What Your RE Isn’t Telling You About IVF Success Rates

You’ve probably done this: visited a fertility clinic’s website, found their “success rates” page, and tried to compare their numbers to another clinic across town. Maybe one advertised 65% and another 52%, and you assumed the first one was better.

That assumption is almost certainly wrong. And the fact that the fertility industry lets you make it—that SART and CDC data are presented in ways that invite exactly this kind of misleading comparison—is one of the most underreported problems in reproductive medicine.

This is not a conspiracy. Most fertility clinics are run by competent, ethical physicians. But the incentive structure around success rate reporting creates systematic distortions that every patient should understand before choosing a clinic based on numbers alone.

How IVF Success Rates Are Reported

In the United States, fertility clinics report outcome data to two organizations: the Society for Assisted Reproductive Technology (SART) and the Centers for Disease Control and Prevention (CDC). SART membership is voluntary (though most large clinics participate), and CDC reporting is mandated by the 1992 Fertility Clinic Success Rate and Certification Act.

The data is published approximately 16 months after the end of the reporting year—so the most recent available figures always lag clinical reality. This delay is necessary because live birth outcomes aren’t known until months after treatment, but it means you’re making decisions about 2026 care based on 2024 (or sometimes 2023) data.

SART’s own website includes a disclaimer that would alarm any patient who actually read it: the data “should not be used for comparing clinics” because “clinics may have differences in patient selection and treatment approaches which may artificially inflate or lower pregnancy rates.”

That disclaimer is accurate. Here’s why.

Five Ways Success Rates Mislead

1. Patient Selection Bias

The most powerful tool a clinic has for inflating its success rates is choosing who it treats. A clinic that accepts only younger patients with good prognoses will have higher success rates than one that takes on complex cases—not because it’s a better clinic, but because it started with easier patients.

This isn’t hypothetical. Some clinics discourage or decline treatment for patients with diminished ovarian reserve, advanced age, or prior failed cycles—precisely the patients who need expert care the most. A clinic with a 55% success rate that turns away difficult cases is not necessarily better than a clinic with a 42% success rate that treats everyone who walks in the door. The second clinic may actually be more skilled, because it achieves reasonable outcomes with harder cases.

2. Which Number Are You Looking At?

There are multiple ways to define “success,” and they produce very different numbers:

Clinical pregnancy rate counts any pregnancy confirmed by ultrasound—including those that end in miscarriage. This is the most flattering number, and the one most commonly used in clinic marketing.

Live birth rate per transfer counts only pregnancies that result in a living baby. This is the most meaningful number for patients, and it’s always lower than the clinical pregnancy rate.

Live birth rate per cycle started includes cycles that were canceled before retrieval or that produced no viable embryos for transfer. This is the most conservative (and most honest) denominator.

Cumulative live birth rate per retrieval tracks all transfers (fresh and frozen) resulting from a single egg retrieval over a two-year period. This is the best measure of what a retrieval cycle is actually worth—but it’s the hardest to find.

When a clinic advertises “60% success rate,” ask: 60% of what? Clinical pregnancies per transfer? Live births per cycle started? The difference between these numbers can be 15–20 percentage points.

3. Age Stratification Matters Enormously

A clinic’s “overall” success rate is heavily influenced by the age distribution of its patient population. A clinic that treats a younger patient pool will have higher aggregate numbers, independent of clinical quality.

SART reports data in age brackets (under 35, 35–37, 38–40, 41–42, over 42). When comparing clinics, look at the age bracket that matches yours—not the overall number. The overall number is nearly meaningless for your individual decision. For a full breakdown by age, see our guide to IVF success rates by age.

4. Fresh vs. Frozen vs. Donor

Success rates for fresh transfers, frozen embryo transfers, own-egg cycles, and donor egg cycles are all different—sometimes dramatically. Donor egg IVF has success rates of 50–65% regardless of the recipient’s age, because the donor’s eggs are young. A clinic that does a lot of donor egg work will have higher aggregate numbers.

When comparing clinics, make sure you’re looking at the same type of cycle. Comparing your own-egg fresh transfer prospects at Clinic A against Clinic B’s aggregate number (which includes donor cycles) is comparing apples to oranges.

5. The Self-Reporting Problem

SART data is self-reported by clinics and is not independently verified. While most clinics report accurately, the system relies on good faith. There is no equivalent of a financial audit. Some progress toward independent verification is being made, but as of 2026, the data remains essentially honor-system.

