IVF Add-ons Explained: What the HFEA Ratings Mean

If you are planning IVF, you will probably be offered at least one "add-on": an extra test or technique on top of standard treatment, usually at an extra cost. After a long wait for a baby, it is natural to want every possible advantage. The UK fertility regulator, the HFEA, rates the most common add-ons on the strength of the evidence behind them. This guide explains what the ratings mean, what they say about the add-ons our partner clinics commonly offer, and what to ask before you pay for one.

Short answer: IVF add-ons are optional extras on top of standard treatment. The HFEA gives each one a traffic-light colour, from green (high-quality evidence that it works) to red (it may reduce the effectiveness of treatment, or there are safety concerns). At the time of writing, none of the six add-ons covered here (EmbryoGlue, endometrial scratch, ERA, time-lapse imaging, assisted hatching and PGT-A) is rated green for improving the chance of having a baby; PGT-A is rated green only for reducing miscarriage. Before you pay, ask why the add-on is recommended for you, what the evidence shows and what it costs, in writing.

What is an IVF add-on?

The HFEA describes add-ons as optional, non-essential treatments or tests offered in addition to proven fertility treatment such as IVF. They usually come with the claim that they improve your chances, but for most patients the evidence is missing or not very reliable. The HFEA points out that, for most people, routine cycles of proven treatment work without any add-ons, and that if you are paying yourself, the money may go further on another cycle of standard IVF. Some add-ons may still help particular groups, or help with other outcomes, such as lowering the risk of miscarriage or of ovarian hyperstimulation syndrome (OHSS).

How does the HFEA rating system work?

The HFEA introduced add-on ratings in 2019 and launched an updated five-colour system in October 2023. Each add-on is assessed by its Scientific and Clinical Advances Advisory Committee, which reviews the published studies:

• Green: on balance, high-quality evidence shows the add-on improves the outcome.
• Amber (shown as a yellow light on the HFEA website): it is not clear whether it works, because good-quality studies disagree.
• Grey: there is not enough good-quality evidence to give a rating.
• Black: on balance, good-quality evidence shows it has no effect on the outcome.
• Red: there are potential safety concerns, or the evidence shows it may reduce the effectiveness of treatment.

The main rating is about the chance of having a baby for most patients. Some add-ons also have ratings for other outcomes, such as miscarriage, or for groups such as older patients. The HFEA and eight patient and professional bodies have also agreed that add-ons without strong evidence of safety or effectiveness should only be offered in a research setting, and that patients should not be charged extra to take part in research.

What do the ratings say about common add-ons?

These are the add-ons our partner clinics commonly offer, with their current HFEA rating for the chance of having a baby:

Source: HFEA treatment add-on ratings (page last reviewed 28 September 2026). Ratings can change, so check the HFEA website before you decide.

EmbryoGlue

EmbryoGlue is one brand of transfer fluid containing hyaluronan, which may help the embryo implant. The HFEA rates it amber: two high-quality studies suggest it may help, but more are needed. The NICE guideline NG257 (2026) makes no specific recommendation on it. The European Society of Human Reproduction and Embryology (ESHRE) is more positive: its 2023 recommendations support it, but the benefit was seen after fresh transfers, not frozen ones, and ESHRE advises combining it with single embryo transfer and monitoring multiple pregnancy rates.

Endometrial scratch

A thin plastic tube lightly scratches the womb lining before IVF, on the theory that healing makes the lining more receptive. The HFEA rates it amber for IVF or ICSI patients and grey for recurrent implantation failure. NICE NG257 says it should not be offered to improve IVF outcomes, and ESHRE does not recommend it for routine use. The HFEA notes it can be painful and cause some bleeding, with a small risk of infection.

ERA and other receptivity tests

An endometrial receptivity test, such as the Endometrial Receptivity Array (ERA), analyses a biopsy of the womb lining to predict when an embryo is most likely to implant, and the transfer in a later cycle is timed to match. The HFEA rates it red and questions whether the test is accurate and whether this "window" stays the same from cycle to cycle. NICE NG257 says not to offer receptivity testing, including microbiome tests of the lining: the evidence showed no difference in pregnancy or live birth rates, and a higher rate of pregnancy loss. The HFEA adds that it requires a freeze-all cycle.

Time-lapse imaging

A camera inside the incubator takes thousands of images, so embryos can be assessed without being taken out. The HFEA rates it black, whether embryos are assessed by software or by an embryologist. NICE NG257 found no benefit for selecting embryos, but made no recommendation against it, because the stable, undisturbed incubation may have other benefits. ESHRE does not recommend it as a way to improve live birth rates.

