In-Vitro Fertilization (IVF), one of the best known treatments for infertility, is recommended to couples that are unable to conceive naturally, and / or when other simpler fertility techniques (for instance, Intra-Uterine Insemination, IUI) have failed.
What is IVF?
Naturally, fertilization of the egg happens in the fallopian tubes of the female reproductive system. In IVF, however, fertilization of the egg happens outside of the body, in the laboratory. To increase chances of fertilization, the procedure starts with ovarian stimulation, which results in the production of more than one mature egg. These are then isolated from the fallopian tubes and mixed with sperm ‘in vitro’, which means ‘in glass’ and refers to the small dishes used in IVF.
The eggs and sperms in the dish are then placed in an incubator that mimics the conditions of the human body, and fertilization is allowed to occur. If a sperm penetrates an egg, they form the first egg-and-sperm hybrid cell that is left to grow in vitro for 2-3 days (2-3-day stage embryos) or up to 5 days (blastocyst stage), before up to 3 of them (in some cases) –the best ones – are selected and transferred back in the womb.
The end goal of an IVF treatment is to have an ongoing, healthy pregnancy followed by a live birth.
Who can benefit from IVF?
Couples that have been diagnosed with unexplained infertility (cases for which we cannot find / define the cause(s) of inability to conceive naturally) can benefit from IVF.
It is a solution for women who have a condition, such as endometriosis, blocked or damaged fallopian tubes. Additionally, for men that have been diagnosed with slightly low sperm quality and / or quantity.
It is also recommended, if you already tried IUI and it was not successful.
How is IVF done?
A procedure of IVF or an IFV cycle comprises of a number of steps.
In a natural cycle, your ovaries normally produce one mature egg that can become fertilized. Stimulating the ovaries with fertility drugs to produce more mature eggs in a cycle is the first step of IVF. This is required because having more than one mature egg offers a much higher chance in fertilizing one of them in vitro, increasing your odds of becoming pregnant.
The choice of fertility drugs that will lead to a higher number of mature eggs in a cycle is tailored according to your individual circumstances.
In most cases, it starts with suppression of the natural cycle, usually by administration of a group of drugs called pituitary agonists or antagonists.
Following, we administer stimulating hormone injections for 9-11 days. These include the gonadotropins, Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH), which drive the ovarian sacs, or follicles, to produce and release more than one mature egg at the same time.
Throughout this process, we closely monitor your ovaries through ultrasound trans vaginal scans and check your hormone blood levels (mainly the hormone estradiol), which can confirm the number of eggs and their level of maturation. Our aim is to obtain 8-12 eggs.
Once this stage is reached, complete maturation of the follicles is achieved with injection of the hormone human chorionic gonadotropin (hCG), which drives the eggs to their final maturation stage.
In cases that we use pituitary antagonists for the suppression of your natural cycle, we can trigger final follicular maturation with Gonadotrophin Releasing Hormone (GnRH) agonist injection rather than with hCG. With this method, we decrease the risk of triggering Ovarian Hyperstimulation Syndrome (OHSS).
For completion of this stage of IVF treatment, 3-5 visits to our facilities, in AAFC, will be required.
Egg collection: It usually takes place 36 hours after the final maturation (hCG injection). During this time, the eggs have reached the optimum stage for fertilization.
Egg collection is performed by a doctor, with the use of a fine, hollow needle using ultrasound guidance and conscious sedation for prevention of any discomfort. It takes around 20-30 minutes to be completed, and after a recovery time, of up to 3 hours, you can return home. The next day you can resume your daily activities as normal. During recovery time, our medical staff will monitor you, checking whether you are experiencing any discomfort. You may be prescribed with a painkiller before being discharged.
Sperm collection: While the eggs are collected, the husband will need to provide a fresh sample of semen. If he is unable to attend at the clinic, freezing his sperm, so it can be thawed and used on the day, will have to be pre-arranged.
The preparation of semen for fertilization is performed by an embryologist in the laboratory. The sample is first washed for removal of excess material and after a brief quality assessment, the best sperms are selected for mixing with the eggs in a dish. Following, they are placed either in a conventional incubator or the EmbryoScope® time-lapse imaging system.
Fertilization: After the first day of combining the eggs and the sperm in a dish, the embryologist performs a microscopic examination to check whether any of the eggs have been fertilized. Fertilization normally happens within 16-20 hours (usually around 18 hours). The eggs that they have been fertilized are the very early embryos, consisting only of a few cells. If they are growing in a conventional incubator, they are checked microscopically at certain time points up until they reach the 2-3-day stage. In some cases, their progress is followed for a bit longer, until they reach the blastocyst stage (5-6-day embryos).
