Harnessing Artificial Intelligence to Predict Ovarian Stimulation Outcomes in In Vitro Fertilization: Scoping Review

BACKGROUND

In the realm of in vitro fertilization (IVF), artificial intelligence (AI) models serve as invaluable tools for clinicians, offering predictive insights into ovarian stimulation outcomes. Predicting and understanding a patient's response to ovarian stimulation can help in personalizing doses of drugs, preventing adverse outcomes (eg, hyperstimulation), and improving the likelihood of successful fertilization and pregnancy. Given the pivotal role of accurate predictions in IVF procedures, it becomes important to investigate the landscape of AI models that are being used to predict the outcomes of ovarian stimulation.

OBJECTIVE

The objective of this review is to comprehensively examine the literature to explore the characteristics of AI models used for predicting ovarian stimulation outcomes in the context of IVF.

METHODS

A total of 6 electronic databases were searched for peer-reviewed literature published before August 2023, using the concepts of IVF and AI, along with their related terms. Records were independently screened by 2 reviewers against the eligibility criteria. The extracted data were then consolidated and presented through narrative synthesis.

RESULTS

Upon reviewing 1348 articles, 30 met the predetermined inclusion criteria. The literature primarily focused on the number of oocytes retrieved as the main predicted outcome. Microscopy images stood out as the primary ground truth reference. The reviewed studies also highlighted that the most frequently adopted stimulation protocol was the gonadotropin-releasing hormone (GnRH) antagonist. In terms of using trigger medication, human chorionic gonadotropin (hCG) was the most commonly selected option. Among the machine learning techniques, the favored choice was the support vector machine. As for the validation of AI algorithms, the hold-out cross-validation method was the most prevalent. The area under the curve was highlighted as the primary evaluation metric. The literature exhibited a wide variation in the number of features used for AI algorithm development, ranging from 2 to 28,054 features. Data were mostly sourced from patient demographics, followed by laboratory data, specifically hormonal levels. Notably, the vast majority of studies were restricted to a single infertility clinic and exclusively relied on nonpublic data sets.

CONCLUSIONS

These insights highlight an urgent need to diversify data sources and explore varied AI techniques for improved prediction accuracy and generalizability of AI models for the prediction of ovarian stimulation outcomes. Future research should prioritize multiclinic collaborations and consider leveraging public data sets, aiming for more precise AI-driven predictions that ultimately boost patient care and IVF success rates.

Stain-free enucleation of mouse and human oocytes with a 1033 nm femtosecond laser

Significance

Preparation of a recipient cytoplast by oocyte enucleation is an essential task for animal cloning and assisted reproductive technologies in humans. The femtosecond laser is a precise and low-invasive tool for oocyte enucleation, and it should be an appropriate alternative to traditional enucleation by a microneedle aspiration. However, until recently, the laser enucleation was performed only with applying a fluorescent dye.

Aim

This work is aimed to (1) achieve femtosecond laser oocyte enucleation without applying a fluorescent dye and (2) to study the effect of laser destruction of chromosomes on the structure and dynamics of the spindle.

Approach

We applied polarized light microscopy for spindle visualization and performed stain-free mouse and human oocyte enucleation with a 1033 nm femtosecond laser. Also, we studied transformation of a spindle after metaphase plate elimination by a confocal microscopy.

Results

We demonstrated a fundamental possibility of inactivating the metaphase plate in mouse and human oocytes by 1033 nm femtosecond laser radiation without applying a fluorescent dye. Irradiation of the spindle area, visualized by polarized light microscopy, resulted in partly or complete metaphase plate destruction but avoided the microtubules impairment. After the metaphase plate elimination, the spindle reorganized, however, it was not a complete depolymerization.

Conclusions

This method of recipient cytoplast preparation is expected to be useful for animal cloning and assisted reproductive technologies.

Predictive value of cytoplasmic granulation patterns during in vitro fertilization in metaphase II oocytes: Part I, poor-prognosis patients

OBJECTIVE

To determine whether 4 cytoplasmic granulation patterns of human metaphase II oocytes have a predictive value for in vitro fertilization outcomes.

