New research has found that mosaic embryos, currently ruled out for IVF selection, could self-correct and lead to healthy pregnancies.

During embryo selection, a test known as preimplantation genetic testing for aneuploidy (PGT-A) is used to screen aneuploid embryos which have an incorrect number of chromosomes. This is performed to reduce the risk of miscarriage.

Embryos with the correct number of chromosomes are called euploid and have a higher chance of leading to a successful pregnancy than those with the incorrect number of chromosomes or aneuploid embryos.

What are mosaic embryos?

Previously, embryos were categorised as normal or abnormal, but in the mid-2010s, embryologists discovered that blastocysts aren’t necessarily 100% euploid or 100% aneuploid: sometimes they’re a mixture.

The term mosaic embryos were coined to describe embryos that have a mix of normal and abnormal cells. Data suggests that mosaic embryos account for up to 20% of all PGT-A-tested embryos.

Mosaic embryos can have different proportions of normal and abnormal cells and there is a criterion ranging from low-level mosaic where 20 to 40% of the cells are abnormal to high-level mosaic.

What did the study into aneuploid embryos find?

Scientists at the laboratory of synthetic embryology at Rockefeller University, New York found that some aneuploid embryos can self-correct. They transferred embryos that had failed the PGT-A screen into women who’d given their consent. Genetic tests performed a few months later found there were no longer any signs of aneuploidy.

The next stage of the study was to understand how the ‘faulty’ embryos developed. Using human embryonic stem cells, they generated artificial human embryos and studied their development. They found that the proportion of the aneuploid cells decreased and the aneuploid cells that remained were in the outer layer which eventually becomes part of the placenta.

As this research shows, the science behind embryo selection continues to evolve and PGT-A is one tool to help us choose which embryos to transfer. Throughout the process, we provide you with all the information you need to make these important decisions.

For more advice on IVF and embryo selection, call +44 (0) 203 263 6025 to arrange a consultation at Aria Fertility.

The more eggs you freeze, the higher your chance of success is regarding fertilisation. This is because at each stage of the process there is a decrease in the number of eggs that survive to the next one. Dr Anna Carby outlines each stage and how the number of eggs decreases between them.

“The thaw survival rate for eggs is between 80 and 90%. Of that surviving thaw, the fertilisation rate is approximately 60 to 70%. Of the fertilised eggs remaining approximately 40% may be usable in terms of either transfer or freezing as embryos. It can be seen therefore that starting with 20 eggs may result in three or four embryos being produced.

“You must also be aware that occasionally these percentages are lower when it comes to thawing and that it is possible, though far less likely, that no embryos are produced as a result of thawing.”

What should you look for in a fertility clinic?

Dr Carby clarifies how “the skill of your team will contribute to the potential success of treatment if you use your eggs in the future. Speak to as many clinics as you can before deciding which clinic to go to. This usually gives you a good indication as to the level of service and the feel of the clinic and team.

“Find out if your clinic offers investigations before or during your consultation which can cut down on the visits required to the clinic.”

Contact us with any inquiries that you have regarding the egg freezing treatment by calling us on 0203 263 6025 or emailing us at admin@ariafertility.co.uk.

After egg freezing, there are many different paths that you can take. Dr Anna Carby discusses the different possibilities.

How long can I store my eggs after egg freezing?

After the fertility preservation treatment, your eggs will be stored, however, there is a limit. “Currently eggs can be stored for 10 years. However, in some circumstances, you may be able to store your eggs for up to 55 years.”

Interestingly, though, this limit has been extended in view of COVID-19.

What would I need to do to use my eggs in the future?

“The process of preparing for an embryo transfer is easier than the stimulation and egg collection required for egg collection. Usually, either oestrogen tablets or patches are used to build up the womb lining for approximately two weeks.

“If the lining looks thick enough on the ultrasound scan, progesterone is then used before embryo transfer to synchronise the lining to the age of the embryo generated,” Dr Carby explains. “This usually means starting progesterone on the day eggs is thawed. These medications then need to be continued until 12 weeks of pregnancy after which time they can be stopped.

“Once eggs have been thawed, they are injected with sperm using a process called ICSI (intracytoplasmic sperm injection) as the normal layer of surrounding cells is stripped before freezing to allow rapid colling of the eggs.”

What if I don’t use my eggs?

Egg freezing is often chosen as insurance, but what if you find you don’t need to use those eggs in the future?

As Dr Carby elaborates, “only approximately 10% of women freezing their eggs ever use them. This is because some will get pregnant naturally when they find a partner or others may decide they don’t wish to use them.”

Contact us with any queries that you have regarding the egg freezing treatment by calling us on 0203 263 6025 or emailing us at admin@ariafertility.com.

There are many reasons why women decide to freeze their eggs and advances in egg viability once they have thawed means this procedure is becoming increasingly popular. However, there is a lot to consider in order to prepare for egg freezing, both mentally and physically, before you enter treatment.

How do I prepare for egg freezing mentally?

The consultation is an important part of the process to ensure you are happy with the clinic’s techniques and protocols. This is because there are two different sets of risks associated with egg freezing.

As Dr Anna Carby explains, “generally the chances of a significant complication with egg collection are less than 1% – these risks are infection, bleeding and damage to the pelvis.
Another condition called ovarian hyperstimulation can occur when the ovaries are stimulated for treatment such as egg freezing.”

However, it is important to note that “in the vast majority of cases this is avoidable by using specific protocols and medications with careful monitoring of treatment cycles.”

Therefore, it is crucial to ensure that you discuss your clinic’s approach to treatment with your clinic so that they can assess whether you are at higher risk of this happening.

How do I prepare physically?

