Advancements and Applications of Preimplantation Genetic Testing in In Vitro Fertilization: A Comprehensive Review

Preimplantation genetic testing (PGT) has become an integral component of assisted reproductive technology (ART), offering couples the opportunity to screen embryos for genetic abnormalities before implantation during in vitro fertilization (IVF). This comprehensive review explores the advancements and applications of PGT in IVF, covering its various types, technological developments, clinical applications, efficacy, challenges, regulatory aspects, and future directions. The evolution of PGT techniques, including next-generation sequencing (NGS) and comparative genomic hybridization (CGH), has significantly enhanced the accuracy and reliability of genetic testing in embryos. PGT holds profound implications for the future of ART by improving IVF success rates, reducing the incidence of genetic disorders, and mitigating the emotional and financial burdens associated with failed pregnancies and genetic diseases. Recommendations for clinicians, researchers, and policymakers include staying updated on the latest PGT techniques and guidelines, exploring innovative technologies, establishing clear regulatory frameworks, and fostering collaboration to maximize the potential benefits of PGT in assisted reproduction. Overall, this review provides valuable insights into the current state of PGT and its implications for the field of reproductive medicine.

A Case Series Based on the Mixed Double-Embryo Transfer (MDET) Outcome in Patients With Recurrent Implantation Failure

Successful implantation of embryos depends on the synchronous cross-talks between the endometrial wall and the competent blastocyst within the window of implantation (WOI). Hence, the WOI has a major significance in assisted reproductive technology (ART). However, in some cases, women do not have fixed WOI in ART cycles in order to enhance the rate of successful clinical pregnancy. However, there have been stances where women do not have a fixed WOI, and it shifts in subsequent menstrual periods. This contributes to the chances of recurrent implantation failure (RIF). Another factor that contributes to RIF is erratic endometrial receptivity, which hinders the chances of successful implantation of the conceptus in the endometrium. This case series consists of four case studies where the patients were believed to be suffering from RIF due to variable WOI or erratic endometrial receptivity and the routine protocol followed nowadays failed to make them conceive. In order to resolve the condition, we proposed a novel strategy in an attempt to improve pregnancy rates in these cases. An innovative method of embryo transfer known as mixed double-embryo transfer (MDET), which involved the transfer of one day 3 embryo and one day 5 blastocyst on day 6 of progesterone, led to possible pregnancy outcomes. A viable pregnancy was validated based on the human chorionic gonadotropin (β-hCG) test report, and two of the cases delivered healthy babies. Thus, this case series provides a unique approach to addressing the issues of RIF. However, larger studies are required to validate the possible use of this technique.

Sexual and Reproductive Health Among Men With Cystic Fibrosis

Cystic fibrosis (CF) is a genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Due to the distribution of the CFTR protein, CF presents with a heterogeneous phenotype. Men with CF may present with infertility due to congenital abnormalities of the vas deferens. In addition, they may experience testosterone deficiency. Today, they can father biological children with assisted reproductive technologies. We reviewed the current literature on the pathophysiology of these conditions, describe interventions that allow men with CF to conceive biological children, and provide recommendations for management of CF patients with reproductive health concerns.

Microscopic Epididymal Sperm Aspiration (MESA) Should be Employed Over Testicular Sperm Extraction (TESE) Sperm Retrieval Surgery for Obstructive Azoospermia (OA)

INTRODUCTION

 Testicular sperm extraction (TESE) has been widely used as a sperm extraction surgery for azoospermia even for obstructive azoospermia (OA) because it does not require surgical skill. However, there are postoperative pain issues, and subsequent testicular atrophy and decreased testosterone levels may occur with TESE. This study examines the usefulness of microscopic epididymal sperm aspiration (MESA) for OA.

METHODS

 We studied 108 patients diagnosed with OA and treated with MESA at our institute between April 2004 and December 2021. The MESA was performed using a micropipette with a micropuncture technique under an operative microscope. When no sperm were present or motility was not observed, additional punctures to the epididymal tubule were performed.

RESULTS

 Motile sperm were recovered in all cases (108 cases). Of these, intracytoplasmic sperm injection (ICSI) using frozen-thawed sperm was performed in 101 cases and the normal fertilization rate was 76.2%. A total of 436 embryo transfer (ET) cycles were performed. The implantation rate per transfer cycle was 47.9%, the clinical pregnancy rate was 41.0%, and the live birth rate was 23.7%. The per-case live birth rate was 84.8%.

