Enhancing In Vitro Fertilization Outcomes in Advanced Maternal Age

INTRODUCTION Enhancing in vitro fertilization (IVF) outcomes for women of advanced maternal age (AMA) is a significant focus in reproductive medicine. While the primary challenge is the age-related decline in oocyte quality and quantity, various strategies and adjunctive therapies have been studied to improve success rates. It is important to note that the effectiveness of these strategies can vary and what works for one person may not work for another. A personalized approach, guided by a fertility specialist, is important. Based on the references to relevant studies and research, there are some of the key strategies and treatments as below: CORE CHALLENGES OF ADVANCED MATERNAL AGE AND TRENDS IN TAIWAN Taiwan exhibits one of the most drastic trends of delayed childbearing globally. The mean maternal age at first birth has steadily increased, from 28.0 years (early 2000s) to over 32 years in recent years. The proportion of births to women aged 35 years or older has sharply risen, exceeding 30% of all births. Taiwan has one of the world’s lowest total fertility rates, consistently below 1.3 and reaching a historical low of around 0.97 in 2021.[1] Taiwan became an aged society in 2018 and is projected to become a “super-aged society” soon. IVF success rates in Taiwan, like worldwide, show a stark decline with age, highlighting the physiological challenge. Live birth rate per embryo transfer (ET) for women <35 years is around 50%. Live birth rate per ET for women more than 40 years is about 18.7%.[2] The Taiwanese government has implemented significant pronatalist policies to combat the low birth rate, with a focus on supporting IVF. Since 2021, the government offers substantial financial subsidies for IVF treatments, available to all infertile married couples where the wife is under 45 years old. The number of subsidized attempts is higher for women under 39 (up to 6 attempts) than for those 40–44 (up to 3 attempts). These subsidies encourage single ET (SET) by tying higher success rates to the number of embryos transferred, aiming to reduce the multiple birth rate associated with IVF. THE STRATEGIES TO TREAT ADVANCED MATERNAL AGE ININ VITRO FERTILIZATION–PRE-IN VITRO FERTILIZATION ASSESSMENT The baseline assessment is introduced including measuring anti-Müllerian hormone (AMH), antral follicle count, and follicle-stimulating hormone (FSH).[3] To evaluate the appearance of ovary, fallopian tube, and uterus and to assess the partner semen analysis. These data from the baseline assessment will guide the protocol choice and prognosis.[4,5] Based on the pre-IVF assessment, several strategic decisions are made. With reduced ovarian reserve, need more aggressive stimulation; but also balance with risk. Furthermore, choosing protocols (Gonadotropin-releasing hormone (GnRH) antagonist vs. agonist) tailored.[6] Since competence declines, more oocytes gives better chances; cumulative live birth rate (fresh + frozen ETs [FETs]) depends on number retrieved.[6] If reserve is low, do not delay. Furthermore, preemptive fertility preservation (oocyte or embryo cryopreservation) if age getting high or before treatments that might further reduce fertility. If many embryos, to select euploid ones, reduce miscarriage, improve implantation efficiency. Blastocyst biopsy and comprehensive chromosome screening seems to give better results than older methods.[7] THE STRATEGIES TO TREAT ADVANCED MATERNAL AGE ININ VITRO FERTILIZATION – OVARIAN STIMULATION Enhancing IVF outcomes for women of AMA through ovarian stimulation is a key area of research. While no strategy can reverse the biological effects of aging on egg quality, certain protocols and adjuvant therapies aim to maximize the number and quality of retrieved eggs. Traditional IVF protocols use high doses of gonadotropins to stimulate the growth of as many follicles as possible. However, in women with a diminished ovarian reserve, a common issue with AMA, this approach may not yield better results and can increase the risk of side effects.[8,9] A growing body of evidence suggests that mild stimulation protocols, which use lower doses of hormones, may be just as effective as conventional protocols for women with poor ovarian reserve, leading to similar pregnancy rates. These protocols are often associated with less cost and discomfort for the patient.[10] Use higher starting doses for those with reduced reserve or known poor responders, however, avoiding exceeding doses that are unlikely to yield benefit. Literature suggests that beyond certain FSH/luteinizing hormone (LH) daily dose thresholds (often 300–375 IU FSH + ~75–150 IU LH) may be diminishing returns.