In vitro fertilization (IVF) is an option for many couples who cannot conceive through conventional therapies. In IVF, fertilization occurs outside of the woman's body. Eggs and sperm are united in the laboratory. Once fertilization occurs, the early embryos are transferred to the woman's uterus. IVF was initially developed to assist women who had blocked, damaged, or absent fallopian tubes.
Today patients may be candidates for IVF if they have infertility due to any of the following conditions:
- Tubal blockage or failed tubal reversal
- Endometriosis
- Cervical factor
- Pelvic adhesions
- Male factor
- Unexplained infertility
- Failed conventional therapy.
To be considered for IVF, a woman must have either a uterus capable of carrying a pregnancy, or a compassionate gestational carrier.
For optimal outcome, a woman should not be more than 20 % over her ideal body weight. The IVF process involves stimulation of a woman's ovaries through daily hormone injections. Ovarian response is monitored carefully through frequent bloodwork and ultrasound. When ovarian stimulation is complete, eggs are retrieved from the ovaries using transvaginal ultrasound guidance.
The egg retrieval is performed in the IVF Operating Room under light anesthesia. Patients are discharged home later that same day. Eggs and sperm are combined in the laboratory on the day of egg retrieval. Over the next two days, the fertilized eggs go through the process of cell division. On the third day after egg retrieval, embryos are transferred to the woman's uterus.
Depending on the woman's age, two to four embryos are usually transferred. Any high quality embryos not transferred will be frozen at the time of transfer. Pregnancy test is done eleven days after embryo transfer.
Blastocyst Transfer
With blastocyst transfer, it is possible to transfer advanced stage embryos into the uterine cavity, which duplicates what happens in nature.
Implantation rates for blastocyst transfer are higher than for transfer of early stage (i.e., day 2 or 3) embryos. In part, the increase in implantation rates is due to the duplication of normal reproductive physiology. In addition, better quality embryos may be selected for transfer when embryos are cultured to the blastocyst stage. Culturing embryos to the blastocyst stage results in about half the number of embryos available for transfer as is available on days 2 and 3. However, the decrease in the number of available embryos is offset by the increase in implantation efficiency. The increase in implantation rate decreases the number of embryos that are usually transferred to two, decreasing the rate of multiple pregnancy, especially "high order" (i.e., more than two) multiple pregnancies.
Intracytoplasmic Sperm Injection (ICSI)
ICSI is a procedure in which a single sperm is injected directly into the egg. ICSI is currently the most successful form of micromanipulative assisted fertilization available for male factor infertility. On average, of all the eggs collected, about one-half fertilize normally after the ICSI procedure. Embryos resulting from the ICSI procedure are treated identically to those that arise following conventional IVF.
