The Patient's Guide to Embryology

Add-on Treatments

What are add-ons?

Add-ons are treatments which are not included as standard with an IVF cycle, but may help to improve success rates.

Many add-on treatments are still experimental with conflicting results, however there are also some which can make a big difference to your outcome. So how do you know which treatments will work for you and which are a waste of time and money?

Are add-on treatments safe?

IVF has been around for less than 50 years so there are still many unknowns, particularly when it comes to add-ons. There is a lot of research happening all over the world to try to improve outcomes and new technology is being developed very quickly, but often there has not been enough time to rigorously test it before it is offered to patients. Considering that it takes around 10 years to bring a new drug to the market, IVF add-ons have moved into the fast lane.

Some add-ons such as ICSI or timelapse incubation have been used for many years and are now considered fairly routine. This has generated a lot of reassuring data about their safety, but IVF is such a new industry that nobody knows whether there are any long-term side effects of add-on treatments that only emerge later in life. Other add-ons such as artificial oocyte activation (AOA) are still considered experimental which means that there is not enough data to say for sure that they are safe to use.

Which add-ons are right for me?

There is no one-size-fits-all solution in IVF. What could be the difference between success and failure for one person may be a waste of time and money for another. Read about the pros and cons of some common add-on treatments below.

It is important to remember that many people have a baby with routine IVF treatment without opting for any add-on extras. Some add-ons are very expensive and it often takes more than one cycle to achieve a successful pregnancy, so if you are paying for your own treatment on a budget it may be more effective to pay for multiple basic cycles as opposed to one very expensive treatment using add-ons.

Timelapse Incubation

What is it: An advanced incubator which grows embryos in a continuously undisturbed environment where cameras take images every few minutes to generate a video.

Pros: Embryos can be checked at any time without disturbing their growth. Can help to select the best embryos and de-select abnormal embryos.

Cautions: May have a negative effect on embryo quality in some labs.

Best for: People with lots of eggs/embryos

Preimplantation Genetic Testing for Aneuploidy (PGT-A)

What is it: A method of checking the DNA health of embryos by taking a biopsy of the cells.

Pros: Rules out embryos which would never be able to make a healthy pregnancy. Reduces the risk of miscarriage.

Cautions: Embryos must be frozen until the results are returned. There is a risk of damage to the embryo or inconclusive results. Can be expensive.

Best for: Women over 38 years old.

Intracytoplasmic Sperm Injection (ICSI)

What is it: A method of insemination by injecting a single sperm into an egg.

Pros: Only requires one healthy sperm cell for each egg. Bypasses the sperm binding interaction.

Cautions: Risk of damage to the egg. May result in a higher number of immature eggs compared to traditional IVF.

Best for: Men with poor sperm parameters. Patients with previous poor/failed fertilization.


What is it: An embryo transfer solution containing high levels of a substance called hyaluronan.

Pros: Can improve implantation rates for some patients. Hyaluronan is a naturally-occurring substance in the body.

Cautions: Some studies have found no difference in success whether EmbryoGlue is used or not.

Best for: People who have had failed implantation in the past.

Endometrial Receptivity Array (ERA) Test

What is it: Taking a biopsy of the uterus to check whether implantation genes are being expressed. This gives an optimal window of implantation which can be used to plan an embryo transfer.

Pros: Diagnoses the uterus as receptive, pre-receptive or post-receptive which provides a personalised embryo transfer window that can improve the chance of getting pregnant.

Cautions: Biopsy procedure can be uncomfortable. Delays treatment by at least one month.

Best for: People with previous failed implantation.

Artificial Oocyte Activation (AOA)

What is it: A calcium-based solution added to eggs after being injected with sperm which mimics a boost of calcium normally triggered by sperm during fertilization.

Pros: Can improve fertilization and blastocyst development for some people.

Cautions: Not enough research to confirm safety. Requires ICSI insemination.

Best for: People with previous failed/low fertilization or failed blastocyst development.

Assisted Hatching

What is it: Artificially making a hole in the shell surrounding an embryo, usually with a laser.

Pros: Can help the embryo hatch out of its shell which is required for implantation.

Cautions: Prevents the natural process of embryo expansion. Small risk of identical twins.

Best for: Embryos with an abnormally thick outer shell. People with previous failed embryo transfers.

Elective Freeze-All

What is it: Opting to freeze all suitable embryos instead of having a fresh embryo transfer.

Pros: Delaying the embryo transfer by at least one month gives chance for the body to recover from IVF hormone treatment. Reduced risk of OHSS. Improves chance of pregnancy for some people.

Cautions: Delays embryo transfer by at least one month. There may be no embryos suitable for freezing.

Best for: People at risk of OHSS.

Endometrial Scratch

What is it: Making a small scratch in the uterus to stimulate the production of pro-implantation chemicals.

Pros: Can help to improve implantation.

Cautions: Limited/conflicting data on effectiveness. Scratch procedure may be uncomfortable.

Best for: People with previous failed implantation.

Intracytoplasmic Morphologically-Selection Sperm Injection (IMSI)

What is it: Using high power magnification to choose sperm which look the most normal for ICSI.

Pros: Normal looking sperm may be more healthy and produce better fertilization, embryo development and pregnancy rates.

Cautions: Benefits are mostly theoretical only as there is little data to show it works.

Best for: Men with severely abnormal sperm. Patients with previous failed fertilization or failed embryo development.

Physiological Intracytoplasmic Sperm Injection (PICSI)

What is it: A variation of ICSI where sperm are chosen based on their ability to bind to a substance called hyaluronic acid.

Pros: Sperm which can bind to hyaluronic acid are more mature so more likely to produce better outcomes. Possible reduction in chance of miscarriage.

Cautions: Only the same risks associated with ICSI.

Best for: Patients with a history of miscarriage.

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