Gestational surrogacy and the role of routine embryo screening: Current challenges and future directions for preimplantation genetic testing

Abstract

Preimplantation genetic screening (PGS) is a component of IVF entailing selection of an embryo for transfer on the basis of chromosomal normalcy. If PGS were integrated with single embryo transfer (SET) in a surrogacy setting, this approach could improve pregnancy rates, minimize miscarriage risk, and limit multiple gestations. Even without PGS, pregnancy rates for IVF surrogacy cases are generally satisfactory, especially when treatment utilizes embryos derived from young oocytes and transferred to a healthy surrogate. However, there could be a more general role for PGS in surrogacy, since background aneuploidy in embryos remains a major factor driving implantation failure and miscarriage for all infertility patients. At present, the proportion of IVF cases involving GS is limited, while the number of IVF patients requesting PGS appears to be increasing. In this report, the relevance of PGS for surrogacy in the rapidly changing field of assisted fertility medicine is discussed.Birth Defects Research (Part C) 108:98-102, 2016.V C 2015 Wiley Periodicals, Inc.

Risks in Surrogacy Considering the Embryo: From the Preimplantation to the Gestational and Neonatal Period

“…Further to that point, these embryos may be subjected to genetic testing in the form of Preimplantation Genetic Screening (PGS). PGS may be employed in order to enhance and enrich selection criteria and identify the embryos carrying a balanced chromosomal complement, thus securing a healthy pregnancy [ 7 , 19 ]. In this section we highlight the negative implications related to the fact that surrogate babies are in fact IVF babies.…”

“…This could ensure that the possibility of miscarriage, termination of pregnancy, or live birth related to a compatible with gestation disorder is minimized. In case of chromosomal abnormalities and/or monogenic disorders, Preimplantation Genetic Diagnosis and Screening (PGD/PGS) excavate monogenic diseases and chromosomal abnormalities, numerical or structural, leading to the best embryo selection [ 7 , 19 , 32 ]. It is not uncommon for surrogacy to be proposed as the optimal approach instead of PDG/PGS application, in cases of patients with recurrent miscarriages or with a reproductive history of autoimmune loss of pregnancy [ 33 ].…”

“…It is not uncommon for surrogacy to be proposed as the optimal approach instead of PDG/PGS application, in cases of patients with recurrent miscarriages or with a reproductive history of autoimmune loss of pregnancy [ 33 ]. Given the option, it is possible that the commissioning couples decide to further subject the embryos—destined to be transferred to a surrogate uterus—to PGS on the grounds of acquiring more information on their genetic profile [ 7 ]. The further embryo manipulation may be opted for in order to enhance the selection of embryos to be transferred and therefore increase the pregnancy success rate [ 7 ].…”

“…Women with a severe Müllerian anomaly or a congenital absence of uterus and/or vagina are usual candidates for surrogacy. The condition of Mayer-Rokitansky-Küster-Hauser Syndrome characterized by a female genotype and phenotype and accompanied with a congenital aplasia of the uterus and the vagina [ 5 – 7 ] represents another category of patients requiring surrogacy. Further to the above, Complete Androgen Insensitivity Syndrome (CAIS syndrome) where the uterus and ovaries are absent [ 8 , 9 ], as well as women who have undergone hysterectomy, presents as only few of the cases where surrogacy is imperative and women may choose this as a path to parenthood.…”

Aneuploidy: a common and early evidence-based biomarker for carcinogens and reproductive toxicants

“…In the controlled setting of the assisted reproduction clinic, aneuploidy in the embryo is the most frequently observed cause of failure to achieve a pregnancy. In this context, opportunities for more fully assessing oocyte aneuploidy are promising because women may be willing to donate remainder oocytes for epidemiologic and mechanistic studies [ 153 – 155 ].…”