CONCLUSIONS

 MESA-ICSI has a very good fertilization rate, clinical pregnancy rate, and delivery rate. Furthermore, the patient's postoperative pain is less, the number of sperm collected is larger, the burden on the embryologist who processes the collected sperm is less, and ICSI can be easily attempted after frozen-thawed sperm. MESA rather than TESE should be employed for the OA subjects.

The Effect of Hormonal Contraception Use on Ovarian Reserve Markers and the Uptake of Assisted Reproductive Technology in Individuals Seeking an Infertility Evaluation

Background and objective The effects of hormonal contraception (HC) use on ovarian reserve (OR) markers in individuals seeking an infertility evaluation and the success of assisted reproductive technology (ART) warrant further investigation. Therefore, the aim of this study was to determine if women seeking an evaluation for unexplained infertility who used long-term (≥2 years) HC have lower ovarian reserve (OR) markers and higher uptake of ART compared to short-term (<2 years) or never HC users. Methods We performed a cross-sectional patient survey involving a retrospective medical chart review of patients seeking an evaluation for unexplained infertility at the University of Colorado Advanced Reproductive Medicine (CU ARM) clinic. Results Most participants (87%; 107/123) reported a history of HC use with 98 (79.7%) reporting long-term continuous use for two or more years. Median OR markers were similar between long-term and short-term/never HC users [anti-Müllerian hormone (AMH): 2.4 vs. 3.2, p=0.20; antral follicle count (AFC): 18 vs. 26, p=0.10; follicle-stimulating hormone (FSH): 7.6 vs. 6.3, p=0.26] and remained so after adjusting for age and diagnosis of polycystic ovarian syndrome (PCOS) or primary ovarian insufficiency (POI) in linear regression models. However, among HC users aged less than 30 years (n=9), those who had discontinued HC between two and three years prior to the assessment of their OR markers had a 6.20 ng/mL increase in AMH level compared to those who had discontinued HC less than two years prior to the assessment (p=0.02). Additionally, there was a marginally increased use of ART overall among long-term HC users compared to short-term/never HC users (64.3% vs. 44.0%, p=0.06), specifically in the use of in vitro fertilization (IVF) (58.7% vs. 18.2%, p=0.01). Among long-term HC users, ovulation induction was less likely to result in live birth compared to short-term/never HC users (8.9% vs. 62.5%, p<0.001); however, after adjusting for age, PCOS, POI, and type of ART used, there was no difference in the odds of live birth after ART between long-term HC users and short-term/never users. Conclusion While long-term HC users report increased use of ART, in particular IVF, the overall conception rates and live birth outcomes among ART users do not appear to be significantly affected by a history of long-term HC use.

Assisted Reproductive Technology (ART): A Ray of Hope for Adolescent Idiopathic Premature Ovarian Failure

Adolescent idiopathic premature ovarian failure (POF) is extremely rare. In such conditions, there is a defect in the process of the folliculogenesis axis leading to a hypoestrogenic state and infertility. This disorder significantly impacts a woman's prospective health, fertility, and motherhood. A case of a 24-year-old female diagnosed with adolescent idiopathic premature ovarian failure under hormone replacement therapy who visited us for fertility management is discussed here. The couple underwent in vitro fertilization (IVF) using donor oocytes resulting in a twin pregnancy. The clinical significance of premature ovarian failure and subsequent reproductive guidance is highlighted in this case report.

Female obesity and infertility: outcomes and regulatory guidance

Obesity has been associated with reduced fertility, although the dynamics and mechanisms which link excess weight to reduced fertility are not yet fully clarified. Obese women, especially those with central obesity, are less likely to conceive per cycle. Obese women suffer from perturbations of the hypothalamus-pituitary-ovary axis, disturbances of the menstrual cycle and are up to three times more likely to suffer from oligo/anovulation. A delicate hormonal balance regulates follicular development and the maturation of oocytes and it has been observed that obesity can alter the hormonal environment: adipocytes, in fact, are responsible for the production of a hormone called leptin (present in high quantities in obese women) which has been associated with reduced fecundity. In addition to compromising ovulation, obesity negatively affects the development and implantation of the endometrium. The expression of polycystic ovary syndrome (PCOS) is regulated, in part, by weight, so obese women with PCOS often have a more severe phenotype and higher subfertility rates. Furthermore, obesity impairs women's response to medically assisted procreation (MAP) treatments. The authors have set out to delineate a broad-ranging overview of obesity's impact on female fertility, by drawing upon sources spanning the 1994-2022 period. Assisted reproductive technology (ART) procedures are also discussed as they relate to obese patients. In addition the dynamics by which maternal obesity reportedly affects fetal, neonatal and child development have also been briefly enunciated.

