The Challenge of Uncertainty in Fertility Treatment

For anyone considering IVF, the most challenging question is often: “What are my chances?” The treatment journey can feel like a marathon of uncertainty, and research confirms that this psychological burden is a primary reason why some patients discontinue treatment, even when their medical prognosis remains favourable.

As your fertility specialist, my role is to partner with you in navigating this uncertainty. While no one has a crystal ball, we can use a combination of personalised clinical data and evidence-based tools to create the most realistic picture possible of your individual situation.

This article explains how we build your personal fertility prognosis, what prediction tools can and cannot do, and how to use available resources wisely during your treatment journey.

A simple visual workflow from scheduling to continuous improvement. Clean line icons illustrate each step of the process.

Part 1: The Foundations – What Actually Predicts Your Outcome

Online calculators can provide generic estimates, but a clinical prognosis is built on your specific biology. When you consult with a fertility specialist, we integrate several key data points that are far more personalized than any web-based tool can provide.

The Pillars of Your Fertility Assessment

Your Age: This is the most significant factor influencing egg quality and chromosomal health. The risk of chromosomal abnormalities in embryos is lowest between ages 26-30 and increases predictably with maternal age. However, age is just one piece of the puzzle.

Your Ovarian Reserve: These are the two most important clinical biomarkers we use to predict your likely response to stimulation:

• Anti-Müllerian Hormone (AMH): A blood test that provides a strong indication of your remaining egg quantity. This single measurement is one of the most powerful predictors of how many eggs you’re likely to retrieve in a stimulation cycle.
• Antral Follicle Count (AFC): A baseline ultrasound to count the “resting” follicles visible in your ovaries. This complements AMH data and helps us personalise your stimulation protocol.

Your Specific Fertility Diagnosis: Your prognosis is directly influenced by your specific medical history:

• Ovulatory Disorders (e.g., PCOS): Often associated with retrieving a higher number of eggs, though other factors may affect egg quality or implantation.
• Endometriosis: May impact egg quantity, egg quality, or implantation success depending on severity and location.
• Tubal Factor Infertility: Typically does not affect egg quality or quantity, making IVF particularly effective for this diagnosis.
• Male Factor Infertility: May primarily affect fertilisation rates, often addressed successfully with ICSI (intracytoplasmic sperm injection).
• Unexplained Infertility: While frustrating diagnostically, these patients often have favourable IVF outcomes as there are no identified barriers to conception.

Your Previous Cycle History: Having had a successful spontaneous successful conception leading to childbirth is arguably the most powerful factor in predicting your chances of successful IVF treatment. Additionally, If you’ve undergone IVF before, how your body responded to treatment is one of the most powerful predictors of future outcomes. Your previous retrieval numbers, fertilisation rates, and embryo development patterns provide invaluable data.

A specialist’s prediction is not a single number but a dynamic assessment that synthesises all these factors—an assessment that no public calculator can replicate because it lacks access to your AMH, AFC, and detailed medical history.

Part 2: The Tools – How to Use IVF Prediction Calculators Wisely

You’ve likely encountered IVF “success estimators” online. These tools are built using data from thousands of past IVF cycles and can provide useful context, but understanding their limitations is essential.

Available Prediction Tools

SART Calculator (United States): The Society for Assisted Reproductive Technology maintains a prediction tool based on US national IVF registry data. It provides age-stratified success rates based on hundreds of thousands of cycles.

CDC IVF Success Estimator (United States): The Centres for Disease Control provides a similar tool based on mandatory reporting from US fertility clinics.

OPIS Calculator (International): Developed by researchers at the University of Aberdeen, this tool predicts cumulative live birth chances over multiple IVF cycles based on UK and European data.

HFEA Data (United Kingdom): The Human Fertilisation and Embryology Authority publishes detailed outcome data from UK clinics, allowing for clinic-specific and national-level comparisons.

What These Tools Do Well

• Broad context: They provide age-stratified success rates that can help you understand general patterns in IVF outcomes for people in your demographic group.
• Realistic baseline expectations: They can counter both excessive optimism and unwarranted pessimism by grounding expectations in real-world data.
• Starting point for conversation: They generate useful questions to discuss with your specialist about how your specific situation might differ from population averages.

Critical Limitations to Understand

They Cannot Personalise Beyond Basic Demographics: Most calculators use only age and sometimes diagnosis category. They cannot incorporate:

• Your specific AMH level (which can vary 10-fold among same-age women)
• Your AFC (which directly predicts ovarian response)
• Your partner’s sperm quality parameters
• Your BMI, which significantly affects outcomes
• Your previous treatment responses
• Clinic-specific success rates and protocols

They Provide Static Predictions: Once you begin treatment, these calculators cannot update based on your actual response. If you retrieve 8 eggs instead of the predicted 15, the calculator cannot incorporate this information to refine downstream predictions about fertilization, embryo development, or ultimate success probability.

They Focus on Binary Outcomes: Most calculators predict “live birth: yes or no” rather than providing information about intermediate stages. They won’t tell you how many eggs to expect, how many might fertilise, or how many embryos you might have for genetic testing or future transfers.

