In Vitro Fertilization (IVF) and how does it work?
What is IVF
In vitro fertilization (IVF) means ‘fertilization in glass’ giving us the familiar term ‘test tube baby’.
During the IVF process, eggs are removed from the ovaries and fertilized with sperm in the laboratory. The fertilized egg (embryo) is later placed in the woman’s womb.
How does IVF work?
IVF techniques can differ from clinic to clinic, often depending on your individual circumstances.
Step 1: Ovulation Induction
Ovulation induction is a process where hormonal fertility medication is administered to help increase the number of eggs produced.
Step 2: Monitoring Progress
Throughout the hormonal treatment, your doctor will monitor your progress. Using ultrasound scans and blood tests to monitor egg development and to to determine likely ovulation.
Step 3: Egg Retrieval
The egg retrieval process is a minor surgical procedure that uses an ultrasonic probe to guide a thin needle through the wall of the vagina into the ovary to collect the mature eggs.
Step 4: Collection and sperm preparation
Sperm collection and preparation are usually done on the day of the egg retrieval. After being collected, the sperm are separated from the seminal fluid to increase the number of mobile sperm and improving the likelihood for fertilization. Sperm collection can sometimes be stressful for a man. For those men, a semen sample can be produced ahead of time and cryopreserved until needed. In some male factor infertility cases, a testicular biopsy can also be performed as a method to collect sperm.
Step 5: Insemination, Fertilization and Embryo Development
Insemination can happen one of two ways during IVF treatment: Conventional Insemination: Where sperm and egg are combined in the embryology lab to allow fertilization, resulting in embryo creation.
Intracytoplasmic Sperm Injection Insemination (ICSI): Where the laboratory injects a single sperm into each egg, greatly increasing the chances that fertilization will occur. This method is chosen when sperm has poor sperm survival, moderate or severe defects and/or a history of poor fertilization from previous IVF cycles.
Fertilization: Twelve to sixteen hours after conventional insemination or ICSI, the sample is examined to confirm that fertilization has taken place. Once this occurs, the fertilized eggs are considered embryos.
Embryo Development: The embryo(s) are then cultured to grow and divide in the laboratory for three to five days before being transferred.
Step 6: Embryo Transfer
Transferring the embryo(s) is the final and most important step in the IVF process. After three to five days following fertilization, one or more embryos are placed into a woman’s uterus. This procedure mimics that of a routine pap smear and has little pain or discomfort associated.
Step 7: Embryo Implantation and Pregnancy Test
Upon completion of the embryo transfer, the embryo(s) should “hatch” from their outer shell and implant into the uterine wall. A blood test is performed to determine pregnancy, typically nine to eleven days after transfer.
Assisted hatching is a procedure that is performed in order to help an embryo hatch out of its outer protective layering. The procedure involves making a small incision into the outer shell just prior to the transfer of the embryo into the uterus. This increases the likelihood that the embryo will implant into the uterine wall, resulting in a successful pregnancy.
Blastocyst Embryo Transfer:
Traditionally, embryos are transferred into the uterus three days after fertilization. If a patient has a large number of embryos and/or the best embryos are not clearly identified on day three, we may suggest waiting two more days and doing a blastocyst embryo transfer. The advantage to waiting two extra days to five days before transfer is that it helps provide more information on the quality of embryos and gives a better choice of which embryos to choose for transfer.
Step 8: Cryopreservation & Embryo Freezing
During the IVF process, sometimes, more embryos develop than are used or transferred. Should this be the case, there is the option to freeze (cryopreserve) any excess good quality embryos for future IVF attempts. Embryos can be frozen at the pronuclear stage (one cell), or at any stage after that up to and including the blastocyst stage (five to seven days after fertilization).
If a patient or couple does not wish to cryopreserve their extra embryos, they may choose to “donate” the embryos.