DESIGN

A retrospective cohort study.

SETTING

An academically affiliated private clinical infertility and research center.

PATIENT(S)

A total of 2,690 consecutive fresh autologous oocytes collected from women aged 41.2 ± 5.0 years between 2017 and 2019.

INTERVENTION(S)

Determination of granulation pattern in every oocyte during intracytoplasmic sperm injection as fine, central, dispersed, and newly introduced uneven granulations.

MAIN OUTCOME MEASURE(S)

Fertilization outcomes (2 pronuclei [2PN], <2PN, and >2PN rates), pregnancy, and live birth rates for different granulation patterns at different ages.

RESULT(S)

Fine granulation produced the highest 2PN rate, followed by central, uneven, and dispersed granulation (91.8%, 83.9%, 77.9%, and 54.8%, respectively). Differences in fertilization were surprisingly relatively independent of age and other variables. Overall, compared with fine granulation, dispersed granulation resulted in lower pregnancy rates (4.6% vs. 10.7%) and known-outcome analysis (1.3% vs. 5.6%) as well as lower live birth rates (3.0% vs. 8.9%) and known-outcome analysis (0.6% vs. 5.6%). The known-outcome analysis demonstrated that uneven granulation had lower live birth rates than fine granulation (2.3% vs. 5.6%). Unexpectedly, the ooplasm granulation patterns were largely disassociated from embryo morphologic grades.

CONCLUSION(S)

We, for the first time, demonstrated that 4 distinct cytoplasmic granulation patterns in metaphase II oocytes had, largely independent of age and other variables, a predictive value for fertilization, pregnancy, and live birth outcomes in in vitro fertilization cycles of poor-prognosis patients. These data suggest that upstream ooplasm granulation patterns deserve closer attention in terms of embryo selection.

Does the meiotic spindle really predicts embryo implantation and live birth rates? An update

SummaryThe aim of this study was to determine the capacity of the meiotic spindle (MS) to predict embryo implantation and live birth rates. For this purpose, we performed a broad systematic literature search. Of all publications retrieved, only those in which the implantation rates were related to some characteristics of the MS were evaluated. Despite the different methodology used in all the chosen studies, presence of the MS in oocytes was found to be positively associated with embryo implantation. Moreover, high retardance values, as well as strict criteria of normality in the MS structure, are significantly related to higher embryo implantation numbers and live birth rates.

Predictive value of spindle retardance in embryo implantation rate

PURPOSE

We evaluated the relationship between meiotic spindle characteristics and in vitro fertilization cycle outcome.

METHODS

Five hundred sixty-nine oocytes from 86 in vitro fertilization cycles were analyzed for fertilization and subsequent implantation rates. Oocytes were assessed for maturation status. The oocytes and embryos were cultured in sequential and nonsequential media (G Series, Vitrolife, Sweden) and incubated in 6% CO₂, 5% O₂ at 37 °C. Two hours following oocyte decumulation (38-39 h post-hCG/GnRH administration) and prior to microinjection, the structure of the meiotic spindle was assessed using the Oosight Imaging System (CRI, UK).

RESULTS

Four hundred fifty-six oocytes (80.5%) had a visible meiotic spindle, 82 (14.7%) had no meiotic spindle, and 31 (5.5%) were in telophase I. Oocytes exhibiting a meiotic spindle had a significantly higher fertilization rate and a lower rate of abnormal fertilization. Implantation data were obtained for 195 of the embryos transferred. The implantation rate for embryos derived from oocytes with a meiotic spindle was 32.9%, while in embryos originating from oocytes without a meiotic spindle and oocytes in telophase, this value dropped significantly (8.8 and 0%, respectively). To determine the correlation between retardance values and implantation rate for each oocyte, we established four groups, finding a range of retardance values with significantly higher implantation rates (27.5, 21, 29.3, and 53.8%, respectively).

