Assisted Reproductive Technologies

The most commonly used type of ART is assisted insemination (also known as artificial insemination). With assisted insemination, sperm is obtained from the male through masturbation and then placed in the woman's vagina, cervix, or uterus with a syringe or similar device. Assisted insemination is used to overcome medical conditions that interfere with the ability of sperm to reach and fertilize an egg.

In-vitro fertilization (IVF), a more complex and expensive procedure than assisted insemination, is used for a variety of diagnoses, including unexplained infertility. With IVF, physicians surgically retrieve eggs from the woman's body (in most cases, following a series of hormonal treatments that stimulate the production of multiple eggs), fertilize the eggs in a petri dish, culture the resulting embryos in the laboratory for several days, and then transfer some or all of the embryos back into the woman's uterus for implantation.

Two procedures related to IVF are gamete intrafallopian transfer (GIFT) and zygote intrafallopian transfer (ZIFT). With GIFT, as with IVF, physicians remove eggs from the woman's body, but instead of fertilizing the eggs in a petri dish they transfer the unfertilized eggs, along with sperm, back into the woman's fallopian tubes. With ZIFT, the eggs are fertilized in a petri dish before they are transferred, but instead of transferring the embryos directly into the uterus (as they are in IVF), the embryos are inserted into the fallopian tubes. GIFT and ZIFT were developed as potentially more effective alternatives to IVF, but since success rates with IVF have improved, the popularity of GIFT and ZIFT has declined.

The likelihood that IVF, GIFT, or ZIFT will succeed varies considerably, depending on factors such as the woman's age, the nature of her infertility, and the skills and experience of the practitioners performing the procedures. In 1999, approximately 25 percent of these procedures led to a live birth (Center for Disease Control and Prevention 2002).

IVF is sometimes performed in conjunction with intracytoplasmic sperm injection (ICSI), a procedure in which fertilization is achieved by injecting a single sperm directly into each egg. Because only a few normal sperm are required to perform the procedure, ICSI can be used for men who have poor-quality sperm or extremely low sperm counts. The first successful pregnancy resulting from ICSI was reported in 1992, marking a milestone in the treatment of male infertility.