In vitro fertilization (IVF)
In vitro Fertilization
In vitro fertilization literally means ‘fertilized in glass’.
In IVF, eggs are removed from the ovary just before ovulation. The eggs and sperm are then placed together in a specialised laboratory environment.
If fertilization and normal embryo development occurs, the best embryo(s) is/are returned to the uterus (womb) 3-5 days later.
When is IVF used?
IVF was originally developed to treat blocked and damaged fallopian tubes. Now, IVF is used for a wide range of disorders including endometriosis, male factor infertility and unexplained infertility.
How many visits are required for a cycle?
Treatment is monitored using a combination of ultrasound scanning and blood tests. Cycles and individuals vary but 2-5 monitoring visits and 8-12 days of stimulation is usual.
To have a reasonable chance of success, a number of egg follicles need to develop. Generally over half of eggs collected will fertilise and half of these will grow on as embryos.
What are the stages of IVF and ICSI?
Stimulation of the ovaries to produce a number of eggs is key to your treatment. The ovaries are stimulated with Follicle Stimulating Hormone (FSH). The ovaries produce a number of follicles within which eggs will hopefully develop. A number of different fertility drugs and protocols are used in the treatment to control the timing of egg release.
Eggs are microscopic, but they grow in fluid-filled structures called follicles which can be clearly seen on ultrasound scan. The development of the follicles is routinely monitored using vaginal ultrasound scans. After about 7-12 days of the injections, the follicles will almost be mature. Once a number of follicles have matured, an ovulation trigger (hCG) is given and egg collection is scheduled.
This is a minor surgical procedure, carried out at Merrion Fertility Clinic using ultrasound guidance. A Senior Consultant Anaesthetist is present administering sedation and pain relief intravenously for the procedure. Egg collection is performed 36 hours after hCG trigger injection. Ultrasound-guided follicle drainage is performed and the retrieved fluid checked for eggs. An egg is generally retrieved from most mature follicles, but there are no guarantees. The eggs collected are prepared for insemination or injection with sperm.
Before/during the egg collection procedure, the male partner will provide a semen sample that will be specially prepared and used to inseminate the eggs. Alternatively, if frozen sperm is to be used, this will be thawed out.
Merrion Fertility Clinic has strict protocols in place to double-check the identification of samples and the patients to whom they relate at all steps of the clinical and laboratory processes. Every step along the IVF/ICSI process is double witnessed, i.e. 2 members of staff will confirm the patient’s details. For more information on our identity check policy, please see below.
Eggs are inseminated in the afternoon following egg collection (‘Day 0’) and are left overnight to fertilize. Usually, about 60-70% of the eggs collected fertilize, but this can range from 0% to 100%. Regrettably, some 2-3% of couples will not achieve fertilization of any eggs.
There are 2 ways to inseminate eggs.
IVF (In Vitro Fertilization): a fixed concentration of motile sperm (100,000) are mixed with the eggs overnight. During the night the sperm should fertilize the eggs.
ICSI (Intra-Cytoplasmic Sperm Injection): used when there are not enough capable sperm to fertilize the eggs using standard IVF. Eggs are first checked to make sure they are mature as only mature eggs can be injected and subsequently fertilize. An individual sperm is then selected by the embryologist and injected directly into each egg.
Eggs are checked the following morning (‘Day 1’) for fertilization and patients are phoned with the update.
Following fertilization, eggs develop on to the embryo stage. Embryos are cultured or grown in the lab for a number of days.
The aim of embryo culture is to learn about the embryos and determine which are best and most likely to implant in the womb. The day of transfer (day 3 or day 5) is largely determined by the number and quality of embryos in that given cycle.
Currently, over 60% of transfers in Merrion Fertility Clinic occur on day 5. This is called Blastocyst Culture. In some cases, transfer may be recommended on day 3.
The embryo transfer procedure is quite simple and is usually pain-free. No anaesthetic is necessary. A very fine tube (catheter) containing the embryo(s) is gently guided into the uterus. Once inside the uterus, the embryo is then transferred. Ultrasound is used to facilitate the process.
The number of embryos to be transferred will depend on several factors including female age, previous pregnancies and number of cycles. This will be discussed in detail with every couple prior to treatment and again on the day of embryo transfer.
Elective Single Embryo Transfer (eSET) is recommended in circumstances with a high potential for pregnancy. It is well proven worldwide that the safest pregnancy, for both the mother and child, is a singleton pregnancy.
We may transfer two embryos if transferring only one means a significantly lower chance of pregnancy. This way we maintain a good chance of pregnancy while minimising the risks of multiple pregnancies and all associated complications (miscarriage, premature delivery, cerebral palsy, fetal or neonatal death etc).
Rarely, a single embryo does split in two following transfer, resulting in identical twins. The chances of this occurring are very low.
Where circumstances are unsafe or unsuitable for transfer, we freeze all suitable embryos for transfer at a later stage, when conditions are more favorable.
Please be aware that Merrion Fertility Clinic has a single embryo transfer policy – for more information click here.
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Please note that you need a GP or Consultant referral to book a Semen Analysis appointment, but this is not a requirement to book a Doctor Consult.