Lessons from elective in vitro fertilization (IVF) in, principally, non-infertile women

The utility of all-freeze IVF cycles depends on the composition of study populations

BACKGROUND

Because often introduced without proper validation studies, so-called "add-ons" to IVF have adversely affected in vitro fertilization (IVF) outcomes worldwide. All-freeze cycles (embryo banking, EB) with subsequently deferred thaw cycles are such an "add-on" and, because of greatly diverging reported outcomes, have become increasingly controversial. Based on "modeling" with selected patient populations, we in this study investigated whether reported outcome discrepancies may be the consequence of biased patient selection.

RESULTS

In four distinct retrospective case control studies, we modeled in four cohort pairings how cryopreservation with subsequent thaw cycles affects outcomes differently in good-, average- and poor-prognosis patients: (i) 127 fresh vs. 193 frozen donor-recipient cycles to model best-prognosis patients; (ii) 741 autologous fresh non-donor IVF cycles vs. 217 autologous frozen non-donor IVF cycles to model average prognosis patients; (iii) 143 favorably selected autologous non-donor IVF cycles vs. the same 217 frozen autologous cycles non-donor to monitor good- vs. average-prognosis patients; and (iv) 598 average and poor-prognosis autologous non-donor cycles vs. the same 217 frozen autologous non-donor cycles to model poor vs. average prognosis patients. In best-prognosis patients, EB marginally improved IVF outcomes. In unselected patients, EB had no effects. In poor-prognosis patients, EB adversely affected IVF outcomes. Unexpectedly, the study also discovered independent-of-age-associated chromosomal abnormalities, a previously unreported effect of recipient age on miscarriage risk in donor-egg recipients.

CONCLUSIONS

In poor-prognosis patients, EB cycles should be considered contraindicated. In intermediate-prognosis patients EB does not appear to change outcomes, not warranting additional cost and time delays. Therefore, only good-prognosis patients are candidates for EB, though they will experience only marginal benefits that may not be cost-effective.

Antimüllerian hormone is not associated with embryo ploidy in patients with and without infertility undergoing in vitro fertilization with preimplantation genetic testing

OBJECTIVE

To assess the association between antimüllerian hormone (AMH) and embryo ploidy rates in 2 cohorts of patients undergoing in vitro fertilization (IVF) with trophectoderm biopsy for preimplantation genetic testing for aneuploidy (PGT-A): the general population of women pursuing IVF with PGT-A (Infertile cohort) and women pursuing IVF with preimplantation genetic testing for monogenic disorders (PGT-M) owing to the risk of hereditary monogenic diseases (Non-infertile cohort).

DESIGN

Retrospective cohort study.

SETTING

Academic center.

PATIENT(S)

Patients undergoing their first cycle of IVF with trophectoderm biopsy and PGT-A or PGT-A and PGT-M in our center between March 2012 and June 2020. Patients of advanced maternal age according to the Bologna criteria (age ≥40 years) and patients who underwent fresh embryo transfers were excluded.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Proportion of euploid, mosaic, and aneuploid embryos per cycle.

RESULT(S)

"Infertile" (n = 926) and "Non-infertile" (n = 214) patients were stratified on the basis of AMH levels, with low-AMH defined as <1.1 ng/mL in accordance with the Bologna criteria. Age-adjusted regression models showed no relationship between AMH classification and proportion of euploid, mosaic, and aneuploid embryos in the Infertile or Non-infertile cohorts. In the Infertile cohort, no association between AMH classification and embryo ploidy rates was identified in a subgroup analysis of patients aged <35 years, 35-37 years, and 38-39 years. These findings persisted in a sensitivity analysis of infertile patients stratified into AMH (ng/mL) quartile categories.

CONCLUSION(S)

No association was found between AMH and the proportion of euploid, mosaic, or aneuploid embryos in 2 large cohorts of patients undergoing IVF with PGT-A (Infertile patients) or PGT-A and PGT-M (Non-infertile patients), suggesting that a quantitative depletion of ovarian reserve does not predict the ploidy status of the embryo cohort.

Significant correlation between anti-müllerian hormone and embryo euploidy in a subpopulation of infertile patients

Anti-Müllerian hormone (AMH) is a standard marker of ovarian reserve. Correlation between AMH and egg euploidy is controversial. We evaluated the association between AMH and blastocyst euploidy rate examined by pre-implantation genetic screening (PGS). This retrospective study was conducted at the CReATe Fertility Centre. We included single IVF cycles of 216 infertile couples, which resulted in 911 blastocysts subjected to array comparative genomic hybridization and evaluated IVF outcome after embryo transfer. The average age and median AMH of female patients were 37.2 (SD = 3.8) and 20 pmol/l, respectively, and the average euploidy rate was 38.3%. Using multivariate regression controlling for age, antral follicle count, body mass index and parity, there was a significant association between serum AMH and proportion of euploid embryos (P = 0.02), due to the dominant ≤36 age group in which significant correlation between AMH and euploidy rate (P = 0.02) was demonstrated. Clinical outcome was similar, including biochemical, clinical and ongoing pregnancy rates as well as pregnancy loss. This study shows a correlation between AMH and aneuploidy rate, specifically among infertile patients younger than 37 years old. Study limitations are discussed.

