Downloaded from http://perspectivesinmedicine.cshlp.org/ on September 27, 2021 - Published by Cold Spring Harbor Laboratory Press Genetic Counseling and Assisted Reproductive Technologies Debra Lilienthal1 and Michelle Cahr2 1The Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, New York 10021, USA 2California Cryobank Life Sciences, Los Angeles, California 90025, USA Correspondence: [email protected] Despite the ever-increasing number of patients undergoing fertility treatments and the ex- panded use of genetic testing in this context, there has been limited focus in the literature on the involvement of genetics professionals in the assisted reproductive technology (ART) setting. Here we discuss the importance of genetic counseling within reproductive medicine. We review how genetic testing of embryos is performed, the process of gamete donation, the challenges associated with genetic testing, and the complexities of genetic test result inter- pretation. n 2018, Louise Brown, the first child born from bearing, both of which correlate with reduced Iin vitro fertilization (IVF), turned 40 yr old fertility, these numbers are expected to continue (Steptoe and Edwards 1978; Fishel 2018). For to rise (Botting and Dunnell 2000; Armstrong people who were previously unable to have a and Akande 2013). biological child, the ability to conceive via IVF Advances in genetic testing have become in- meant that their dream of parenthood had a creasingly intertwined with the world of IVF, greater chance of becoming a reality. IVF has and are critical components of reproductive come a long way over the last four decades, medicine. Given the complexity of these ad- and the number of children born following the vances, the inclusion of trained genetics profes- use of assisted reproductive technology (ART) sionals within the field of ART is vital. www.perspectivesinmedicine.org continues to grow rapidly. In 2016 alone, data from the Centers for Disease Control and Pre- BACKGROUND vention reported 263,577 IVF cycles, resulting in 76,930 total infants born; the number of IVF There are many reasons for individuals and cycles documented between January 9, 1969 and couples to seek out ART, including female infer- August 1, 1978 was 457, resulting in two live tility, male factor infertility, unexplained in- births (Centers for Disease Control and Preven- fertility, secondary infertility (infertility after a tion 2018; Fishel 2018). Given the societal trends previous successful pregnancy), and the use of a of increasing parental age and delayed child- gestational carrier. Some who choose to use Editors: Laura Hercher, Barbara Biesecker, and Jehannine C. Austin Additional Perspectives on Genetic Counseling: Clinical Practice and Ethical Considerations available at www.perspectivesinmedicine.org Copyright © 2020 Cold Spring Harbor Laboratory Press; all rights reserved; doi: 10.1101/cshperspect.a036566 Cite this article as Cold Spring Harb Perspect Med 2020;10:a036566 1 Downloaded from http://perspectivesinmedicine.cshlp.org/ on September 27, 2021 - Published by Cold Spring Harbor Laboratory Press D. Lilienthal and M. Cahr ART do not meet the traditional definition duced in one cycle. During this stage, near-daily of infertility (i.e., not conceiving after 6 or 12 monitoring by blood and ultrasound occurs in months of unprotected intercourse, depending order for the physician to assess the response to on age); this includes individuals wishing to pre- treatment and determine when the oocytes are vent genetic disease, same-sex couples, or single mature and ready for retrieval. When the oo- patients who require donor gametes, those cytes appear to be potentially mature, the patient pursuing sex selection, and those interested in is given medication to trigger ovulation and un- fertility preservation. Fertility preservation may dergoes surgery to remove the oocytes (egg re- be used when health-related issues or medical trieval). Following retrieval, mature oocytes are treatments affect future fertility, such as gona- fertilized with the designated sperm sample in dotoxic treatments for cancer or delayed child- the laboratory and embryo development is mon- bearing. The reasons for seeking treatment will itored. Embryo(s) are usually transferred into likely continue to change over time. the uterus on the third or fifth day of develop- Before initiating any form of treatment, ment. Excess embryos may be cryopreserved for American Society for Reproductive Medicine later use. (ASRM) guidelines suggest a thorough evalua- Oocytes are fertilized either by insemination, tion including a physical exam and laboratory in which they are mixed with sperm in a Petri testing (Practice Committee of the American dish, or by ICSI, in which