[6] Use LH activity (either recombinant LH or human menopausal gonadotropin) especially in cycles where AMH is low or previous responses have been poor. Recombinant human luteinizing hormone (r-hLH) improves oocyte yield and pregnancy rates in AMA and hypo-responders.[6] The rationale of adding LH are boosting FSH sensitivity by upregulates FSH receptors in granulosa cells,[11] supporting estrogen synthesis and follicle growth by stimulating androgen production[6] and improving follicular environment and oocyte quality, especially in aging ovaries.[11] THE STRATEGIES TO TREAT ADVANCED MATERNAL AGE ININ VITRO FERTILIZATION – LABORATORY To understand which interventions may help, it is useful to review what goes wrong in older oocytes/embryos including increased aneuploidy rates (meiotic errors and spindle defects),[6] mitochondrial dysfunction, reduced mitochondrial number or quality,[12] oxidative stress and reactive oxygen species damage,[12] slower or abnormal embryo morphokinetics,[13] and reduced ovarian reserve (fewer available oocytes/embryos).[14] Given these challenges, the goal in the laboratory is to maximize the quality of what is available: Better selection, better culture, minimizing damage, maybe some rescue/augmentation. Extended embryo culture to blastocyst stage is a strategy often employed in AMA. This allows for a more rigorous natural selection process, as chromosomally abnormal embryos are less likely to progress to the blastocyst stage. This can decrease the number of ineffective ETs.[15] Screening embryos (blastocyst stage trophectoderm biopsy and comprehensive chromosome screening) to select euploid embryos. This reduces miscarriage, improves implantation for older women whose embryo pool has high aneuploidy.[7] Maintaining optimal air quality by controlling volatile organic compounds, microbes, and chemically active compounds using high-efficiency filtration systems (like high-efficiency particulate air (HEPA) and activated carbon filters, sometimes combined with advanced purification systems) has been shown to improve overall IVF outcomes, which is critical for the often more fragile embryos from AMA patients.[15] Continuous monitoring of embryo development can provide additional noninvasive data on embryo viability (morphokinetics). While early parameters may not be unique to AMA, observing developmental arrest (which is more common in AMA) can aid in selection.[13] Experimental strategies such as supplementing mitochondria (donor or autologous), spindle transfer, and pronuclear transfer are applied to try to overcome cytoplasmic/mitochondrial deficits or defective meiotic spindle function in older oocytes.[6] However, these experimental strategies as future strategies mean that AMA in IVF is still a challenge. THE STRATEGIES TO TREAT ADVANCED MATERNAL AGE ININ VITRO FERTILIZATION – FROZEN VERSUS FRESH The choice between fresh and FET to enhance IVF outcomes in women of AMA is complex, with research offering mixed findings and suggesting that the best approach often depends on individual patient factors. The factors for supporting FET include the rationale for FET is that the ovarian stimulation drugs used to retrieve eggs can create supraphysiologic hormone levels that may negatively affect the endometrial receptivity. Freezing allows a delay until the uterine lining is prepared in a more natural or hormonally optimized cycle[16] and some studies indicate that FET may be associated with a lower risk of preterm birth and low birth weight compared to fresh ET,[17] and allowing preimplantation genetic testing for aneuploidy (PGT-A) to screen embryos for chromosomal abnormalities (aneuploidy), which are much more common in AMA. PGT-A requires the embryos to be biopsied and then frozen while awaiting results, making FET a necessary step. Using chromosomally normal (euploid) embryos significantly increases implantation and live birth rates and decreases miscarriage rates, especially in AMA patients.[18] THE STRATEGIES TO TREAT ADVANCED MATERNAL AGE ININ VITRO FERTILIZATION – PREIMPLANTATION GENETIC TESTING UTILIZATION PGT-A is a key strategy used to enhance IVF outcomes, particularly in AMA women, generally considered to be 35 years or older. The primary benefit of PGT-A in this demographic stems from the high rate of chromosomal abnormalities (aneuploidy) in embryos, which significantly increases with maternal age.[18] By using PGT-A, IVF outcomes are enhanced by identifying euploid embryos. PGT-A screens embryos for the correct number of chromosomes (euploid). Since the risk of aneuploidy rises significantly with age (from about 25% under age 35 years to potentially over 75% past age 40 years),[18] PGT-A allows clinicians to prioritize the transfer of only chromosomally normal embryos. Transferring a euploid embryo significantly increases the chance of successful implantation, as chromosomal abnormalities are a leading cause of implantation failure. Studies suggest that when a euploid embryo is transferred, the pregnancy success rate is often similar to that of younger women.