Assisted hatching

A laser, acid or another tool is used to thin or open the embryo's outer shell, the zona pellucida, to help it "hatch" before implanting. The HFEA rates it grey and notes there is always some risk of damaging embryos with this kind of procedure. NICE has advised against offering it since 2004, because it has not been shown to improve pregnancy rates, and that advice remains in NG257. See our assisted hatching page for more.

PGT-A

Pre-implantation genetic testing for aneuploidy (PGT-A) checks a few cells from each embryo, usually on day 5 or 6, for the number of chromosomes. The HFEA rates it red for the chance of having a baby, green for reducing miscarriage, and grey for both outcomes in older women. As a selection tool, it often leaves fewer embryos to transfer and can mean a longer wait for a pregnancy. NICE NG257 says not to offer PGT-A to improve live birth rates. Testing for a specific inherited condition is different; our guide to genetic testing explains the options.

Are there other extras to ask about?

ICSI, where a single sperm is injected into each egg, is widely used, including where there is no male fertility problem. NICE NG257 says not to use ICSI for non-male factor problems when the semen results are normal, and advises against IMSI and PICSI, two sperm selection methods sometimes added to ICSI. Our ICSI page explains when it is used.

What should you ask before paying for an add-on?

The HFEA publishes questions to take to your clinic. These are the ones that matter most:

1. Why are you recommending this add-on for me specifically?
2. What are my chances with standard IVF, and with the add-on? Check whether quoted figures are pregnancies or births, per transfer or per cycle; our guide on how to read IVF success rates can help.
3. What is the evidence, and what is the HFEA rating?
4. Is it safe for me and for my embryos? For tests, ask how often the result is wrong.
5. Will it change my timeline? Some add-ons mean an extra cycle, a freeze-all or extra days in Cyprus.
6. What does it cost, and what is included? Prices for add-ons vary between clinics, so ask for an itemised quote in writing.
7. Would the money go further on another cycle of standard treatment?
8. Does anyone benefit financially from my having it?

Our Cyprus-based team can arrange a free, no-obligation virtual consultation with a recommended partner clinic, where you can go through these questions and receive a written quote for any add-on suggested. Contact us to arrange it.

Do HFEA ratings apply to clinics in North Cyprus?

Not directly. The HFEA regulates UK clinics and has no powers over clinics abroad, including in Cyprus. But the ratings are based on published research, which applies wherever you have treatment, so they are a useful independent check. The HFEA suggests asking any clinic abroad which add-ons it offers and what evidence it has for them. When you compare clinics, ask for each treatment plan to show clearly what is standard and what is an optional add-on.

Frequently asked questions

Are any IVF add-ons rated green?

Not for improving the chance of having a baby, at the time of writing. Some have green ratings for other outcomes: PGT-A for reducing miscarriage, and elective freeze-all cycles for reducing the risk of OHSS.

Is EmbryoGlue worth it for a frozen embryo transfer?

ESHRE's review found a benefit after fresh transfers but no effect after frozen transfers. Ask your clinic why it is suggested in your case.

Should I have PGT-A because I am over 40?

The HFEA rates PGT-A grey for older women, because good-quality studies are lacking, and NICE advises against offering it to improve live birth rates. Discuss it with a specialist who knows your history.

Can I say no to an add-on?

Yes. Add-ons are optional by definition. You can ask for a quote with and without each one.

Sources

• HFEA — Treatment add-ons with limited evidence
• HFEA — UK fertility regulator launches improved ratings for fertility treatment add-ons (2023)
• HFEA — Hyaluronate enriched pre-transfer culture medium (e.g. EmbryoGlue)
• HFEA — Endometrial scratching
• HFEA — Endometrial receptivity testing
• HFEA — Time-lapse imaging and incubation
• HFEA — Assisted hatching
• HFEA — Pre-implantation genetic testing for aneuploidy (PGT-A)
• HFEA — Elective freeze all cycles
• HFEA — Preparing for IVF: questions to ask your clinic about treatment add-ons
• HFEA — Fertility treatment abroad
• NICE NG257 — Procedures used during IVF (2026)
• NICE NG257 — Intracytoplasmic sperm injection (ICSI) (2026)
• NICE NG257 — Rationale and impact (2026)
• ESHRE — Good practice recommendations on add-ons in reproductive medicine (Human Reproduction, 2023)

Last updated: 10 November 2026