Fertility

How the HFEA Traffic-Light System Rates Add-Ons

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Fertility clinics offer a long menu of add-ons — genetic testing, assisted hatching, time-lapse imaging, and more — often for thousands of dollars each. The HFEA scores every one of them against the actual evidence and publishes the result as a color-coded rating anyone can read. Here is what the ratings mean, why so many land in the cautious tiers, and how to use them even outside the UK.

Last updated: July 2026

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What the HFEA traffic-light system is

The HFEA — the Human Fertilisation and Embryology Authority, the UK's fertility regulator — rates optional IVF add-ons on a five-tier, color-coded scale so patients can see how much evidence stands behind each one. On that scale most add-ons are rated as lacking good evidence of benefit, and some are flagged as potentially causing harm 1. The system exists because these extras are sold widely, at real cost, with claims that outrun the trials. an add-on's rating tells you what the evidence shows, not whether you should have it

An add-on is any procedure offered on top of a standard IVF cycle — an extra test, an extra step in the lab, an extra medication. The traffic-light ratings do not tell you whether to have one; they tell you what the published evidence currently shows, in a form you can read in seconds. That alone reframes the conversation from "do you want the best chance?" to "what does the evidence say this actually adds?"

How the ratings work, top to bottom

The scale runs like a traffic light, from a top rating for add-ons supported by more than one good-quality trial showing they are effective and safe, through middle ratings for those with conflicting or no reliable evidence, down to a warning rating for add-ons that may reduce your chance of a birth or cause harm 1. Color makes the level obvious at a glance, and each rating links to the evidence behind it.

The point of the design is that you do not need to read the studies yourself to see where an add-on stands. A green-type rating is the only one that means the evidence currently supports the extra; every rating below it is a signal to ask harder questions. Crucially, a low rating is not an accusation that a treatment is a scam — it means the proof of benefit is not there yet, which is a different and more useful statement.

Why most add-ons sit in the cautious tiers

Most add-ons land below the top rating because the trials either have not been done, are too small, or came back showing no benefit. The clearest example is preimplantation genetic testing for aneuploidy, or PGT-A: a large multicenter randomized trial in good-prognosis patients found it did not improve ongoing-pregnancy rates compared with standard embryo selection 2. A procedure can be sophisticated, expensive, and widely offered and still not move the outcome that matters. PGT-A — preimplantation genetic testing for aneuploidy, which screens embryos for the right number of chromosomes

That gap — between how advanced an add-on sounds and what it delivers — is exactly what the ratings are built to expose. Add-ons on the HFEA list include PGT-A, assisted hatching, the endometrial scratch, and time-lapse embryo imaging 1, and most are rated as unproven. When a clinic presents one of these as routine, the traffic-light rating is the counterweight: it lets you ask why a step the evidence does not yet support is being treated as standard.

ICSI: an add-on with an indication, not a default

ICSI — injecting a single sperm directly into each egg — is a good illustration of an add-on that is right for some people and oversold to others. Guidance is clear that, absent a male-factor problem or a prior fertilization failure, using ICSI on all eggs does not improve live-birth rates over standard insemination in the dish 3. It is a targeted tool, not a general upgrade, even though some clinics apply it to nearly everyone.

The traffic-light logic applies here too: ICSI has strong evidence for a specific indication and weak evidence as a blanket policy. If a clinic recommends it, the useful question is which of your results — a semen analysis, a past cycle — makes it necessary for you. An add-on justified by your diagnosis is medicine; the same add-on applied by default is a line item.

The standard cycle is often the better value

Because most add-ons are unproven, the plain IVF cycle they are added to already represents the best-evidenced path for many patients. A standard elective single-embryo transfer, for instance, achieves pregnancy rates comparable to transferring more embryos while sharply lowering the risk of twins and the complications that come with them 4. Spending thousands on extras to boost a cycle can buy less than the marketing implies. elective single-embryo transfer matches multi-embryo pregnancy rates with far lower twin risk 4

This is where the ratings turn into money. Vetting extras against the HFEA add-on ratings before you agree to them is a concrete way to keep a cycle's cost tied to its evidence. A reasonable set of questions to ask about IVF add-ons is simply: what is this rated, what would it add for me specifically, and what does it cost — asked for each extra on the quote.

