S.J. Morin

Levels of trophectoderm mitochondrial DNA do not predict the reproductive potential of sibling embryos

Abstract STUDY QUESTION What is the predictive value of trophectoderm mitochondrial DNA (mtDNA) quantity for blastocyst reproductive potential? SUMMARY ANSWER This study demonstrates that, within a given cohort, mtDNA quantitation does not distinguish between embryos that implant and embryos that do not implant after double embryo transfer (DET). WHAT IS ALREADY KNOWN An association between implantation failure and increased quantities of mtDNA has been observed in two studies but not in a third. STUDY DESIGN, SIZE AND DURATION A total of 187 patients (nine who received donor oocytes) with DET of one male and one female euploid blastocyst were included in this retrospective study, with 69 singleton deliveries providing the primary dataset to evaluate the predictive value of mtDNA for reproductive potential between January 2010 and July 2016. PARTICIPANTS/MATERIALS, SETTING AND METHOD MtDNA was quantified in cell lines to validate the quantitative PCR assay on limited quantities of starting material and then applied to 374 blastocyst biopsies. Pregnancies resulting in a singleton outcome were analyzed and newborn gender was utilized as a means to identify the implanted embryo. MtDNA quantity was then compared between implanted and non-implanted embryos in order to define the predictive value of mtDNA content for reproductive potential in this subset of patients. MAIN RESULTS AND THE ROLE OF CHANCE An initial comparison of mtDNA levels between all successful and unsuccessful embryos revealed no significant differences. In order to control for patient-specific variables, gender was subsequently used to identify the implanted embryo in DETs resulting in a singleton (n = 69). No systematic difference in relative mtDNA quantity was detected between implanted and non-implanted embryos. LIMITATIONS, REASONS FOR CAUTION This study was conducted at a single center and did not evaluate the entire cohort of embryos from each patient to evaluate cohort specific variation in mtDNA quantity. Although the largest of its kind so far, the sample size of DETs leading to a singleton was relatively small. WIDER IMPLICATIONS OF THE FINDINGS These data highlight the importance of control over patient-specific variables when evaluating candidate biomarkers of reproductive potential. All current available data suggest that mtDNA quantification needs further study before its clinical use to augment embryo selection. STUDY FUNDING/COMPETING INTERESTS The authors have no potential conflict of interest to declare. No external funding was obtained for this study. TRIAL REGISTRATION NUMBER Not applicable.

Translocations, inversions and other chromosome rearrangements

Chromosomal rearrangements have long been known to significantly impact fertility and miscarriage risk. Advancements in molecular diagnostics are challenging contemporary clinicians and patients in accurately characterizing the reproductive risk of a given abnormality. Initial attempts at preimplantation genetic diagnosis were limited by the inability to simultaneously evaluate aneuploidy and missed up to 70% of aneuploidy in chromosomes unrelated to the rearrangement. Contemporary platforms are more accurate and less susceptible to technical errors. These techniques also offer the ability to improve outcomes through diagnosis of uniparental disomy and may soon be able to consistently distinguish between normal and balanced translocation karyotypes. Although an accurate projection of the anticipated number of unbalanced embryos is not possible at present, confirmation of normal/balanced status results in high pregnancy rates (PRs) and diagnostic accuracy.

Combination of uterine natural killer cell immunoglobulin receptor haplotype and trophoblastic HLA-C ligand influences the risk of pregnancy loss: a retrospective cohort analysis of direct embryo genotyping data from euploid transfers

OBJECTIVE To compare maternal uterine natural killer cell immunoglobulin receptor (KIR) genotype and haplotype frequencies between patients whose euploid single-embryo transfer resulted in pregnancy loss and those that resulted in delivery and to determine if the risk of pregnancy loss was affected by the HLA-C genotype content in the embryo. DESIGN Retrospective cohort. SETTING Academic research center. PATIENT(S) Autologous fresh IVF cycles resulting in positive serum β-hCG during 2009-2014. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) 1) Relative risk of pregnancy loss according to maternal KIR genotypes and haplotypes. 2) Comparison of pregnancy loss rates within each KIR haplotype according to HLA-C ligand present in trophectoderm biopsy samples. RESULT(S) A total of 668 euploid single-embryo transfers with stored maternal DNA and available preamplification DNA from prior trophectoderm biopsy samples were studied. KIR2DS1, KIR3DS1, and KIR2DS5 were more common in patients who experienced pregnancy loss. Carriers of KIR A haplotype exhibited a decreased risk of pregnancy loss compared with KIR B haplotype carriers. However, among KIR A haplotype carriers, the risk of loss was significantly influenced by whether the transferred embryo carried a C1 allele versus no C1 alleles. CONCLUSION(S) KIR A haplotype carriers experienced fewer pregnancy losses than KIR B haplotype carriers after euploid single-embryo transfer. However, this risk was modified by HLA-C alleles present in the embryo. High-risk combinations (KIR A/homozygous C2 and KIR B/homozygous C1) resulted in a 51% increased risk of loss over all other combinations.

Endocrine Causes of Implantation Failure

Achieving successful implantation requires a complex endocrine stimulus of the endometrium. A deep understanding of this highly coordinated process is required for clinicians and investigators attempting to optimize an individual patient’s likelihood of success. Our current level of knowledge is the result of many elegant studies to elucidate these mechanisms. However, our tools for assessing the proper functioning of the endometrium in relation to hormonal response are limited. Modern infertility therapies that rely on gonadotropin stimulation undoubtedly change the chronology and histology of endometrium response. However, many patients achieve success despite these alterations. Patients with recurrent implantation failure, however, may be more sensitive to forces which change the normal physiologic state. Thus, careful attention to these issues in these patients is paramount. This chapter attempts to lay the groundwork for a comprehensive understanding of normal endometrial response, assess current diagnostic options and their limitations, and describe how pathological processes can disrupt normal implantation.

