In vitro fertilizaiton (or IVF) is a reproductive technology in which eggs are removed from the ovaries and joined with sperm outside of the body in order to form embryos. These embryos are then transferred back into the woman, or in some cases, a gestational carrier.
An In Vitro Fertilization (IVF) IVF cycle consists of four basic steps:
- Ovarian stimulation
- Egg retrieval
- Fertilization and embryo development
- Pre Implantation Genetic Screening (elective)
- Embryo transfer
During the ovarian stimulation phase, medications are administered to stimulate the ovaries to produce multiple eggs. The eggs are then retrieved under mild anesthesia using a small needle that is inserted through the vaginal wall into the ovaries. The eggs are then fertilized with sperm in the laboratory. Embryos are typically grown in incubators for 5-6 days. Embryos that appear to be of good quality can then be transferred back into the uterus, cryopreserved (frozen) or biopsied and frozen so that genetic testing can be performed.
When semen has moderate or severe defects, we recommend treatment with a process of micromanipulation called intracytoplasmic sperm injection (ICSI). The embryologist, under microscopy, injects a single sperm into each mature egg retrieved. This technique greatly increases the chances that fertilization will occur.
Some patients will decide to analyze their embryos for chromosome abnormalities through a procedure called Pre-implantation Genetic Screening (PGS). This technology allows patients to identify chromosomally normal (euploidic) embryos, thereby increasing the chances of pregnancy and reducing the chance of miscarriage with each transfer. Please click here to learn more about the process of PGS. Pre-implantation Genetic Diagnosis (PGD) can also be performed if a patient is know to carry a specific single-gene defect or chromosome translocation.
In the past, embryos were often transferred on Day 2 or 3 of embryo development. With improved culture techniques, embryos today usually grow in extended laboratory culture to Day 5 or Day 6 prior to transfer, freezing or biopsy. An embryo at this stage is known as a blastocyst, so this procedure is called a blastocyst transfer.
By allowing the embryos additional time to develop, we can determine with greater certainty which embryos have the greatest chance of implantation and resulting pregnancy. As a result, fewer embryos need to be transferred, decreasing the chance of multiple pregnancies without compromising your chance of success.
Intracytoplasmic Sperm Injection (ICSI)
The ICSI procedure has dramatically changed the prognosis for patients with moderate-to-severe male-factor infertility. In “conventional insemination”, the egg and sperm are placed in a dish and fertilization takes place there. With ICSI, the embryologist takes a single sperm and places it directly into the egg using a micro-needle. The procedure produces better fertilization rates for these patients than conventional insemination.
In this procedure, a small opening is made in the outer layer surrounding the embryo shortly before it is transferred to the uterus. In some circumstances, this may help the embryo break out of the outer layer of cells (zona pelucida) and increase the likelihood that implantation might occur.