[19] By avoiding the transfer of aneuploid embryos, which would likely fail, PGT-A can reduce the number of unsuccessful cycles, leading to a faster path to a live birth.[18] The majority of miscarriages, especially in older women, are caused by embryonic aneuploidy. By transferring a euploid embryo, PGT-A has been shown to significantly reduce the risk of miscarriage compared to transferring an untested embryo.[19] PGT-A helps to reduce the risk of conceiving a baby with a genetic condition due to a chromosomal abnormality (e.g., Down syndrome and Trisomy 18) that is more common in offspring of older mothers. With the confidence that an embryo is chromosomally normal, PGT-A encourages the practice of transferring only one embryo (elective SET), which minimizes the risk of multiple pregnancies (twins and triplets), a major health risk for both the mother and the babies. However, even though PGT-A has benefits, especially in AMA, it is not magic. There are only a few cells (often from trophectoderm) in a biopsy samples. The embryo might have a mix of normal and abnormal cells. Some embryos labeled aneuploid or mosaic may still lead to healthy pregnancies. False positives can lead to discarding viable embryos. Because many embryos will be tested and found abnormal or mosaic, the absolute number of embryos you can transfer may decrease. PGT-A adds cost, lab work, possibly cryopreservation, and time. It may mean waiting until results are ready or freezing embryos until transfer. If few embryos develop to blastocyst stage, or if embryo quality is poor, PGT-A might not improve chances per retrieval; it helps more per transfer of euploid embryo. Deciding what to do with “non-viable” embryos, mosaic ones, etc., can have emotional cost. Some may worry about discarding embryos. However, PGT-A is most helpful when we have several embryos to choose from. If there are very few embryos (e.g., only 1–2 blastocysts) in AMA, testing them may not improve your chance of a baby – and could even prevent a transfer if they are tested abnormal. We might alternatively consider transferring the best-quality embryo directly instead of PGT-A. Therefore, the suggestion for AMA with few embryos is that PGT-A could be discussed as an optional tool to avoid transferring aneuploidy embryos, but only if the patient accepts the possibility of no transfer. If embryos are good quality and patient wants every chance for transfer, the fresh or frozen transfer without PGT-A is often favored. THE STRATEGIES TO TREAT ADVANCED MATERNAL AGE ININ VITRO FERTILIZATION – LUTEAL PHASE SUPPORT Progesterone is the foundation of luteal phase support (LPS); adequacy of serum progesterone matters for clinical outcomes. When luteal function is further compromised (e.g., after GnRH-agonist trigger, poor ovarian response (POR) common in AMA), consider modified LPS (higher or combined progesterone routes, earlier start, or luteal adjuvants such as low-dose human chorionic gonadotropin [hCG] or GnRH-agonist boluses).[20] Individualized serum progesterone measurement during the luteal phase (and on day of ET in hormone replacement therapy [HRT]/FET cycles) and adjust route/dose if levels are suboptimal.[21] Use a reliable progesterone route (vaginal micronized progesterone is commonly used and effective). If concern for absorption or prior low serum P, add or use an alternative/combined route (intramuscular (IM) or subcutaneous [SC] progesterone). SC progesterone is an evidence-supported alternative to IM/vaginal routes.[22] Studies show low serum progesterone on the day of ET (or in the mid-luteal phase) is associated with worse outcomes; a commonly cited threshold in HRT/FET cycles is 10 ng/mL (study-dependent). Monitoring allows dose/route adjustment.[21] GnRH antagonist protocol commonly causes luteolysis; therefore, options to rescue the luteal phase include intensive steroid supplementation or giving low-dose hCG (or dual trigger strategies). In AMA patients where embryo numbers are already low, pick a luteal rescue that preserves pregnancy chances. Because AMA patients often have poorer embryo competence, minimizing endometrial/luteal failure is critical. Therefore, some opinions suggest that starting LPS early (oocyte pick-up evening), using a robust route or dual routes (vaginal + SC/IM) and continue LPS until fetal cardiac activity (or 8–12 weeks in some practices).