Assisted reproduction refers to a number of advanced techniques that aid fertilization. These techniques are often used for women who have irreversible damage to their fallopian tubes or cervical mucous problems. It can also benefit couples with unexplained infertility.
IVF is the most well known of assisted reproduction techniques. In this method, the woman takes fertility drugs to stimulate her ovaries to produce more eggs. The physician then retrieves one or more of the eggs by laparoscopy or by passing a needle through the vaginal wall. The partner's sperm is then mixed with the eggs in a petri dish, and fertilization may take place.
If fertilization occurs, the embryo is allowed to develop outside the womb for a few days. Then it is implanted in the lining of the woman's uterus with a small plastic tube. Most centers now place two to four embryos in the womb in the hope that one will burrow into the lining and begin to develop normally. Any leftover embryos are frozen to be used later, should the first IVF procedure fail to work. IVF increases the risk of multiple births.
An estimated 45,000 children in the U.S. have been born as a result of in vitro fertilization since 1983.
The Centers for Disease Control and Prevention in Atlanta, Georgia, studied nearly 36,000 in vitro procedures at 300 clinics nationwide and reported on their findings in 1999. They found that about 10,000 births resulted from the procedure. Women with the highest success rate (43%) were ages 20-29 years and had two embryos transferred.
In a variation of IVF called ovum transfer, a donor egg is fertilized with the partner's sperm and then placed in the woman's uterus. This technique is often used when the woman has not been able to produce eggs, even with fertility drugs.
The effectiveness of IVF has improved in the past few years but the chance of pregnancy is still only 20 to 40 percent. It costs as much as $12,000 and usually is not covered by insurance, although some states require coverage of infertility treatment.
In this method of assisted reproduction, the woman's eggs are retrieved but not fertilized. Instead, they are mixed with the man's sperm and immediately placed into the woman's fallopian tubes. The woman must have healthy tubes for GIFT to work.
ZIFT involves placing the fertilized egg itself into the fallopian tubes. This procedure can be more successful than GIFT because the doctor has a greater chance of ensuring that the egg is fertilized. Again, the woman must have healthy tubes for ZIFT.
In this technique, a single sperm is injected into the egg, and the embryo is placed in the fallopian tubes or uterus. This method is often recommended when the male partner has very few sperm or other fertilization methods are not suitable for the couple.
In a new method known as FASIAR, the physician punctures the follicle, and then removes the eggs with a syringe that also holds the sperm. This mixture is then immediately injected back into the follicle. FASIAR may reduce the risk of multiple births and is less expensive than other procedures.