Fertility

How Clinics Choose Which Cycles to Report

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Two clinics can advertise very different success rates while practicing nearly identical medicine. The difference is usually in what got counted: which cycles, which patients, which denominator, which year. None of it requires lying. This is a plain-language tour of the choices that inflate a rate, and how the public federal data lets you undo them and compare clinics on the same terms.

Last updated: July 2026

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What cherry-picking a success rate really means

Cherry-picking a success rate usually is not fraud — it is selection. From several legitimate ways to count outcomes, a clinic presents the one that looks best and leaves the rest unsaid. Because the raw data is collected in a standardized national system, every clinic starts from the same definitions; the room to flatter comes from which figure gets put on the website 1. Knowing the moves lets you ask for the number that actually describes you.

That framing matters, because it changes what you are looking for. You are not trying to catch a lie. You are trying to find out which honest number was chosen and which honest numbers were left out — the denominator, the patient group, the age band, the time window. Each of those is a lever, and each one can lift a percentage without a single word being false.

Choosing the denominator that flatters

The first and most common lever is the denominator — the group of cycles a success is divided by. National reporting defines outcomes several ways: per intended egg retrieval, per new patient, per transfer, and cumulatively 1. A rate quoted "per transfer" is almost always the highest, because it has already removed everyone whose cycle was cancelled or never produced an embryo to move. when a success rate is missing its denominator, the missing denominator is the tactic

So a clinic can report a technically true figure by quietly counting only the cycles that reached the finish line, while a live-birth rate per retrieval — which counts the cycles that failed early — tells a fuller story. Neither is fabricated; they answer different questions. When a rate is missing its denominator, that absence is the move. It is worth asking what a number is divided by before you let its size land.

Choosing which patients get counted

The second lever is the patient mix. A clinic can lift its numbers by treating easier cases — capping the age it accepts, steering poorer-prognosis patients toward donor eggs first, or requiring steps that screen out harder cycles before they count. This case mix and patient selection, not the skill in the lab, is often why clinic success rates mislead when you line two practices up side by side 1.

Refund and multi-cycle money-back programs concentrate this effect, because they are typically offered only to good-prognosis patients, and guidance stresses they should disclose the clinic's own success rates and who is excluded 4. A program that admits mostly favorable cases will naturally post favorable results. The honest way of comparing clinics is within the same age band and diagnosis, so the patient mix is held roughly constant and the medicine is what you are actually comparing.

Lifting the rate by transferring more embryos

A third lever is clinical: transferring two or more embryos at once raises the pregnancy rate for that transfer, which flatters a per-transfer statistic. But guidance recommends elective single-embryo transfer, because moving one embryo achieves comparable cumulative results while sharply cutting the risk of twins and the serious complications multiples carry 3. A rising headline rate built on multiple-embryo transfers is buying the number with added risk to patients and babies. elective single-embryo transfer matches cumulative success with far fewer twins 3

This is why a clinic's single-embryo-transfer rate and its multiple-birth rate are worth reading next to its success rate. A very high pregnancy-per-transfer figure paired with a high twin rate is a signal that the number was pushed rather than earned. The safer, evidence-based approach can show a slightly lower per-transfer figure while producing just as many healthy single babies over a full course of treatment.

Counting a single year and calling it your odds

The fourth lever is time. National ART figures are noncumulative — each one describes a single reporting year, not a patient's full course of treatment 2. A clinic can lean on this either way: quoting a per-cycle snapshot to make a competitor's cumulative figure look inflated, or blurring the line so a one-cycle rate reads like the odds of eventually succeeding. They are different numbers, and the difference is large.

For most patients, IVF is a multi-cycle process, so a cumulative live-birth rate across two or three retrievals is the figure that matches lived experience. When you see a rate, it helps to pin down whether it is one cycle or several, because a clinic choosing the timeframe is choosing the impression. The methodology behind the public data spells out exactly how each measure is defined, which is what lets you tell them apart.