Randomized, active-controlled, comparative phase 3 efficacy and safety equivalence trial of Ovaleap® (recombinant human follicle-stimulating hormone) in infertile women using assisted reproduction technology (ART)

BACKGROUND

Pharmacokinetic studies with XM17 (Ovaleap®), a recombinant human follicle-stimulating hormone (r-hFSH, follitropin alfa), have demonstrated good safety and tolerability in healthy women whose endogenous FSH levels were down-regulated with a long agonist protocol. In these studies, Ovaleap® pharmacokinetics were dose-proportional and bioequivalent to the reference follitropin alfa product (Gonal-f®). The objective of the present study is to determine whether Ovaleap® is equivalent to Gonal-f® with respect to the number of oocytes retrieved in infertile but ovulatory women undergoing assisted reproductive technology (ART) therapy.

METHODS

This multinational, multicenter, randomized (1:1), active-controlled, assessor-blind, comparative study included infertile normally gonadotrophic women 18 to 37 years old with a body mass index of 18 to 29 kg/m(2) and regular menstrual cycles of 21 to 35 days undergoing ART therapy. During a 5-day fixed-dose phase, women received 150 IU/day of Ovaleap® (n = 153) or Gonal-f® (n = 146), followed by an up to 15-day dose-adaptation phase during which doses could be adjusted every 3 to 5 days, up to a maximum of 450 IU/day. Ovaleap® was to be deemed equivalent to Gonal-f® if the two-sided 0.95 confidence interval (CI) for the difference in the number of oocytes retrieved fell within the equivalence range of ±3 oocytes.

RESULTS

Similar numbers of oocytes were retrieved in the 2 treatment groups. The mean ± SD number of oocytes retrieved was 12.2 ± 6.7 in the Ovaleap® group and 12.1 ± 6.7 in the Gonal-f® group (intent-to-treat [ITT] population). Regression analysis estimated a mean difference of 0.03 oocytes between the treatment groups (95 % CI: -0.76-0.82), which was well within the prespecified equivalence range of ±3 oocytes. Ovaleap® and Gonal-f® showed favorable and comparable safety profiles, with no unexpected safety findings.

CONCLUSIONS

Ovaleap® has shown the same efficacy and safety as Gonal-f® for stimulation of follicular development in infertile women (up to 37 years of age) who are undergoing ART therapy.

TRIAL REGISTRATION

EudraCT: 2009-017674-20. Current controlled trials: ISRCTN74772901 . Date of trial registration: 19 March 2010.

A global perspective on assisted reproductive technology fertility treatment: an 8-country fertility specialist survey

BACKGROUND

Procedures that may optimize success in achieving live births from assisted reproductive technology (ART) continue to be examined. Not yet considered are the perspectives of fertility specialists regarding important developments in the fertility treatment field, current unmet needs, and anticipated future advances. In the current study, an 8-country survey of fertility specialists was conducted to provide a comprehensive, global depiction of fertility treatments across different regions.

METHODS

Fertility specialists from France, Germany, Italy, Spain, the United Kingdom (UK), the United States (US), China, and Japan were invited to participate in an online survey. Participants were eligible if they personally managed ≥25 patients/month who were experiencing difficulty conceiving, and if they had performed ART fertility treatment with ≥1 patient in the previous month. Quantitative questions addressed the number of patients seen, main infertility causes, number of cycles performed, ART procedure type, and ART outcomes. Qualitative questions covered diagnostic trends, unmet needs, important advances, and expected future developments.

RESULTS

The number of fertility specialists who completed the survey included 29 in France, 33 in Germany, 23 in Italy, 38 in Spain, 34 in the UK, 91 in the US, 50 in China, and 65 in Japan. Patient volume increased over the prior 2 years according to 67 % (242/363) of the fertility specialists. As expected, ART outcomes all declined with age in all countries. ART outcomes varied by country, with the highest implantation, pregnancy, and live birth rates reported by fertility specialists in the US and China and the lowest rates reported in France and Italy. The most frequently reported unmet needs in fertility treatment were financial coverage, improved implantation rate, and egg donation. Most frequently named future advancements expected to change the fertility treatment field included improved embryo selection through imaging and/or metabolomics, improved embryo implantation rate, and use of preimplantation genetic diagnosis.