[22] Evidence for prolonged duration is not definitive, but clinicians often extend support in AMA. Small randomized controlled trials (RCTs)/series show potential benefit of adding GnRH-agonist boluses in GnRH antagonist cycles or low-dose hCG as luteal rescue after GnRHa trigger – but these have heterogeneity considerations. Estradiol addition has mixed evidence. Therefore, applying adjuvants for LPS should be used selectively such as prior luteal insufficiency, repeated implantation failure, or GnRHa triggering.[23] THE STRATEGIES TO TREAT ADVANCED MATERNAL AGE ININ VITRO FERTILIZATION – FUTURE PERSPECTIVES The most promising future strategies for treating AMA in IVF focus on addressing the two primary age-related challenges: Low oocyte quantity (ovarian reserve) and poor oocyte quality (aneuploidy). We make clearer separation of what is experimental/early stage and clinically applicable in the near future. THE CLINICALLY APPLICABLE IN THE NEAR FUTURE Mitochondrial dysfunction and mtDNA defects accumulate with age and impair oocyte energy metabolism; replenishing mitochondria or improving mitochondrial function may raise oocyte/embryo competence. Heterologous mitochondrial replacement techniques (spindle transfer and pronuclear transfer), autologous mitochondrial enrichment or transfer, and small-molecule mitochondrial enhancers are being reported in small series,[24-26] but results are mixed and ethically regulated in many countries. Awakening dormant primordial follicles or improving the intra-ovarian niche could increase follicle recruitment in women with diminished reserve. Intra-ovarian platelet-rich plasma (PRP) injections, drug-based or “drug-free” in vitro activation (IVA) of ovarian tissue with autotransplantation, and surgical activation techniques have been reported in small studies.[27-30] Growing number of observational studies and meta-analyses suggest that PRP may improve ovarian markers and occasional pregnancy in POR/primary ovarian insufficiency patients, IVA has produced case reports/series of pregnancies, still early and heterogeneous; randomized data are limited. The better embryo selection that nondestructively identifies embryos with highest implantation potential (and/or euploidy) could improve live births per transfer in AMA. Deep-learning models on time-lapse imaging, combined morphology metabolomics, cell-free DNA from spent media (non-invasive PGT), and AI clinical data fusion will be applied to address the goal.[31,32] The promising trials and commercial tools showing improved predictive accuracy; noninvasive PGT and AI models are under validation and will likely refine embryo prioritization. Implantation is a function of both embryo and endometrium; AMA may affect endometrial function in ways that can be personalized. Transcriptomic receptivity assays (endometrial receptivity array), single-cell endometrial profiling, microbiome modulation, individualized luteal support (progesterone monitoring and tailoring) have grown evidence that personalizing timing and hormonal support can help some patients,[33,34] however, these still show variable results and need more RCT studies. THE EXPERIMENTAL/EARLY-STAGE APPROACHES The derive eggs from pluripotent stem cells to bypass age-related oocyte decline. The preclinical progress in animals and early human cell work has been addressed with remaining major scientific, safety, and ethical hurdles before clinical use.[35] This is a true long-term prospect (years–decades). Restoring the supporting niche (stromal/endothelial) could improve follicular microenvironment by applying mesenchymal stem cell infusion into ovaries, exosome therapies, and tissue engineering approaches in some early clinical trials/case series, but biological plausibility exists. The robust clinical evidence still limited.[36] AMA is the multifactorial issue. Systematic approaches combined with multimodal interventions including metabolic assessment, mitochondrial adjustment, embryo selection, and endometrial personalization may identify synergistic protocols for AMA IVF treatment in future. Summary The challenges of AMA in IVF primarily revolve around the decline in both oocyte quantity (ovarian reserve) and oocyte quality (increased aneuploidy rates). Successful strategies to enhance IVF outcomes in AMA focus on maximizing egg retrieval and ensuring the transfer of a chromosomally normal embryo into an optimally prepared uterus. Here is a concise summary of strategies to enhance IVF outcomes in AMA, integrating current evidence and future perspectives. Author contributions Writing – Original Draft Preparation, Hsien-Ming Wu; Writing – Review and Editing, Hsien-Ming Wu; Supervision, Chyi-Long Lee. All authors have read and agreed to the final version of the manuscript. Data availability statement Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.