CONCLUSION

Meiotic spindle imaging may be a valuable tool for prediction of oocyte quality, and retardance values of meiotic spindles, together with classical morphological classification, can be useful to select embryos with a higher implantation potential.

Relationship between pre-ICSI meiotic spindle angle, ovarian reserve, gonadotropin stimulation, and pregnancy outcomes

PURPOSE

The goals of this study are to analyze the clinical pregnancy rate as a function of the pre-intracytoplasmic sperm injection (ICSI) oocyte spindle angle and determine factors which can be associated with different spindle angles, if clinically relevant.

METHODS

Fifty-eight patients, who underwent their first ICSI cycle from January to December 2013, were included. Eight hundred thirty oocytes were collected, and 648 were metaphase II (MII) on retrieval day. Spindles were characterized in terms of visibility and position in relation to the first polar body (PB). Oocytes were separated into four groups based on angle: (group 1, n = 297) 0°-29°; (group 2 n = 212) 30°-89°; (group 3, n = 72) ≥90°; and those with no visible spindle (group 4, n = 67).

RESULTS

The rate of blastocyst development was associated with the spindle angle (p = 0.002). The rate of good quality blastocysts were as follows: group 1 (42%), group 2 (30%), group 3 (35%), and group 4 (19%) (p = 0.02). Pregnancy and live birth rates were also affected (p = 0.007 and p = 0.046, respectively). Antral follicle count (AFC) (p = 0.001), total FSH stimulating dose (p = 0.0001), and peak serum estradiol level (p = 0.0001) were associated with spindle angle grouping. Miscarriage rates trended different (p = 0.07). On the other hand, day 3 follicle-stimulating hormone (FSH) levels and female and male age were not associated with spindle angle grouping.

CONCLUSIONS

Embryos resulting from oocytes with pre-ICSI spindle angles between 0° and 29° were associated with better blastocyst, pregnancy, live birth, and miscarriage rates when compared to oocytes that had no visible spindle. Low ovarian reserve and excessive stimulation were also associated with lack of spindle and therefore lower pregnancy outcomes.

Optimal polar bodies angle for higher subsequent embryo viability: a pilot study

OBJECTIVE

To determine the optimal polar bodies (PB) angle for higher subsequent embryo implantation potential.

DESIGN

Prospective study.

SETTING

Academic fertility center.

PATIENT(S)

From January to July 2015, 116 patients were recruited in their first IVF-ET cycles.

INTERVENTION(S)

At the pronuclear stage, PB angle was measured with the use of E-ruler 1.1.

MAIN OUTCOME MEASURE(S)

The primary outcome measure was good-quality embryo rate. Secondary measures were clinical pregnancy rate (CPR) and embryo implantation rate (IR).

RESULT(S)

A total of 1,103 oocytes were retrieved. PB angle was measured in 454 zygotes, and 164 of their subsequent embryos were transferred into the uterus. All-or-none implantation took place in 129 embryos, and 89 patients accepted fresh embryo(s) transfer with known PB angle. By means of receiver operating characteristic analysis, the optimal PB angle for subsequent embryo implantation was 24.25°. Based on this cutoff value, 454 zygotes were divided into two groups: small-angle and large-angle. A higher percentage of small-angle zygotes developed into good-quality embryos (70.97% vs. 58.58%). CPR and IR both decreased progressively from purely small-angle embryos to mixed embryos to purely large-angle embryos (CPR: 72.41% vs. 38.46% vs. 26.47%, respectively; IR: 63.27% vs. 26.92% vs. 16.67%, respectively).

CONCLUSION(S)

Noninvasive assessment of PB angle is a viable technique for zygote selection and should be included in embryo selection parameters.

CLINICAL TRIAL REGISTRATION NUMBER

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR-OOC-15005882.

