In Vitro Fertilization
In vitro fertilization (IVF) was the first assisted reproductive technology (ART) developed and is the most commonly used ART procedure. It is effective in overcoming a variety of infertility problems, particularly tubal problems or marked sperm problems.
The IVF patient undergoes a regimen of hormonal stimulation to entice the ovaries to produce multiple eggs, which are retrieved with ultrasound guidance. The eggs or oocytes are inseminated in the culture dish and fertilization is confirmed the next day.
The embryos are incubated in the laboratory for an additional two days and transferred back to the female partner's uterus. The non-surgical transfer is accomplished by loading the embryos into a small catheter, threading the catheter through the cervical canal, and depositing the embryons into the uterus. As many as four embryos are routinely trasferred back to the uterus.
Transferring multiple embryos has improved IVF success rates, as it has been generally observed that only one out of three embryos will implant. The incidence of twinning is thus increased somewhat while the risks of triplets or quadruplets remains low. Couples having more embryos than intended for transfer have the option of freezing additional embryos for future use.
Intracytoplasmic Sperm Injection (ICSI)
ICSI is a micromanipulation procedure involving the injection of a single sperm into an egg (oocyte) to allow fertilization to occur in the laboratory.
After fertilization, the embryo is allowed to grow for a short period of time before it is transferred to the uterus. The procedure was originally developed in Belgium, has proved to be an effective assisted fertilization technique for patients that produce low number of motile sperm in the ejaculate or sperm that fail to fertilze oocytes following conventional in vitro insemination.
- A motile sperm is captured in a glass injection needle
- The oocyte is held by a glass holding pipet through gentle suction.
- The injecton needle pierces the oocyte and the single sperm is injected into the cytoplasm.
- The injection needle is withdrawn from the oocyte and the sperm decondenses for normal fertilization to proceed.
This is a form of embryo micromanipulation whereby a hole is artificially produced in the embryo's covering, which may increase the chance of embryo development. Selective assisted hatching may increase the chance of pregnancy in certain patients (for example, women with a history of implantation failure or in women with embryos having a thick zona pellucida).