What a rating can and can't tell you

A traffic-light rating describes the state of the evidence, not your personal odds, and it changes as new trials are published. A top rating means an add-on is currently well supported for the population studied, not that it will help you; a low rating means proof of benefit is missing today, not that it can never work. Ratings are a starting point for a conversation, not a verdict on your case.

Used well, the system is a filter against fertility add-ons the evidence doesn't support. If a clinic pushes an extra that the ratings flag as unproven and cannot explain why your situation is the exception, that pattern is itself one of the fertility clinic red flags worth noticing. It is fair to ask whether assisted hatching, or any add-on, actually improves IVF success for someone with your history — and to let the evidence, not the brochure, answer.

Common questions

The colors run like a traffic light: a green-type rating means more than one good-quality trial shows the add-on is effective and safe; the middle tiers mean the evidence is conflicting or absent; and a red-type rating warns the add-on may lower your chance of a birth or cause harm. Only the top rating means the evidence currently supports paying for it.

Demand, habit, and revenue all play a role. Patients under pressure often want to feel they are doing everything possible, and add-ons answer that wish even when the trials do not support them. Some add-ons also have promising early data that has not yet held up in large trials. Offering one is not automatically wrong — presenting it as standard when it is unproven is the problem.

The regulator is British, but biology and the underlying studies are not. An add-on's evidence is the same on both sides of the Atlantic, so the HFEA ratings work as a free, independent checklist for any patient. US bodies like ASRM reach similar conclusions on several add-ons. You can bring the ratings to a US consult and ask your clinic to respond to them.

Not by itself. A low rating means the proof of benefit is thin, which is a reason to ask why it is being recommended for you specifically — not an automatic no. For some people, an add-on with weak general evidence still has a sound individual rationale. The rating gives you the standing to have that conversation instead of paying on faith.

They are updated as new evidence appears, so an add-on's rating can move up or down over time. That is a feature, not a flaw: it means the scale reflects the current state of the trials rather than a fixed opinion. Checking the live ratings before a cycle, rather than relying on what you heard a year ago, is the way to use them.

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Add-ons are usually a value question, not a safety one

  • —A clinic that presents an unproven add-on as standard or mandatory and cannot say what it would add for your specific diagnosis.
  • —An add-on rated as potentially harmful being recommended without a clear, individual reason.
  • —Pressure to pay for several extras at once, framed as your best chance, with no discussion of the evidence.

This article explains how the HFEA rates IVF add-ons; it is general information, not a treatment recommendation. Whether any add-on makes sense for you depends on your diagnosis and history, which only your fertility specialist can weigh.

References

  1. 1.Human Fertilisation and Embryology Authority (2024). Treatment add-ons with limited evidence. Human Fertilisation and Embryology Authority (UK). link ✓That the HFEA rates IVF add-ons on a five-tier, color-coded scale by strength of evidence, that most add-ons lack good evidence of benefit and some may cause harm, and that the rated add-ons include PGT-A, assisted hatching, endometrial scratch, and time-lapse imaging.
  2. 2.Munné S, et al. (STAR Study Group) (2019). Preimplantation genetic testing for aneuploidy versus morphology as selection criteria for single frozen-thawed embryo transfer in good-prognosis patients: a multicenter randomized clinical trial. Fertility and Sterility. doi:10.1016/j.fertnstert.2019.07.1346That in a large multicenter randomized trial of good-prognosis patients, PGT-A did not improve ongoing-pregnancy rates versus morphology-based embryo selection.
  3. 3.Practice Committees of ASRM and SART (2026). Intracytoplasmic sperm injection for nonmale factor indications: a committee opinion. American Society for Reproductive Medicine (Fertility and Sterility). linkThat routine ICSI on all eggs does not improve live-birth rates absent a male factor or prior fertilization failure, and is a targeted add-on rather than a default upgrade.
  4. 4.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 pregnancy rates comparable to transferring more embryos while sharply lowering multiple-birth risk — evidence the standard cycle performs well without add-ons.

4 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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