Updated: Dec 14, 2021
This is part two of the three-part blog series discussing the process of IVF. In this blog we discuss the IVF process after egg retrieval. This includes the in-vitro fertilisation process, how embryos develop, the embryo transfer process and what happens after the embryo transfer.
In part 1 we covered the timeline of IVF, preparation for your cycle and ovarian stimulation.
The In-Vitro Fertilisation ( IVF) Phase of the IVF Cycle
Fertilisation and Embryo development
The IVF process after egg retrieval begins immediately. The embryologists go to work by taking the petri dish, mixing the sperm and eggs together and placing them in the incubator overnight to allow them to fertilise.
If there is a small number of sperm, or the sperm is abnormal and sperm has been retrieved surgically, one sperm may be injected directly into each egg. This process is intracytoplasmic sperm injection (ICSI).
The eggs that have fertilised will be counted and the embryologist will check on them at various times to check their development and growth. The embryologist will then call you to tell you how many have fertilised or if any eggs were immature or didn’t fertilise. They will then tell you when they will call you again to provide you with an update on progress.
The embryologists will monitor to check that the fertilised eggs, now called zygotes, are developing into embryos and then into blastocysts. You can read about the process of cell division in the section ‘what is conception?’ in this blog below. You can also see images of the various stages of embryo development on the British Fertility Society website.
It’s highly likely that a number of eggs will not fertilize. This is why it’s ideal to have a good number of eggs (for example 8-15 eggs) that can create a good number of embryos.
If you have 4 or more embryos (or blastocysts) then you will have a good selection to choose from and potentially be able to freeze some for future attempts in the near or distant future. If you want to have the embryos or blastocysts genetically tested before transfer then a good number of embryos to have is around 8-10 or more as the final number you will select from is likely to be much smaller.
Overall a good number of embryos is ideal but only one embryo (or possibly two if you are outside of the UK) is transferred during your first cycle so the aim is to transfer the best quality embryo available and have some for future cycles. This may still be achieved with a smaller selection of embryos and may not always be possible to achieve regardless of the number of embryos. Embryo quality and grading is discussed in a later section.
Embryos can be ready for transfer on day 2 or day 3. They can also be transferred on day 5 which is when they are at the blastocyst stage. The embryologists and your doctor will usually decide the best embryo stage for transfer and discuss this with you. It’s important to be aware that embryos transferred on day 2 or day 3 can also result in a successful pregnancy; your embryos do not have to reach the blastocyst stage. Embryo vs blastocyst transfer will be discussed in the next blog.
The embryologists will call you to let you know when to come in for the embryo transfer and provide you with instructions for the day. You will usually need to drink enough water so that your bladder is full and ready for the transfer.
The Final Phase of the IVF Cycle
This is the day that the embryos are transferred into your uterus.
On the day of embryo transfer, you can usually attend with your partner (COVID restrictions permitting). It’s important that you (and if your partner is also able to attend) arrive clean, avoid applying body lotion, wearing perfume, hairspray, nail varnish or make up.
If you have more than two embryos or blastocysts the embryologist will ask you whether you want to transfer one or two embryos.
The British Fertility Society strongly recommends single embryo transfer but if you are over 35 or have had repeated failed IVF cycles, your doctor may recommend that two embryos are transferred. If you are aged 40 or more and using embryos fertilised from your own eggs, you can have a maximum of 3 embryos transferred.
The single embryo transfer recommendation is on the basis of safety for both the baby and the mother or surrogate because multiple pregnancies (carrying two or more babies) are high-risk pregnancies. Deciding on the stage and the number of embryos to transfer is an important topic so it will be discussed in the next blog. However, this is a discussion that you should have with your doctor and embryologist.
The embryologist will select the best embryo(s) for transfer. They will tell you the grade and quality of the embryo before the procedure begins.
Feel free to ask whether you can play some music during the procedure if that will make you feel comfortable.
You will lie down with your legs on the stirrups. The doctor will insert a tube into your cervix and the embryologists will then bring the fluids containing your embryos in a syringe. This will be attached to the tube and then pushed through the tube into your uterus.
This procedure may or may not be done using an ultrasound scan. In some clinics, you can watch the embryos being injected into your uterus on a TV screen.
After the procedure you will be required to lie for a short period of time, then you will be able to get dressed and leave. There is not usually a requirement to rest or take the day off work.
After The Embryo Transfer
Two Week wait, Pregnancy Test and Follow-Up
Any remaining embryos or blastocysts can be frozen if you have signed consent for this to happen.
After the embryo transfer, you will usually be able to go home or return to work. Your clinic will provide you with instructions for the next steps. You do not need to take a rest period unless you want to do so.
This is the period of waiting often referred to as the ‘two week wait’. This is because you will find out whether or not the IVF treatment has been successful approximately two weeks after your embryo transfer. Your clinic will provide you with a pregnancy test (PT) and ask you to take it on a specific day, which could be between 12-16 days after embryo transfer.
Many women experience heightened feelings such as nervousness, excitement or worry during the two-week wait. It can seem like a long wait to find out whether the treatment has worked. Any symptoms from a twinge of cramping to breast tenderness or even lack of symptoms are questioned.
Some women perform their PTs early and several times before it’s due. Unfortunately, this can lead to misleading results. As much as possible, try to wait until the required day to take your PT. Once you take the PT you should inform your clinic of the result.
During the two week wait, you will be taking progesterone. The progesterone is usually started the day after the egg collection. You may have suppositories, which you should insert into the vagina or your back passage as directed by your clinic or you may be prescribed progesterone injections that need to be injected into your buttock.
Your clinic may want you to have progesterone blood tests to check your progesterone levels. The progesterone and any other medication you’ve been advised to take should continue until you take the PT.
If your PT is positive and you are pregnant you will be advised to continue the medication and the clinic will contact you regarding any further monitoring blood tests e.g. your pregnancy hormone bHCG levels and progesterone levels and ultrasound scans.
If you do not become pregnant you will be asked to stop the medication and an appointment will be made to follow up with the doctor anytime between 2-8 weeks afterwards depending on the clinic.
During the follow-up appointment you will meet with your fertility specialist to discuss the cycle, have any questions answered and discuss options going forward. You do not have to make any firm decisions during the appointment about next steps.
It is natural to not only feel very disappointed, if you do not fall pregnant, but also to feel a huge sense of loss. A failed cycle can feel like losing a baby if you felt pregnant or believed that your embryo was going to become your baby. This can be a period of grieving; and if you feel this way, acknowledge this and give yourself space and time to grieve.
Additionally, you may feel physically tired from your treatment. This combination of grief, disappointment and exhaustion; the physical and emotional effects of infertility can make you feel isolated and alone.
You may find it helpful to get support from someone or a group of people who understand what you are going through and empathise with how you feel. Whether you get help from a trusted friend, a local support group, a health professional, fertility coach or the coaching and concierge service from Your Trusted Squad led by me, Dr Belinda Coker, please do not suffer alone.
In part 3 we will cover the eligibility for NHS funding and the complications of IVF. You can subscribe to be notified of when it’s released and also receive our monthly newsletter.
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