Undoing the cherry-pick with the public data

Every lever above can be reversed with the same standardized data the clinic drew from. Federal law mandates ART success-rate reporting, and both the CDC and SART publish it for anyone to read 5. The national system logged 435,426 cycles on 251,542 patients at 457 clinics in the most recent reporting year, with 94,039 live-birth deliveries 6 — a large, common yardstick you can hold any single clinic against. cumulative live-birth rate — the chance of a baby across several retrievals, not a single cycle

To research a fertility clinic near you, read its report in your own age band, fix the denominator to live birth per retrieval or the cumulative rate, and note its single-embryo-transfer and multiple-birth figures. Comparing clinics only works when you compare the same measure, in the same band, at practices with enough volume that the percentage is not swung by a handful of cycles — clinic volume is part of why one number is steadier than another. That method, plus a short list of first-consult questions, turns a marketing figure back into information. A good success rate is simply one you can map to your own age, diagnosis, and the denominator underneath it.

Common questions

Usually not. Clinics report into a standardized federal system, but how they present their own numbers in advertising is far less regulated. Selecting the most flattering true figure — a per-transfer rate, a best age band, a single good year — is presentation, not fraud. That is exactly why the burden falls on you to read the underlying data rather than the brochure.

A pregnancy or success rate per transfer with no age band and no mention of the denominator. It excludes every cycle that never reached transfer, so it is systematically higher than a live-birth rate per retrieval. If a clinic leads with a large per-transfer figure and does not readily show live birth per retrieval for your age, the gap itself is the story.

Patient mix and reporting choices, mostly. One may accept older or more complex patients; one may report a different denominator; one may transfer more embryos. Smaller clinics also swing more from year to year because a few cycles move the percentage. Comparing the same measure, in the same age band, at clinics of similar volume removes most of the illusion.

Not on its own. An unusually high rate can reflect a clinic that declines difficult cases, transfers multiple embryos, or reports a flattering denominator. Read it alongside the single-embryo-transfer rate, the multiple-birth rate, and the figure for your age band. A number you cannot connect to your own situation, however large, is not evidence about your odds.

The CDC's ART data and the SART reports, both free and public, present outcomes by clinic and by age band using standard definitions. The CDC also has an individualized estimator built from national averages. Starting there, then asking a specific clinic to show you your age band and denominator, is how you compare practices on equal terms.

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A flattering number is a question, not a verdict

  • —A headline success rate with no age band and no stated denominator, that a clinic will not break down for your situation.
  • —A high pregnancy-per-transfer figure alongside a high multiple-birth or twin rate.
  • —A refund or money-back program that will not disclose its own success rates or who it excludes.

This article explains how success-rate figures can be presented selectively; it is general information, not medical advice. It cannot rate any specific clinic. Your own odds depend on your diagnosis and history, which a reproductive endocrinologist can assess.

References

  1. 1.Society for Assisted Reproductive Technology (SART) (2024). National Summary Report (SART CORS Online). Society for Assisted Reproductive Technology. link ✓That ART outcomes are collected in a standardized system and reported several ways (per intended retrieval, per new patient, per transfer, cumulative) broken out by patient age band — the national aggregate, not any single clinic's marketing claim.
  2. 2.Centers for Disease Control and Prevention (2024). NASS Technical Notes. CDC National ART Surveillance System. linkThat national ART figures are noncumulative and describe a single reporting year, and that each success measure is defined methodologically — the basis for telling a per-cycle snapshot from a cumulative rate.
  3. 3.Practice Committees of ASRM and SART (2021). Guidance on the limits to the number of embryos to transfer: a committee opinion. American Society for Reproductive Medicine (Fertility and Sterility). linkThat elective single-embryo transfer achieves comparable cumulative results with far lower multiple-birth risk, so transferring more embryos to raise a per-transfer rate trades safety for a headline number.
  4. 4.Ethics Committee of ASRM (2023). Financial "risk-sharing" or refund programs in assisted reproduction: an Ethics Committee opinion. American Society for Reproductive Medicine (Fertility and Sterility). linkThat refund/risk-sharing programs should disclose the clinic's own success rates and exclusions, and that they are typically offered to good-prognosis patients — a source of favorable patient selection.
  5. 5.Centers for Disease Control and Prevention (2024). ART Success Rates. CDC Division of Reproductive Health. linkThat federal law mandates ART success-rate reporting and the CDC (with SART) publishes it, giving patients a standardized source to check a clinic's claims against.
  6. 6.Centers for Disease Control and Prevention (2024). National ART Summary (2022 data dashboard). CDC Division of Reproductive Health. linkNational ART scale for the most recent reporting year (2022): 435,426 cycles on 251,542 patients at 457 clinics, yielding 94,039 live-birth deliveries.

6 sources, numbered by first appearance. General health information, not medical advice. AI-assisted editorial content — citations link their sources. Editorial policy

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