisory Committee Member Timothy Rowe Supervisory Committee Member iii Abstract Assisted Reproductive Technology (ART) has been used for nearly four decades to help infertile couples achieve pregnancy. Such pregnancies are at a greater risk of restricted fetal growth and preterm birth, though whether these risks arise from environmental factors imposed on embryos cultured in vitro, or from genetic or epigenetic factors related to underlying infertility of the parents, remains unclear. Embryos generated using ART are frequently mosaic – having at least two genetically distinct cell populations within the same embryo. Mosaicism that persists in the cells that form the placenta can be observed as confined placental mosaicism (CPM), wherein genetic imbalances that may be fatal for a fetus are tolerated in the placenta, albeit with consequences such as restricted fetal …
has type: Thesis/Dissertation
date issued: 2019-09
is shown at: 10.14288/1.0379757
language: eng
degree discipline: Reproductive and Developmental Sciences
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/70912