a single sperm is in- Society for Reproductive 2015a,b). This evalua- jected into the oocyte. The sperm source may be tion should elicit personal and family history of a fresh ejaculate from the patient’s partner, fro- genetic disease and review any prior genetic zen sperm from the patient’s partner, or sperm test results (i.e., chromosome analysis, carrier obtained via microsurgical epididymal sperm screening, etc.) that could affect the course of aspiration (MESA) or testicular sperm extraction treatment. Patients should also be counseled (TESE). Alternatively, patients may use frozen about additional genetic testing that may be in- sperm from an anonymous donor or a directed dicated before starting treatment. When issues donor, who may be a friend or a family member. arise as a result of this evaluation, referral to a ICSI was first used to treat male factor infer- genetics specialist is recommended. tility for cases in which IVF by insemination did ART is not synonymous with IVF and less- not lead to fertilization, or when a man had few invasive treatments may be an appropriate first sperm (Lanzendorf et al. 1988). ICSI is now also step in many instances. For some individuals used in situations in which there is no male fac- and couples, initial approaches may include tor infertility, such as with PGT, to reduce the timed intercourse or intrauterine insemination potential paternal contamination of the DNA www.perspectivesinmedicine.org (IUI). Reasons to consider IVF as a first-line tested from extraneous sperm that are not fertil- therapy include the need for any of the follow- izing the oocyte. ICSI is also used to fertilize ing: preimplantation genetic testing (PGT), a frozen oocytes or to maximize fertilization if gestational carrier, donor oocytes, or intracyto- only few or poor-quality oocytes are retrieved. plasmic sperm injection (ICSI) for patients with As mentioned above, following fertilization significant male factor infertility. Regardless of embryos are monitored for cell division. For pa- the indication, it is important to note that the tients trying to achieve pregnancy within the cy- IVF process can be physically, emotionally, and cle, embryo(s) are selected for transfer to the financially demanding. uterus. Experienced embryologists carefully as- sessembryoquantityandqualitytoselectthebest embryo(s) and also determine the day of embryo IVF BASICS transfer, which varies from center to center. The process of IVF begins with ovarian stimu- Vitrification, a method of rapid freezing, is lation. Injectable gonadotropin medications are currently the most widely used technique for given to stimulate the ovaries to produce more cryopreservation, the process of freezing repro- mature oocytes than could naturally be pro- ductive tissue (Practice Committees of American 2 Cite this article as Cold Spring Harb Perspect Med 2020;10:a036566 Downloaded from http://perspectivesinmedicine.cshlp.org/ on September 27, 2021 - Published by Cold Spring Harbor Laboratory Press Genetic Counseling and Assisted Reproduction Society for Reproductive and Society for Assisted them to request special prenatal diagnostic test- Reproductive 2013). Some patients choose to ing for chromosome abnormalities and/or im- cryopreserve all of their suitable embryos with- printing defects. out transferring any fresh embryos during the cycle. Patients who require up-front cryo- preservation include those who do not have GENETIC TESTING OF EMBRYOS medical clearance to achieve pregnancy, those Preimplantation Genetic Testing Overview who are using a gestational carrier, and those who are undergoing PGT or fertility preserva- PGT involves the removal of one or more nuclei tion. A frozen embryo transfer (FET) is the pro- from an oocyte (polar body biopsy) or an em- cess by which a frozen embryo is thawed and bryo (blastomere or trophectoderm cells) to test transferred into a woman’s uterus in a subse- for mutations or aneuploidy prior to embryo quent cycle. transfer (Practice Committee of the Society for The potential risks to offspring conceived by Assisted Reproductive and Practice Committee ART have been debated since its early days. Any of the American Society for Reproductive 2008). potential risks of ART treatments must be care- The purpose of PGT is to reduce the risk of fully weighed against their benefits for individ- having a child with a genetic disorder or a chro- uals and couples who may not otherwise be able mosome abnormality. to conceive. There are three types of PGT. PGT for In any pregnancy, there is a baseline risk of aneuploidy (PGT-A; previously called PGS) is 3%–4% for a child to have a birth defect or devel- the testing of embryos for chromosome abnor- opmental abnormality (Bodurtha and Strauss