The myths surrounding mild stimulation in vitro fertilization (IVF)

So-called mild controlled ovarian hyperstimulation (mCOH) has in recent years increased in popularity, claiming to be safer and more patient-friendly, while also improving in vitro fertilization (IVF) outcomes. We here challenge the International Society for Mild Approaches in Assisted Reproduction (ISMAAR) definition of mild stimulation, and especially address four fundamental issues, where our review found conventional COH (cCOH) advantageous over mCOH. They are: prevalence of severe ovarian hyperstimulation syndrome (OHSS), oocyte/embryo quality, pregnancy/live birth rates, and cost. We conclude that an objective review of the literature does not support the routine utilization of mCOH in assisted reproduction.

A Higher Ovarian Response after Stimulation for IVF Is Related to a Higher Number of Euploid Embryos

This study has analysed the relationship between ovarian response and the number of euploid embryos. This is a post hoc analysis of a subset of data generated during a prospective cohort study previously published. Forty-six oocyte donors were subjected to ovarian stimulation with 150 IU of rFSH and 75 IU of hp-hMG in a GnRH agonist long protocol. Preimplantation genetic screening was performed in all viable embryos. We observed a positive relationship between ovarian response and the number of euploid embryos. When ovarian response was above the median (≥17 oocytes), the mean number of euploid embryos per donor was 5.0 ± 2.4, while when <17 oocytes were obtained the mean number of euploid embryos was 2.7 ± 1.4 (p = 0.000). Aneuploidy rate did not increase with ovarian response or gonadotropin doses. Also, the number of euploid embryos was inversely related to the amount of gonadotropins needed per oocyte obtained (ovarian sensitivity index). These results suggest that the number of euploid embryos available for embryo transfer increases as the number of oocytes obtained does. Considering the total number of euploid embryos seems more relevant than the aneuploidy rate.

Regimen of ovarian stimulation affects oocyte and therefore embryo quality

Without any doubt the regimen used to mature multiple capable oocytes for IVF impacts IVF outcomes. Studies have indicated that the inclusion of LH activity, adjuvant agents such as growth hormone (GH), and regimens providing for simultaneous action of both LH and FSH during final oocyte maturation may have beneficial effects on IVF outcomes. Because of the difficulty in improving IVF outcomes in poor responders, the studies on GH are of particular interest. As pointed out in this review, the apparent beneficial effects of GH on oocyte competence may also apply to older women or to normal responders with reduced embryo quality. A much more difficult question is whether and how much ovarian stimulation impacts on oocyte competence. Paradoxically it seems that there are not demonstrated differences between the stimulated and the natural unstimulated cycle, whereas studies in laboratory animals and IVF patients have shown deleterious effects of higher compared with lower doses of gonadotropins. Recent studies suggest that the use of high doses of gonadotropins as an independent factor correlates negatively with the probability of live birth, whereas a high ovarian response per se is associated with better cumulative pregnancy rates, owing to the availability of more euploid and good-quality embryos. Although adjunctive use of androgens has not been discussed here, it is briefly covered in the first review of this series.

The "graying" of infertility services: an impending revolution nobody is ready for

BACKGROUND

As demand for infertility services by older women continues to grow, because achievable in vitro fertilization (IVF) outcomes are widely underestimated, most fertility centers do not offer maximal treatment options with use of autologous oocytes. Limited data suggest that clinical IVF outcomes in excess of what the American Society for Reproductive Medicine (ASRM) considers "futile" can, likely, be achieved up to at least age 45 years.

METHODS

In an attempt to point out an evolving demographic trend in IVF, we here report our center's IVF data for 2010-2012 and national U.S. data for 1997-2010. Though our center's data are representative of only one IVF center's patients, they, likely, are unique since they probably represent the most adversely selected IVF patient population ever reported and, thus, are predictive of future demographic trends. In addition we performed a systematic review of the literature on the subject based on PubMed, Medline and Google Scholar searches till year-end 2013. The literature search was performed using key words and phrases relevant to fertility treatments in older women.

RESULTS

As demonstrated by our center's patient demographics and national U.S. data, IVF centers are destined to treat increasingly adversely selected patients. Despite our center's already extremely adversely selected patient population, age-specific IVF cycle outcomes in women above age 40 years, nevertheless, exceeded criteria for "futility" by the ASRM and widely quoted outcome expectations in the literature for patient ages. Age 43 discriminates between better and poorer clinical pregnancy and live birth rates.

CONCLUSIONS

"Graying" of the infertility populations in the developed world, a problem with potentially far-reaching medical and societal consequences, has so far been only insufficiently addressed in the literature. As women's postmenopausal life spans already exceed postmenarcheal life spans at the start of the 20th century, the "graying" of infertility services can be expected to further accelerate, no longer as in recent decades bringing only women in their 40s into maternity wards but also women in their 50s and 60s. Medicine and society better get ready for this revolution.

