What are IVF and ICSI?

These are two fine laboratory techniques to fertilise the eggs either with either partner or donor sperm. The eggs are harvested from the ovaries in a natural cycle or following controlled ovarian stimulation with hormones.

The fertilised eggs are then kept in special incubators to develop into embryos, and transferred into the uterus on day 2 or 3 of development (known as cleavage stage) but more often on day 5 or 6 of development (known as blastocyst stage).

Who are IVF and ICSI recommended for?

What are the IVF and ICSI steps?

The cycle of treatment includes the following steps or procedures:
  • Taking hormone medications to grow multiple follicles and to collect multiple eggs.
  • Undergoing ultrasound scans, and in some cases blood tests, to assess the ovarian response.
  • Taking the trigger hormone injection 34-36 hours before egg retrieval.
  • Retrieval of eggs from the ovaries under ultrasound guidance and sedation in theatre.
  • Fertilization of eggs with sperm by IVF or ICSI in the laboratory.
  • Growing the fertilized eggs to embryos in the laboratory.
  • Transfer of one or more embryo(s) into the uterus in theatre, usually without sedation.
  • Taking hormone medications whilst waiting to have the pregnancy test.

What is the difference between IVF and ICSI?

In IVF, the eggs and sperm are left in a plastic dish placed within an incubator in the laboratory to fertilise on their own. The eggs are not stripped of the surrounding cells so it is not possible the determine if they are mature or not. 

In ICSI, the selected sperm is directly injected into the egg. The cells around the eggs are removed prior to the injection, and each egg is individually assessed to confirm maturity for the ICSI procedure to take place. Only mature eggs are injected with sperm. 

Both the inseminated and the injected eggs are then placed within an incubator in the laboratory until the following day when the embryologist check for signs of fertilisation.

Treatment Process FAQs

In most cases stimulation of the ovaries is recommended to collect multiple eggs. The stimulation requires hormone injections that contain follicles stimulating hormone (FSH) with or without luteinising hormone (LH), and are usually started at the very beginning of your menstrual cycle or an induced bleed. The dose and type of hormones is patient specific and depends on various factors, including age, body mass index, anti-Müllerian hormone (AMH) levels, antral follicle count (AFC), response to previous ovarian stimulation protocols, if available. 

Injections should be administered by yourself at the same time every day.

The injections are administered for a period of 10 to 14 days, depending on the ovarian response. Once your follicles have reached their optimal size, your consultant will prescribe the ‘trigger’ injection to ensure the eggs within your follicles mature and the eggs are ready for harvesting 34-36 hours later. 

After 5 or 6 days of you taking the hormone injections, you will be having transvaginal ultrasound scans every 2 or 3 days. This is important to determine the development of the follicles, to alter the dose of the medications to ensure adequate response as much as possible, and to decide when to have the ‘trigger’ injection in preparation of the egg retrieval. Biochemistry (blood) tests are performed sometimes in conjunction with the ultrasound scans to better assess the response to the ovarian stimulation hormones. 

This procedure is performed in the theatre room, generally adjacent to the laboratory, and you will be given sedation medications via an intravenous line. An anaesthetist and nursing staff will be present in theatre together with the consultant. If necessary you may be given pain relief during the procedure or afterwards. 

The egg collection takes 15-30 minutes depending on the number of follicles available and the difficulty to access the ovaries. A fine needle, sliding into a guide mounted on the transvaginal ultrasound scan probe, is inserted through the vagina into the ovaries, and the fluid of each follicle is aspirated into a clear tube which is then passed to the embryologist to look for the egg. 

Very seldom absorbable stitches may be put inside the vagina at the end of the procedure, if there is a small area of bleeding. You will be able to resume normal activities the following day.

The sperm that will be used to inseminate the harvested eggs is received either from your partner fresh in the morning of your egg collection or if frozen will be thawed and processed to make it ready for insemination. If you are using donor sperm, this will be thawed and processed on the day of egg retrieval.

After checking for fertilisation, the embryologists either directly or by means of time lapse technology inspect the embryos development over the next few days. Embryos are kept in special culture media solution and in controlled incubators to aid development.

In chronological order, below are the steps from fertilisation to blastocyst formation:

  • Day 1: The inseminated or injected eggs are assessed for fertilisation. 
  • Day 2: The fertilised eggs start to divide in to multiple cells and become embryos. Most of the embryos have between 2 to 4 cells at this stage.
  • Day 3: The embryos have developed further, and have between 6 to 8 cells at this stage. They can be chosen for transfer or left in culture for further development.
  • Day 4: No evaluation of the embryos occurs at the Morula stage, but information can be gained if using time lapse systems.
  • Day 5: The embryos have reached the Blastocyst stage, and are suitable for transfer if planning a fresh embryo transfer or alternatively can be frozen for future use. Any embryos that may not have yet reached the Blastocyst stage are cultured further for possible freezing later on the same day or the following day (day 6). 

This procedure does not require any anaesthesia, unless you prefer so or it has been difficult in the past. The embryologist selects the best embryo(s) for transfer. It is performed in a dedicated procedure room close to the laboratory. Some women only may feel mild discomfort. 

The practitioner inserts the speculum in the vagina (similar to taking a smear test), then clean the vagina before inserting a catheter through the cervix and into the uterus to place the embryo(s) under ultrasound guidance. You will require to have a full bladder. 

After the procedure, women may experience some light cramping, and very occasionally spotting and vaginal discharge. We recommend taking it easy, avoid exercise, sexual intercourse, hot baths, saunas, steam rooms, swimming, smoking and drinking alcohol. Make sure you are taking your folic acid and other supplements as recommended by your consultant. Follow the instructions of your fertility team if you are taking hormones. Your pregnancy test will be done circa 12-15 days after your embryo transfer, depending on you having had blastocyst or cleavage stage embryo transfer. 

Both IVF and ICSI have been around for over three decades and over 2.5million treatment cycles are performed every year globally. Published data in the literature show that the chances of success either as clinical pregnancy rate or live birth rate depend on several factors such as female chronological age, number and quality of eggs, quality of sperm, quality of embryos, previous pregnancies and live births as well as lifestyle. However the live birth rates in good prognosis patients can be as high as 50-55% per cycle, with no significant difference between fresh and frozen embryo transfers.

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