They Don’t Show Uncertainty Ranges: A prediction of “40% chance of live birth” doesn’t convey whether your actual probability might be 35-45% or 20-60%. Understanding the width of uncertainty matters for decision-making.

How to Use These Tools Effectively

1. Use them early in your journey to establish broad expectations and understand how outcomes vary by age and diagnosis.
2. Bring questions to your specialist that arise from reviewing these tools, particularly if the predictions seem surprisingly high or low based on your understanding of your situation.
3. Recognise them as population-level data that will be refined substantially through your individual clinical assessment.
4. Never use them as a substitute for personalised counselling with your specialist, who can integrate your specific biomarkers and medical history.

The most valuable “prediction” isn’t a number from a calculator—it’s the ongoing conversation you have with your clinical team as your real-time results emerge during treatment.

Part 3: Understanding Genetic Testing in IVF

The genetic testing landscape can be confusing. It’s essential to understand the profound difference between established, standard-of-care testing and experimental technologies that remain under investigation.

Standard-of-Care: Preimplantation Genetic Testing for Aneuploidy (PGT-A)

What It Is: PGT-A is an established, widely used test that screens embryos for the correct number of chromosomes (a state called “euploidy”). Each human cell should contain 23 pairs of chromosomes. Embryos with incorrect chromosome numbers (aneuploid embryos) typically fail to implant, result in miscarriage, or in rare cases lead to chromosomal conditions.

Why We Use It: The leading cause of IVF failure and miscarriage is aneuploidy. The risk increases significantly with maternal age—while approximately 25% of embryos are aneuploid for women in their early 30s, this rises to over 75% by age 42.

How It Helps: By identifying and transferring a euploid embryo, PGT-A:

• Increases the chance of successful pregnancy from a single embryo transfer
• Reduces the risk of miscarriage
• Shortens the time to pregnancy by avoiding transfers of embryos unlikely to succeed
• Reduces the cumulative number of embryo transfers needed

The Evidence Base: PGT-A is supported by decades of research, including randomised controlled trials demonstrating its clinical utility. It is considered standard of care in modern fertility practice, particularly for patients of advanced maternal age, those with recurrent miscarriage, or those with multiple failed transfers.

Experimental Technology: Polygenic Embryo Screening (PES)

What It Is: You may encounter articles or advertisements for Polygenic Embryo Screening (also called PGS or polygenic risk score testing). This experimental technique claims to screen embryos for their future risk of developing complex diseases like diabetes, heart disease, schizophrenia, or certain cancers.

Unlike PGT-A, which identifies present chromosomal abnormalities with high accuracy, PES attempts to predict future disease risk based on the cumulative effect of many genetic variants, each contributing a tiny amount to overall risk.

The Clinical & Ethical Consensus: This is where we must be extremely clear and cautious. This technology is not considered ready for clinical use outside of research contexts.

Professional Guidelines:

• The Human Genetics Society of Australasia (HGSA), the peak body for clinical genetics in Australia, has stated that “further evaluation is required before polygenic scores can be routinely implemented” and urges clinicians to “proceed with caution.”
• A 2022 review by Australian experts in the journal Human Reproduction concluded that PES is “not ready for prime time.”
• A comprehensive 2024 international review in Human Reproduction Update by Capalbo and colleagues analysed this technology in depth. Their conclusion: due to “practical limitations and possible harms,” PES “should be offered only within a research context.”

Why the Caution?: The concerns about polygenic embryo screening include:

• Limited predictive accuracy: For most complex diseases, polygenic scores explain only a small fraction of disease risk. Environmental factors, rare genetic variants not captured by these scores, and random chance play substantial roles.
• Ancestry gaps: These scores perform substantially worse for individuals of non-European ancestry because most genetic databases used to develop them are composed primarily of European populations.
• Uncertain clinical utility: Even when scores correctly rank embryos by genetic risk, the absolute differences in disease probability may be small and may not translate into meaningful differences in health outcomes.
• Psychological burden: Providing probabilistic risk information for multiple diseases across multiple embryos creates complex, emotionally fraught decision-making that may not improve outcomes and may increase patient distress.
• Ethical concerns: The technology raises concerns about the potential expansion from disease screening to enhancement selection, societal pressures, and equitable access.

Current Appropriate Use: If you’re interested in contributing to the development of this technology, some research studies are investigating PES with appropriate informed consent, ethical oversight, and long-term outcome tracking. This is the appropriate context for exploring its potential while gathering the evidence needed to determine whether it should eventually enter clinical practice.

As Your Specialist, My Commitment

My commitment is to evidence-based medicine. Therefore, PES is not a service we offer, as it does not meet the standard of care and its use is not supported by the peak ethical and clinical bodies in our field.

When robust, peer-reviewed evidence demonstrates clinical benefit and professional guidelines support its use, we will integrate new technologies into practice. Until then, we focus on established, validated approaches that we know help our patients achieve their family-building goals.

Part 4: The Real-Time Advantage of Specialist Care

The most sophisticated “prediction tool” you have is not an algorithm—it’s the dynamic assessment your clinical team provides as your treatment progresses.