Diminished ovarian reserve and poor response to stimulation in patients <38 years old: a quantitative but not qualitative reduction in performance

STUDY QUESTION Do infertile women aged <38 years with quantitative evidence of diminished ovarian reserve and/or poor response to stimulation also exhibit poor oocyte quality as measured by blastulation rates, aneuploidy rates, and live birth rates? SUMMARY ANSWER Young women with evidence of accelerated follicular depletion, either by precycle ovarian reserve testing or postcycle evidence of low oocyte yield, exhibit equivalent blastulation rates, aneuploidy rates and live birth rates per euploid embryo transfer as age-matched controls with normal precycle and postcycle parameters. WHAT IS KNOWN ALREADY Previous studies are conflicted as to whether women with evidence of diminished ovarian reserve and/or poor ovarian response are also at increased risk of exhibiting evidence of poor oocyte quality. Most prior studies have failed to adequately control for the confounding effect of female age on typical markers of oocyte quality in poor responders. The rate of follicular depletion occurs at around 38 years on average; thus, evidence of quantitative depletion before this would indicate a premature diminution of ovarian reserve and allow evaluation of whether markers of oocyte quality are tied to quantitative markers. STUDY DESIGN, SIZE, DURATION This was a retrospective cohort study at a single center between 2012 and 2016. This time frame was specifically chosen as all embryos were cultured to the blastocyst stage at this center during the study period (no cleavage stage transfers were performed). Two comparisons were made: precycle assessment of ovarian reserve (based on anti-mullerian hormone (AMH) level) and postcycle oocyte yield results. For each comparison, patients in <10th percentile were compared to patients in the interquartile range (IQR) with respect to blastulation rate, aneuploidy rate and live birth rate. A mixed effects model was created to control for female age (in the <38 year old range) and correlation among oocytes from a given cohort. PARTICIPANTS/MATERIALS, SETTING, METHODS For the precycle blastulation analysis, only patients with AMH data available were included (345 patients with AMH in the <10th percentile versus 1758 patients with AMH in the 25th to 75th percentile (IQR)). To compare aneuploidy rates, the subset of these patients who pursued preimplantation genetic testing for aneuploidy (PGT-A) was then analyzed (124 patients in the <10th percentile versus 782 patients in the IQR). For the postcycle blastulation analysis, all patients who proceeded to retrieval (whether or not they also had AMH data available) were included (535 patients with oocyte yield in the <10th percentile versus 2675 patients in the IQR). To compare aneuploidy rates, the subset of these patients who pursued PGT-A was then analyzed (156 patients in the <10th percentile versus 1100 patients in the IQR). MAIN RESULTS AND THE ROLE OF CHANCE The adjusted odds of a given fertilized oocyte developing to a blastocyst, being aneuploid or leading to a live birth after euploid transfer were no different if the oocyte was retrieved from a cycle with ovarian reserve parameters or oocyte yield in the <10th percentile compared to an oocyte retrieved in a cycle with those parameters in the 25-75th percentile. An AMH level in the <10th percentile did more commonly result in cycle cancellation prior to retrieval and after retrieval prior to transfer due to global arrest of embryos. LIMITATIONS, REASONS FOR CAUTION The timing of retrieval in patients with fewer oocytes may be more optimal given the greater ability to discern the overall maturity of the cohort, thus enhancing performance per retrieved oocyte. Analyses included only first cycles. Subsequent adjustment of protocol due to prior performance may mean that some patients in the <10th percentile for oocyte yield are actually better prognosis patients than their first cycle indicates. Data on whether or not patients were on oral contraceptives at time that AMH level drawn was not available. Other unknown biases are also likely to be present given retrospective nature of the study. WIDER IMPLICATIONS OF THE FINDINGS While young women with evidence of quantitative depletion of ovarian reserve have lower live birth rates per stimulation cycle, this not attributable to poor oocyte quality because the blastulation rate per fertilized oocyte and live birth rate per embryo transfer are equivalent to that in women with normal quantitative markers of ovarian reserve. Thus, the pathophysiology mediating a premature quantitative decline in ovarian reserve appears different than that which mediates markers of oocyte quality, such as aneuploidy. Young poor responders may use this information to help guide embryo accumulation strategies when considering their family building plans. STUDY FUNDING/COMPETING INTEREST(S) None. TRIAL REGISTRATION NUMBER N/A.

Characterization of reproductive endocrinology and infertility (REI) fellowship applicants: guiding our mentees toward success

BackgroundAdvanced subspecialty training in reproductive endocrinology and infertility (REI) entails a competitive application process with many data points considered. It is not known what components weigh more heavily for applicants. Thus, we sought to study the REI fellow applicant and compare 1) those who apply but do not receive an interview, 2) those who receive an interview but do not match, and 3) those who successfully match.MethodsThis retrospective cohort study was conducted at a single REI fellowship program from 2013 to 2017. Academic variables assessed included standardized test scores and total number of publications listed on their curriculum vitae. Logistic regression models were constructed to determine variables that were predictive of being offered an interview in our program and of matching in any program.ResultsThere were 270 applicants, of which 102 were offered interviews. Interviewed applicants had significantly higher mean USMLE 1 and CREOG scores, as well as total publications and total abstracts. There was no difference in Step 2 and Step 3 scores or in number of book chapters. Of those interviewed, USMLE scores remained predictive of matching in any program; however, publications and scientific abstracts were no longer predictive.ConclusionsThe decision to offer applicants interviews appears to be influenced by objective standardized test scores, as well as a threshold of academic productivity. These items are less predictive of matching once the interview process begins, indicating that other factors, such as performance during the interview day, may be more heavily weighted.