Oocyte environment: follicular fluid and cumulus cells are critical for oocyte health

Bidirectional somatic cell-oocyte signaling is essential to create a changing intrafollicular microenvironment that controls primordial follicle growth into a cohort of growing follicles, from which one antral follicle is selected to ovulate a healthy oocyte. Such intercellular communications allow the oocyte to determine its own fate by influencing the intrafollicular microenvironment, which in turn provides the necessary cellular functions for oocyte developmental competence, which is defined as the ability of the oocyte to complete meiosis and undergo fertilization, embryogenesis, and term development. These coordinated somatic cell-oocyte interactions attempt to balance cellular metabolism with energy requirements during folliculogenesis, including changing energy utilization during meiotic resumption. If these cellular mechanisms are perturbed by metabolic disease and/or maternal aging, molecular damage of the oocyte can alter macromolecules, induce mitochondrial mutations, and reduce adenosine triphosphate production, all of which can harm the oocyte. Recent technologies are now exploring transcriptional, translational, and post-translational events within the human follicle with the goal of identifying biomarkers that reliably predict oocyte quality in the clinical setting.

The impact of examining the meiotic spindle by polarization microscopy on assisted reproduction outcomes

OBJECTIVE

To examine the effect of submitting oocytes to polarization microscopy (PM) before intracytoplasmic sperm injection (ICSI).

DESIGN

Retrospective observational study.

SETTING

University hospital in Brazil.

PATIENT(S)

Couples undergoing ICSI.

INTERVENTION(S)

PM before ICSI (PM group) compared with no PM before ICSI (No-PM group)

MAIN OUTCOMES MEASURE(S)

Fertilization and cleavage rates, formation of top-quality embryos (TQEs), and implantation, clinical pregnancy, miscarriage, and live-birth rates.

RESULT(S)

The PM group consisted of 1,000 consecutive oocytes from 201 couples submitted to PM during the year of 2008. The No-PM group consisted of 1,400 oocytes from 249 couples: 700 consecutive oocytes were retrieved before we started using PM and 700 consecutive oocytes were retrieved after we stopped using PM. In the PM group, we observed an increased fertilization rate (79.7% vs. 72.5%, PM group vs. No-PM group, respectively) but reduced cleavage rate (86.2% vs. 92.5%) and TQE formation (33.1% vs. 49.9%). Implantation (18.7% vs. 20.6%), clinical pregnancy (31.8% vs. 33.3%), miscarriage (21.9% vs. 15.7%), and live-birth (24.9% vs. 28.1%) rates were not significantly different between groups.

CONCLUSION(S)

Use of PM was associated with increased fertilization rate but reduced cleavage rate and TQE formation; no significant difference was observed for implantation, clinical pregnancy, or live-birth rates.

Culture systems: physiological and environmental factors that can affect the outcome of human ART

Many aspects of the embryo culture environment have been shown to affect embryo development and the subsequent outcomes of human ART. It is now becoming increasingly evident that embryo and later development can be affected by events and conditions that occur before, perhaps long before, the oocytes and sperm are collected and brought together in the ART laboratory. These include diet and metabolic disorders, general health and disease, physical and psychological stress, exposure to environmental estrogens and other toxins, pharmaceuticals, alcohol, smoking, and drug abuse. This paper discusses the known and potential effects of season of the year (or temperature) and environmental air pollution on the outcomes of human ART. It may be useful to advise ART patients to avoid high environmental temperature and air pollution. In addition, it is important for clinical embryologists to recognize that adverse outcomes may result from such exposures, and to incorporate this into the analysis of clinic data for the purposes of quality management.

Relevance and Methodology for the Morphological Analysis of Oocyte Quality in IVF and ICSI

Oocytes collected from patients following ovarian stimulation exhibit varying qualities. The quality of oocytes has an effect on its subsequent fertilization, developmental competence post-fertilization and the viability of resultant embryos. The aim of this article was to review the morphological criteria devised for assessment of oocyte quality by ordinary light and polarized light microscopy before IVF or ICSI. The parameters employed in the evaluation of oocyte morphology include the appearance of: structure of the cumulus–oocyte complex, oocyte cytoplasm, perivitelline space, zona pellucida, polar body and meiotic spindle.