Your ovarian reserve can be affected by several factors. Firstly, however, it is important to understand exactly what an ovarian reserve is.

Dr Anna Carby describes it as “the capacity for your ovaries to respond to stimulatory drugs and is generally measured with hormonal testing and an internal ultrasound scan looking at the ovaries and specifically the number of small follicles in each ovary – known as antral follicles.”

“Before going through egg freezing your doctor will make an assessment as to your general health. Your BMI is important as the process usually involves some sedative drugs through your veins. If your BMI is high (35 or over) you may need to lose weight before going through this process.”

“There are no specific dietary requirements ahead of treatment but wherever possible be as healthy as you can – eat a varied diet, try to do some regular exercise and although you can drink when doing egg freezing it is sensible to have no more than the recommended daily amount and not to have alcohol in the days immediately before and after egg collection.”

Contact us with any questions you have regarding the preparation for the treatment by calling us on 0203 263 6025 or emailing us at admin@ariafertility.com.

Ovarian reserve testing is an important process in successful fertility treatment. Dr Anna Carby explains exactly what this is.

What is ovarian reserve testing?

“You will frequently see this term referred to in fertility clinics. This is the capacity for your ovaries to respond to stimulatory drugs and is generally measured with hormonal testing (particularly AMH – anti-Mullerian hormone testing) and an internal ultrasound scan looking at the ovaries and specifically the number of small follicles in each ovary – known as antral follicles.

“In general, the higher the AMH and the total number of antral follicles, the higher the expectation that the ovaries could respond to stimulation.”

What does this tell me about my natural fertility?

Dr Carby points out that “your ovarian reserve has little bearing on your ability to conceive naturally and cannot be used as a marker of this. Generally, the tests performed for egg freezing do not tell us anything about whether your tubes (fallopian tubes) are open or damaged. Ovarian reserve testing is only used as a marker of response in assisted conception treatments such as IVF and egg freezing.”

Does anything change my ovarian reserve?

There are a few elements that can change your ovarian reserve, as Dr Carby reveals: “Ovarian reserve will get lower with age – this is a natural biological process. In addition to this, smoking is known to affect ovarian reserve. Whilst it is possible to undergo egg freezing if you smoke the outcome you may gain from treatment may not be as good.

“In addition, some contraceptives such as the Pill and some coils such as the Mirena coil can lower ovarian reserve. Depending upon how urgent egg freezing is it may be sensible to repeat ovarian reserve testing a few months after stopping or removing devices. Some studies suggest an up to a 20% decrease in ovarian reserve with contraceptives. Currently, there are no medications known which can improve ovarian reserve.” 

To arrange a consultation with Dr Carby to discuss further or organise ovarian reserve testing call us on 0203 263 6025 or email us at admin@ariafertility.com.

There are many different considerations as to why you might decide to have your eggs frozen.

As Dr Anna Carby explains, “you may be single or in a relationship but perhaps not sure that you want to start a family at this moment or indeed ever. Perhaps you have a medical or surgical problem that may threaten your fertility – ranging from cancer to a family history of periods stopping early or other conditions that require medication that may alter the function of your ovaries. You may be transitioning and want to freeze eggs before undergoing surgery or hormonal treatment affecting your fertility.”

What must be considered prior to egg freezing?

“The success of egg freezing is related to the age at which eggs are frozen. Generally, the success rates with egg freezing start to fall after the age of 34 and therefore ideally it is good to freeze eggs before this time in your late twenties or early thirties.

“However, the actual age at which you freeze eggs may well be related to factors you can’t predict – relationship breakups, medical and surgical issues, gender issues. It is really important to talk to your doctor about the chances of success with treatment.”

Dr Anna Carby also explains what physical assessment might be made. “Your BMI is important as the process usually involves some sedative drugs through your veins. If your BMI is high (35 or over) you may need to lose weight before going through this process.”

If you are contemplating whether you should freeze your eggs, Dr Anna Carby can discuss the process in full with you in a consultation and advise whether you are suitable for egg freezing. To arrange a consultation with Dr Carby to discuss your fertility journey call us on 0203 263 6025 or email us at admin@ariafertility.com

Egg freezing is a great option if you’re considering fertility preservation. At Aria Fertility clinic, we will devise a specific protocol for you, bespoke to your needs.

Dr Anna Carby is one of our fertility experts, specialising in fertility preservation, and she details what you can expect. “One of the more common protocols, called the antagonist protocol, involves starting injections of a hormone called FSH (follicle-stimulating hormone) on day two or three of a cycle.

“After around five days of injections, the second injection of medication is introduced (known as an antagonist) which prevents the release of eggs ahead of collection. Once sufficient follicles of large enough size are reached, then a final injection called a trigger injection is used approximately 36 hours before egg collection.

“This enables the eggs to make their final divisions so that they can be collected. The collection is normally transvaginal (internal) with an ultrasound scan.”

Dr Carby explains how many scans you can then expect during your egg freezing treatment. “During treatment, you will normally need anything between three to five scans to monitor the progress of your follicles. This may alter according to how your ovaries are responding.”

How long can I freeze my eggs?

After freezing your eggs, currently, they can be stored for 10 years. If you suffer from premature infertility – for example, if you have had cancer treatment that has stopped your periods – then in some circumstances you may be able to store your eggs for up to 55 years.

Dr Anna Carby is a highly regarded fertility expert and consultant gynaecologist. She has a specific interest in surrogacy and egg donation. She is passionate about fertility preservation for both medical and social indications and is extremely experienced in carrying out IVF on patients and aiding egg donations.

To arrange a consultation with Dr Carby to discuss your fertility journey call us on 0203 263 6025 or email us at admin@ariafertility.com.