Additionally, SART currently lacks data on egg freezing and warming outcomes, which means patients pursuing fertility preservation have no standardized way to compare clinics on the metric that matters most to them.

How to Actually Evaluate a Clinic

If success rate numbers can’t be taken at face value, what should you use instead? A multi-factor approach:

Ask for age-matched, own-egg live birth rates per cycle started. This is the single most honest number a clinic can give you. If they can’t or won’t provide it for your specific age bracket and diagnosis, that tells you something.

Ask about their patient population. Do they treat a wide range of patients, including difficult cases? Or do they primarily treat younger patients and donor cycles? A clinic that takes on complex cases and still posts solid numbers is demonstrating real clinical skill.

Evaluate the lab independently. The embryology lab is where IVF outcomes are made. Ask about the lab director’s credentials, blastocyst conversion rates (the percentage of fertilized eggs that develop to day-5 blastocysts), and whether the lab is accredited by CAP or a similar body.

Look at singleton rates. A clinic that achieves good success rates while maintaining low multiple pregnancy rates (by transferring single embryos) is demonstrating sophisticated clinical practice. High success rates achieved through multi-embryo transfers are inflated at the cost of patient safety.

Check SART for a baseline, not a verdict. Use the SART Clinic Summary Report to establish a baseline, then dig deeper during your consultation. Compare clinics within the same age bracket, looking at the same cycle type (own egg vs. donor, fresh vs. frozen).

Ask the hard question. “What percentage of patients who come to you for treatment do you decline to treat?” A clinic that declines very few patients and still posts strong numbers is likely genuinely excellent. A clinic that declines many patients is likely curating its statistics.

The Consolidation Problem

There is a growing structural issue in the U.S. fertility industry that makes success rate comparisons even more complex: clinic consolidation. Over the past decade, large fertility networks—including US Fertility, IVI RMA, CCRM, Shady Grove (now part of US Fertility), and others—have acquired hundreds of independent practices. This matters for patients evaluating success rates because network-level data can mask wide variation between individual clinic locations.

A network may advertise a national average success rate that reflects its best-performing labs, while a specific location within that network may have significantly different outcomes based on its embryology team, local patient demographics, and lab equipment. When you see a network name on a SART report, dig into the specific location where you would be treated, not the corporate umbrella.

Consolidation also creates economic incentives that can influence treatment recommendations. Privately equity-backed networks face growth and profitability targets that may not always align with the most conservative clinical approach. This is not unique to fertility medicine—it is a broader trend in healthcare—but it adds another reason to ask probing questions about why a particular treatment plan is being recommended for you.

What Your RE Should Tell You (But Might Not)

A responsible reproductive endocrinologist should proactively tell you your personalized probability of success based on your age, diagnosis, ovarian reserve, and partner’s sperm parameters—not the clinic’s aggregate rate. If your RE quotes the clinic’s overall success rate in response to “what are my chances?” without qualifying it, that’s a gap in communication.

Ask for a personalized estimate. The best clinics use prediction models (based on age, AMH, AFC, diagnosis, BMI, and prior cycle history) to give you a realistic per-cycle and cumulative probability of live birth. That number may be lower than what you see on the website, but it will be far more useful for planning—both emotionally and financially.

A second opinion from an independent RE—one not affiliated with the clinic you’re evaluating—can also be invaluable. A 30-minute consultation that costs $200–$500 may save you thousands in unnecessary treatment or steer you toward a clinic better suited to your diagnosis. If your current clinic discourages second opinions, that itself is a data point worth noting.

For patients considering clinics abroad as an alternative to high domestic pricing, the same evaluation principles apply—with the additional step of verifying international accreditation standards. Our IVF abroad guide covers how to vet international clinics using the same rigor you would apply domestically.

The Bottom Line

IVF success rates are a useful starting point for evaluating clinics, but they are not a reliable endpoint. The numbers are shaped by who a clinic chooses to treat, how they define “success,” which cycle types they include, and whether they prioritize singleton pregnancies. Smart patients look past the headline number and ask the questions that reveal what’s behind it.

For more on navigating the IVF decision, see our guides to when to escalate from IUI to IVF, the IVF timeline, and whether add-ons like PGT-A testing are worth the additional cost.