CONCLUSIONS

This study, which follows a rigorous survey methodology, elucidates the current state of fertility specialists' practices and perspectives on the global fertility treatment field, which highlights differences and similarities among countries. This research may inform further studies and procedural developments that might better improve and standardize ART.

Establishment of comparative performance criteria for IVF centers: correlation of live birth rates in autologous and donor oocyte IVF cycles

BACKGROUND

To assess whether an objective performance criterion for in vitro fertilization (IVF) centers can be established.

METHODS

A retrospective analysis of 2011 National ART Surveillance System data for 451 U.S. IVF centers, 137 of which were included in the analysis since they performed >20 fresh embryo transfers per age group and >20 fresh oocyte donor transfers. The analysis of autologous cycles was restricted to women under age 40. The main outcome measure was correlation between center-specific live birth rates (LBR) in autologous and donor oocyte cycles.

RESULTS

55.6% donor and 46.7%, 39.1% and 28.7% (for ages <35, 35-37 and 38-40 years) autologous cycles resulted in live births per fresh embryo transfer. Donor LBR predicted autologous LBR (< 35 years, P < 0.001; 35 - 38 years, P < 0.001; 38 - 40 years, P = 0.015). Clinics with high prevalence of patients with diminished ovarian reserve had lower autologous LBR per age group (P = 0.015). Every 10% increase in donor LBR increased odds of autologous LBR above the age-adjusted national average by 68% (OR 1.68; 95% CI 1.36 - 2.07; P < 0.001).

CONCLUSIONS

Since center-specific donor and autologous IVF cycle outcomes correlate, and as donor cycles reflect fewer patient covariates, they represent a first comparable performance measure between centers, allowing for internal as well as external quality control.

Evaluating a novel panel of sperm function tests for utility in predicting intracytoplasmic sperm injection (ICSI) outcome

PURPOSE

The objective of this study was to evaluate a panel of three sperm function tests; tests known to assess different aspects of sperm functionality and genomic integrity, the: 1) Sperm DNA Accelerated Decondensation (SDAD(TM)) Test, 2) Sperm DNA Decondensation (SDD(TM)) Test, and 3) Sperm Penetration Assay (SPA), determining if positive and negative test scores correlated with failed and successful ICSI outcomes, respectfully.

METHODS

A prospective, double blinded, cohort study was performed. One study sample (ejaculated semen) was collected by each of the 60 male partners of the 60 couples enrolled in the study; males whose female partners were found to have no major female factor issues. The sperm from each male was analyzed in the SPA, and SDAD and SDD Tests, and used for ICSI (1 ICSI cycle per couple).

RESULTS

The ICSI cycle pregnancy rate for this study was 50 %, with a delivery rate=40 % (n=60 ICSI cycles). The SPA and SDD Test scores did not significantly predict ICSI outcome when used as stand-alone tests (p>>0.05). However, when the SPA and SDD Test scores were used together, ICSI outcomes for a subgroup of 10 (16.7 %) males, were significantly predicted (p=0.03), with 1 live birth, and 9 negatives where the transferred embryos did not implant. In total, 38.4 % of the couples in this study were found to have a very poor chance for a successful ICSI cycle.

CONCLUSION

SDAD Test scores alone, and SPA and SDD Test scores used together, significantly predicted failed ICSI outcomes. This indicates that the scores obtained when analyzing patients' sperm using a panel of sperm function tests; specifically, the SPA, and SDAD and SDD Tests, can be used to identify infertile couples who should not be directed to ICSI.

Oocyte activation and phospholipase C zeta (PLCζ): diagnostic and therapeutic implications for assisted reproductive technology

