Add-ons are optional extras some patients have alongside fertility treatment. The Human Fertilisation and Embryology Authority (HFEA), the UK fertility regulator, rates each one with a traffic light, based on the evidence that it improves the chance of having a baby. Read the HFEA’s guide to treatment add-ons.
Most HFEA ratings look at the evidence for patients in general (“most patients”). An add-on that does not help most patients may still help a specific group: for example, PGT-A is rated Red for having a baby across most patients, but Green for reducing miscarriage. Where the HFEA has rated an add-on for a specific group, we show that rating too. Your doctor will only suggest an add-on where there is a clinical reason in your case, and will go through the evidence and the HFEA rating with you first.
- GreenOn balance, high quality evidence shows this add-on is effective at improving the treatment outcome.
- YellowOn balance, it is not clear whether this add-on is effective: moderate/high quality studies conflict.
- GreyThe HFEA cannot rate its effectiveness, as there is not enough moderate/high quality evidence.
- BlackOn balance, moderate/high quality evidence shows this add-on has no effect on the treatment outcome.
- RedThere are potential safety concerns and/or, on balance, moderate/high quality evidence shows it may reduce treatment effectiveness.
- Not ratedNot on the HFEA’s list of rated add-ons.
Embryo testing
PGT-A Genetic Testing
£750Screens embryos for chromosomal abnormalities before transfer, helping reduce miscarriage risk. Priced per embryo.
Womb lining tests and treatments
ERA Test
£1,400Endometrial Receptivity Array — finds your personal window of implantation. Excludes scans and blood tests.
EMMA Test
£1,200Endometrial Microbiome Metagenomic Analysis (includes ALICE) — checks the balance of protective and harmful bacteria in the womb lining.
ALICE Test
£595AnaLysis of Infectious Chronic Endometritis — tests for bacteria linked to chronic endometritis.
EndomeTRIO
£1,750Three tests on one biopsy sample of your womb lining. ERA aims to find your window of implantation; EMMA and ALICE check the bacteria in the lining.
Endometrial Scratch
£250A short procedure that gently scratches the womb lining. It is sometimes offered to people whose embryos have not implanted in previous cycles.
Intralipid infusion
£550Sperm tests, selection and fertilisation
PICSI
Physiological ICSI. Before ICSI, sperm are placed on a dish coated with hyaluronan, a substance found around the egg, and the sperm that bind to it are selected.
pIMSI
Ultra-magnified imaging lets us identify sperm with ideal morphology for better embryo development.
Sperm DNA Fragmentation Test (DFI)
£550A test that measures DNA damage in a sperm sample. It looks at something a standard semen analysis does not show. Ideal for couples with unexplained infertility.
Zymot (Microfluidic Sperm Sorting)
Mimics the body’s natural filtering process, selecting sperm with lower DNA damage and better motility.
SID (Sperm Intelligence for ICSI)
Our proprietary AI grades sperm A–C in real time, guiding embryologists toward the most viable candidate.
SpermMobil
Gives sluggish sperm the energy boost they need to reach the egg and complete fertilisation.
Rescue ICSI
A second-chance procedure performed when eggs don’t fertilise after conventional insemination.
Oocyte Activation
Used when sperm cannot trigger fertilisation naturally, restoring the egg’s full potential.
ICSI SPARK
Avenues-developed innovation enables fertilisation even in cases once considered impossible, supporting egg activation.
HFEA ratings checked 15 November 2026. Prices are per test or procedure unless stated.