How Real-Time Clinical Assessment Works

Before Stimulation Begins: Based on your age, AMH, AFC, and diagnosis, we estimate your likely response to medication and set appropriate expectations for egg retrieval numbers.

During Stimulation Monitoring: Through serial ultrasounds and bloodwork, we track your actual follicle development and hormone levels, refining our predictions in real-time and adjusting medication protocols as needed.

After Egg Retrieval: Your actual egg number immediately updates our expectations for all downstream outcomes. We can provide refined probabilities for:

• How many eggs are likely mature
• Expected fertilisation numbers
• Potential embryo development
• Likelihood of having embryos for genetic testing
• Probability of success from this cycle
• Whether additional cycles might be beneficial

After Fertilisation and Embryo Development: Each stage provides new information that narrows uncertainty and helps guide decisions about:

• Fresh versus frozen transfer
• Single versus multiple embryo transfer
• Whether to pursue genetic testing
• Optimal timing for your next cycle if needed

After Genetic Testing Results: If you’ve opted for PGT-A, knowing your specific number of euploid embryos provides the most accurate prediction possible for your ultimate success probability and family-building options.

The Irreplaceable Value of Experience

Calculators process numbers according to fixed algorithms. Experienced specialists integrate:

• Pattern recognition: Having guided thousands of patients through treatment, we recognise subtle indicators that algorithms miss.
• Protocol optimisation: We adjust stimulation protocols in real-time based on your response, something no predictive model can do.
• Contextual judgment: We consider factors like embryo morphology quality, endometrial receptivity, and your overall health status—variables that calculators cannot capture.
• Emotional support and realistic counselling: We help you interpret probabilities in the context of your specific goals, timeline, and emotional resources.

Part 5: Managing Expectations While Maintaining Hope

One of the most important aspects of IVF treatment is maintaining the psychological balance between realistic expectations and sustained hope.

What Research Tells Us

Studies show that patients often overestimate their chances of immediate success from a single IVF cycle while underestimating their cumulative chances across multiple cycles. This pattern can lead to:

• Excessive disappointment after an unsuccessful first cycle
• Premature treatment discontinuation
• Difficulty making informed decisions about how many cycles to pursue

A Framework for Realistic Optimism

Understand Single-Cycle vs. Cumulative Probabilities: Your chance of success from one cycle may be modest, but your cumulative probability across two or three cycles is typically much higher. Many patients require multiple attempts to achieve success.

Focus on What You Can Control: While you cannot control egg quality or embryo development outcomes, you can:

• Optimise your health through appropriate diet, exercise, and stress management
• Adhere carefully to medication protocols
• Choose a clinic and specialist whose approach aligns with your values and needs
• Maintain open communication with your care team

Prepare for Multiple Scenarios: Before each treatment stage, discuss with your specialist:

• Best-case outcomes and what they would mean for your next steps
• Expected outcomes and the typical path forward
• Challenging outcomes and how you would respond

This scenario planning reduces the psychological shock of unexpected results and helps you make decisions more rationally rather than emotionally.

Recognise the Role of Chance: Even with perfect protocols and optimal patient characteristics, biological processes involve inherent randomness. An unsuccessful cycle doesn’t necessarily mean something is wrong—it may simply reflect natural variation in complex biological processes.

Part 6: Questions to Ask Your Specialist

To get the most from your consultations, consider asking:

1. About Your Specific Situation:
   • Based on my AMH, AFC, age, and diagnosis, what is your prediction for my response to stimulation?
   • What factors in my history make you more or less optimistic than average for someone my age?
   • What would you consider a good, expected, and disappointing outcome for my first retrieval?
2. About Treatment Protocols:
   • What stimulation protocol do you recommend for my specific situation and why?
   • How will we monitor my response and what adjustments might we make?
   • What are the most common complications for someone with my profile?
3. About Decision Points:
   • Under what circumstances would you recommend PGT-A testing for my embryos?
   • If my first cycle is unsuccessful, what information will we gain to inform our approach to a second cycle?
   • At what point would you recommend considering alternative approaches like donor eggs or embryos?
4. About Cumulative Planning:
   • What is your estimate of my chances across multiple cycles, not just one?
   • How many cycles do you typically recommend for someone with my profile before reassessing the approach?
   • What financial and emotional planning should I consider for a realistic treatment timeline?

Your Partner in Planning Your Family

Understanding your fertility options should not feel like deciphering marketing materials or navigating commercial pressures. It should feel like a partnership grounded in evidence, transparency, and shared decision-making.

While prediction models and calculators represent interesting developments in fertility medicine, they are not substitutes for:

• A thorough clinical assessment incorporating your specific biomarkers
• Real-time monitoring and protocol adjustment during treatment
• Experienced clinical judgment about your individual case
• A trusted relationship with your specialist

My role is to interpret your unique results at every stage, helping you make the best, most informed decisions for your family—balancing optimism with realism, hope with evidence, and innovation with established standards of care.

When new technologies mature from experimental investigation to proven clinical benefit, with endorsement from professional medical bodies and robust peer-reviewed evidence, we will integrate them into practice. Until then, we focus on what we know works: personalised care, evidence-based protocols, and partnership with you throughout your journey.