If eggs and sperms are placed in the EmbryoScope® incubator, the early embryos can be monitored through the time-lapse imaging system without being removed from their controlled environment for microscopic observation.
The events of normal early embryo development for the first five days include:
Day 0: Day of the egg collection, when eggs and sperms are put together (IVF or IVF with Intra-Cytoplasmic Sperm Injection, ICSI)
Day 1: Fertilization: The fertilized egg is characterized by the presence of 2 Pro-Nuclei (2PN stage), one from the egg and one from the sperm.
Day 2: Cleavage stage: Normal embryos undergo cell division resulting in 2-4 cells at day 2. The number of cells, cell-shape regularity and degree of fragmentation are checked for assessment of embryo quality.
Day 3: Cleavage stage: Normal embryos at this stage have 4-9 cells. Depending on the number and quality, embryo transfer can be performed on this day. Embryos that rate highly for quality are selected for transfer. If you are a candidate for Pre-implantation Genetic Diagnostic (PGD) testing, the samples from the embryos will be collected on this day.
Day 4: Morula stage: The cells within the embryo continue to divide and align themselves, resembling a mulberry, or morula in Latin. There are about 12-15 cells at this stage. In natural conception, the morula moves into the uterine cavity.
Day 5: Blastocyst stage: At this stage, the embryo has developed into two structures, the inner cell mass, that becomes the embryo, and the trophoblast layer, which will develop into the placenta.
Embryo transfer: The healthiest 2-3-day embryos, or, in some cases, the healthiest blastocysts (the 5-6-day embryos) are selected and placed back in the womb. The choice between the stage of embryos to be transferred, 2-3-day embryo transfer or blastocyst transfer, relies on your history, age and the quality of the embryos. Our experienced embryologists assess the quality of your embryos by microscopic examination (conventional microscopy /EmbryoScope® time-lapse imaging system), and where required, by a series of sophisticated PGD testing and / or Preimplanation Genetic Screening (PGS). Depending on the reason for such investigations, testing for a genetic condition may be performed, or simply, because there is a gender selection preference.
The procedure of embryo transfer is performed by a doctor, under ultrasound guidance and the use of a fine tube (catheter) that delivers the embryos back into the womb. It is normally a pain-free step that takes about 5-10 minutes to complete without the need for anesthesia or recovery time. The experience of embryo transfer is similar to the mock embryo transfer performed at the start of the IVF cycle.
The number of embryos that will be transferred back in the womb depends form the risks associated with multiple pregnancy for your age. Our specialists may have to recommend elective Single Embryo Transfer (eSET) or euploideSET (eeSET) based on your individual circumstances.
Pregnancy test: After embryo transfer and waiting time of about 10-14 days, a pregnancy test can be carried out for checking whether conception has taken place. During this time, you will continue taking other hormones, usually progesterone, which will thicken the uterine wall (endometrium), making it receptive and supportive of the early embryo.
First pregnancy scan: If a pregnancy has occurred, this is further confirmed with an ultrasound transvaginal scan approximately 14 days after the positive pregnancy test. It is performed by one of our specialist doctors and takes about 5-10 minutes to complete without the need for anesthesia or recovery time. These first scans that check early pregnancy are performed through the vagina (transvaginal), because they provide a highly accurate and defined image in comparison to abdominal ultrasound.
During this scan, we check that the embryo(s) is / are inside the uterus (to rule out ectopic pregnancy) and assess the progress so far. The heart beat is usually visible at this stage.
How successful can IVF be?
The success rate of IVF entirely depends on your individual circumstances and reasons of infertility. It has been proven that younger women have much higher chances of becoming pregnant with IVF. Obtaining good quality eggs, that have not declined in quality due to age, is really important for a successful IVF.
The likelihood of becoming pregnant after an IVF is influenced by maternal age and number of embryos transferred and it can fluctuate from over 70%, if you are younger than 35 years of age and have 2 embryos transferred, to just 2%, if you are over 45 years old*. If you have been pregnant and already had a baby, your chances for a successful IVF are higher.
If you have further questions about IVF, our specialist doctors can provide you with more information and consult you on all available options, depending on your individual circumstances.
* Source of data: Human Fertilization and Embryology Authority (HFEA), UK, 2010 (http://www.hfea.gov.uk/ivf-success-rate.html)