Infertility affects one in seven couples globally and has recently been classified as a disease by the World Health Organisation (WHO). While in-vitro fertilisation (IVF) offers effective treatment for many infertile couples, cases exhibiting severe male infertility (19-57%) often remain difficult, if not impossible to treat. In such cases, intracytoplasmic sperm injection (ICSI), a technique in which a single sperm is microinjected into the oocyte, is implemented. However, 1-5% of ICSI cycles still fail to fertilise, affecting over 1000 couples per year in the UK alone. Pregnancy and delivery rates for IVF and ICSI rarely exceed 30% and 23% respectively. It is therefore imperative that Assisted Reproductive Technology (ART) protocols are constantly modified by associated research programmes, in order to provide patients with the best chances of conception. Prior to fertilisation, mature oocytes are arrested in the metaphase stage of the second meiotic division (MII), which must be alleviated to allow the cell cycle, and subsequent embryogenesis, to proceed. Alleviation occurs through a series of concurrent events, collectively termed 'oocyte activation'. In mammals, oocytes are activated by a series of intracellular calcium (Ca2+) oscillations following gamete fusion. Recent evidence implicates a sperm-specific phospholipase C, PLCzeta (PLCζ), introduced into the oocyte following membrane fusion as the factor responsible. This review summarises our current understanding of oocyte activation failure in human males, and describes recent advances in our knowledge linking certain cases of male infertility with defects in PLCζ expression and activity. Systematic literature searches were performed using PubMed and the ISI-Web of Knowledge. Databases compiled by the United Nations and World Health Organisation databases (UNWHO), and the Human Fertilization and Embryology Authority (HFEA) were also scrutinised. It is clear that PLCζ plays a fundamental role in the activation of mammalian oocytes, and that genetic, molecular, or biochemical perturbation of this key enzyme is strongly linked to human infertility where oocyte activation is deficient. Consequently, there is significant scope for our understanding of PLCζ to be translated to the ART clinic, both as a novel therapeutic agent with which to rescue oocyte activation deficiency (OAD), or as a prognostic/diagnostic biomarker of oocyte activation ability in target sperm samples.

Fertility therapies, infertility and autism spectrum disorders in the Nurses' Health Study II

BACKGROUND

An increasing number of women are utilizing fertility treatments, but little is known about their relation to autism spectrum disorders (ASD).

METHODS

To determine the association between maternal fertility therapy use and risk of having a child with ASD, we conducted a nested case-control study within the Nurses' Health Study II (n = 116,430). Maternally reported diagnoses of ASD were confirmed through a supplementary questionnaire and, in a subgroup, the Autism Diagnostic Interview-Revised. Controls were randomly selected by frequency matching to case children's year of birth. Associations were examined by self-reported infertility and type of therapy using conditional logistic regression.

RESULTS

In all, 9% of the 507 cases and 7% of 2,529 controls indicated fertility therapy use for the index pregnancy. No significant associations with self-reported fertility therapies or history of infertility were seen in primary analyses. In subgroup analyses of women with maternal age ≥ 35 years (n = 1,020), artificial insemination was significantly associated with ASD; ovulation inducing drug (OID) use was significantly associated in crude but not adjusted analyses (odds ratio 1.81, 95% CI 0.96-3.42). Results were similar by diagnostic subgroup, though within the advanced maternal age group, OID and artificial insemination were significantly associated with Asperger syndrome and pervasive developmental disorder not-otherwise specified, but not autistic disorder.

CONCLUSION

[corrected] Assisted reproductive therapy and history of infertility did not increase risk of having a child with ASD in this study. However, the associations observed with OID and artificial insemination among older mothers, for whom these exposures are more common, warrant further investigation.

Cloning in reproductive medicine

This review article summarizes the historical development of mammalian cloning, presents current advances and presumed risk factors in the field of reproductive cloning, discusses possible clinical applications of therapeutic and diagnostic cloning and outlines prospective commercial trends in pharmaceutical cloning. Predictable progress in biotechnology and stem cell engineering should prove to be advantageous for patients' health and for novel benefits in reproductive and regenerative medicine.

Emergency sperm extraction for transient erectile dysfunction prior to assisted conception

PURPOSE

During assisted conception treatment the male partner is under stress and consequently can fail to produce semen sample prior to egg collection. Failure to produce spermatozoa at a given time could lead to cancellation of the procedure.

METHODS

We report the use of emergency percutaneous epididymal sperm aspiration (PESA) for temporary erectile dysfunction in a couple undergoing in vitro fertilization treatment. In the last 2 years, we saw three men who failed to produce a semen sample on the day of their partners' egg collection procedure.

RESULTS

In the first case the male partner failed to produce semen after egg collection and the cycle was canceled. This clinical scenario was likely to recur and one of the options was to consider PESA. In the second case the male partner was counseled about the availability of PESA but he managed to produce spermatozoa at home. The third patient was unable to produce a semen sample despite being provided audiovisual support and being allowed to go home. Five hours after the egg collection, emergency PESA was performed after appropriate counseling. The procedure yielded motile spermatozoa which were used for intracytoplasmic sperm injection which resulted in successful fertilization, embryo transfer, and pregnancy.

CONCLUSIONS

This case emphasizes that surgical procedures, such as PESA,TESA, and TESE, are useful alternatives but should be the last option to obtain sperm for ART. Other nonsurgical procedures, such as audiovisual aids, producing sperm at home, and the use of sildenafil citrate (Viagra) must be offered first to men with temporary erectile dysfunction during ART treatment.