Preimplantation Genetic Testing for Aneuploidy: A Review.

IMPORTANCE: Preimplantation genetic testing for aneuploidy (PGT-A) has undergone many technical developments over recent years, including changes in biopsy timings, methodology, and genetic analysis techniques. The evidence surrounding the efficaciousness of PGT-A is sporadic and inconsistent; as such, significant doubt and concern remain regarding its widespread implementation. OBJECTIVE: This review seeks to describe the historical development of PGT-A and to analyze and summarize the current published literature. CONCLUSIONS: At times during its infancy, PGT-A failed to display conclusive improvements in results; with newer technologies, PGT-A appears to yield superior outcomes, including reductions in miscarriages and multiple gestations. Clinicians and patients should assess the use of PGT-A on a case-by-case basis, with laboratories encouraged to utilize blastocyst biopsy and next-generation sequencing when conducting PGT-A. Further studies providing cumulative live birth rates and time to live birth are required if PGT-A is to be proven as producing superior outcomes. RELEVANCE: PGT-A has the potential ability to impact in vitro fertilization success rates, and as it is increasingly adopted worldwide, it is crucial that clinicians are aware of the evidence for its continued use.

Gonadotropin-Releasing Hormone-Agonist Triggering and a Freeze-All Approach: The Final Step in Eliminating Ovarian Hyperstimulation Syndrome?

IMPORTANCE: In vitro fertilization (IVF) has evolved dramatically in recent decades; however, clinical practices have been slow to adopt these advancements, particularly regarding final oocyte maturation and the timing of embryo transfer. Concerns still exist over the ability of gonadotropin-releasing hormone (GnRH) agonists and elective embryo cryopreservation to reduce the risk of ovarian hyperstimulation syndrome (OHSS) without compromising pregnancy outcomes. OBJECTIVE: This review investigates IVF outcomes associated with GnRH-agonist triggering and elective embryo cryopreservation. The safety and efficacy of GnRH-agonist triggering are compared with conventional human chorionic gonadotropin triggering, and frozen embryo transfers are weighed against fresh transfers. EVIDENCE ACQUISITION: A literature search was conducted using OVID (MEDLINE) and PubMed databases. The search strategy included keywords such as "ovarian hyperstimulation syndrome or OHSS," "GnRH-agonist triggering," "cryopreservation or freeze-all," and "IVF outcomes." A total of 214 articles were considered for review. RESULTS: Gonadotropin-releasing hormone agonist triggering reduces OHSS incidence without compromising oocyte retrieval and fertilization rates in donor and autologous cycles. However, GnRH-agonist triggering causes a luteal phase deficiency in autologous cycles, deleteriously compromising pregnancy rates. Elective embryo cryopreservation overcomes this deficiency, reducing the risk of OHSS and may improve neonatal and obstetric outcomes. CONCLUSIONS: Gonadotropin-releasing hormone agonist triggering should be considered in all donor cycles. It should also be selectively considered in autologous cycles in combination with elective cryopreservation of all viable embryos.

Cryopreserved oocytes: update on clinical applications and success rates.

IMPORTANCE: Over the past 3 decades, oocyte cryopreservation procedures have improved rapidly. However, there is limited research reviewing the efficacy of different cooling protocols and inadequate data comparing in vitro fertilization (IVF) outcomes from fresh oocytes with cryopreserved oocytes. OBJECTIVE: The present review was performed to investigate advances in oocyte cryopreservation technologies and identify areas for further research, to determine whether results from IVF using cryopreserved oocytes are comparable to IVF using fresh oocytes, and to identify the patient populations requiring access to oocyte cryopreservation. EVIDENCE ACQUISITION: A literature review was conducted. OVID (MEDLINE) and PubMed databases were queried using phrases such as "oocyte or egg" and "cryopreservation," "vitrification," or "slow cooling or slow freezing." A total of 180 studies were selected for review. RESULTS: Current literature suggests that vitrified oocytes produce superior IVF results to slow-frozen oocytes and may yield comparable outcomes to IVF with fresh oocytes in certain patient populations. Patients at risk of infertility due to disease or age-related decline or oocyte donation programs, couples who fail to produce semen when required for IVF, and patients with legal or ethical reasons against embryo cryopreservation may access cryopreserved oocytes. CONCLUSIONS: We suggest that women who comprise the previously mentioned patient populations should be offered oocyte vitrification technology. Further research is required to confirm IVF success across all patient populations and determine the best cryopreservation protocols. RELEVANCE: This review will be relevant to clinicians interested in fertility treatments using cryopreserved oocytes, fertility preservation, oncology and fertility, and immunology and fertility.