Preimplantation genetic screening (PGS) still in search of a clinical application: a systematic review

Only a few years ago the American Society of Assisted Reproductive Medicine (ASRM), the European Society for Human Reproduction and Embryology (ESHRE) and the British Fertility Society declared preimplantation genetic screening (PGS#1) ineffective in improving in vitro fertilization (IVF) pregnancy rates and in reducing miscarriage rates. A presumably upgraded form of the procedure (PGS#2) has recently been reintroduced, and is here assessed in a systematic review. PGS#2 in comparison to PGS#1 is characterized by: (i) trophectoderm biopsy on day 5/6 embryos in place of day-3 embryo biopsy; and (ii) fluorescence in-situ hybridization (FISH) of limited chromosome numbers is replaced by techniques, allowing aneuploidy assessments of all 24 chromosome pairs. Reviewing the literature, we were unable to identify properly conducted prospective clinical trials in which IVF outcomes were assessed based on "intent to treat". Whether PGS#2 improves IVF outcomes can, therefore, not be determined. Reassessments of data, alleged to support the efficacy of PGS#2, indeed, suggest the opposite. Like with PGS#1, the introduction of PGS#2 into unrestricted IVF practice again appears premature, and threatens to repeat the PGS#1 experience, when thousands of women experienced reductions in IVF pregnancy chances, while expecting improvements. PGS#2 is an unproven and still experimental procedure, which, until evidence suggests otherwise, should only be offered under study conditions, and with appropriate informed consents.

Does the number of oocytes retrieved influence pregnancy after fresh embryo transfer?

Background

The nature of the association between the number of oocytes retrieved and in vitro fertilization (IVF) outcomes after fresh embryo transfer remains unclear because of conflicting results reported in the studies on this subject. In addition, the influence of the quality of the embryos transferred is usually neglected. The objective of this study is to assess the relationships of the number of oocytes retrieved, the number and quality of embryos transferred, and the prospects of pregnancy after fresh embryo transfer.

Methods

The data on 3131 infertile women undergoing their first IVF treatment cycle between January 2009 and December 2010 were collected retrospectively. Restricted cubic splines and stratified analyses were used to explore the relationships between the number of oocytes retrieved, the number and quality of embryos transferred, and the IVF outcomes.

Results

When stratified by the number and quality of transferred embryos, no significant differences in the chances for clinical pregnancy and live birth were found in three groups of oocytes yielded (≤6, 7–14, or ≥15). The relationship between the number of oocytes retrieved and pregnancy is nearly a reflection of the pattern of the relationship between the number of oocytes retrieved and the probability of having two good-quality embryos transferred. The patients with the “optimal” number of oocytes were not only younger but also had the highest probability of having two good-quality embryos replaced.

Conclusions

Similarly aged patients have similar pregnancy prospects after fresh embryo transfer when the same number and quality of embryos are replaced, irrespective of their number of oocytes. Selecting the desired number of good-quality embryos for transfer is the key to IVF success. Thus, aiming at retrieving an optimal number of oocytes to maximize IVF outcomes in a fresh cycle could place undue stress on the patients and may not be the best medical decision.

A review of, and commentary on, the ongoing second clinical introduction of preimplantation genetic screening (PGS) to routine IVF practice

PURPOSE

Current re-introduction of "improved" preimplantation genetic screening (PGS#2) raises the question whether PGS#2 is ready for routine clinical application.

METHODS

We assessed available evidence via review of published data for years 2005-2012, and review of currently ongoing registered clinical trials, based on searches under appropriate key words in PubMed, MEDLINE, Cochrane Database System Review and Google Scholar and http://www.ClinicalTrials.gov . In absence of prospective clinical trials, and due to limited available data, individual publications/ongoing studies are assessed.

RESULTS

PGS#2 offers significant improvements in accuracy of aneuploidy diagnosis over PGS#1. By moving embryo biopsy from day-3 after fertilization (6-8 cell stage) to trophectoderm biopsy at blastocyst stage (day 5-6), PGS#2, however, adds additional co-variables to the analysis of efficacy of the procedure, which have special relevance for women with diminished ovarian reserve (DOR), who usually produce small egg and embryo numbers. Limited published data, claiming efficacy of PGS#2, as well as ongoing clinical trials, do not consider these additional co-variables, do not analyze outcomes by intent to treat and, therefore, have to be considered biased in patient selection.

CONCLUSIONS

Here reached conclusions are based on absence of adequate data rather than affirmative outcome assessments. They, therefore, are subject to change at any future date with generation of significant new data. Premature introduction of PGS#1 caused significant damage to patients. As currently no reliable PGS#2 data are available to suggest improvements in IVF outcomes, to avoid a repeat of the PGS#1 experience, PGS#2 should be considered experimental until data show otherwise.