Reproductive Technologies
- Jan 9, 2006 -
There are many terms associated with reproductive technology. The following are a few of the more important ones. Others may be found at the website of the Centers for Disease Control at http://www.cdc.gov/nccdphp/drh/ART99/appixb.htm .
ART (assisted reproductive technology). All treatments or procedures that involve surgically removing eggs from a woman’s ovaries and combining the eggs with sperm to help a woman become pregnant. The types of ART are in vitro fertilization, gamete intrafallopian transfer, and zygote intrafallopian transfer.
ART cycle. A process in which (1) an ART procedure is carried out, (2) a woman has undergone ovarian stimulation or monitoring with the intent of having an ART procedure, or (3) frozen embryos have been thawed with the intent of transferring them to a woman. A cycle begins when a woman begins taking fertility drugs or having her ovaries monitored for follicle production.
Egg transfer (also called oocyte transfer). The transfer of retrieved eggs into a woman’s fallopian tubes through laparoscopy. This procedure is used only in GIFT.
Embryo. An egg that has been fertilized by a sperm and undergone one or more divisions.
Embryo transfer. Placement of embryos into a woman’s uterus through the cervix after in vitro fertilization; in zygote intrafallopian transfer (ZIFT), the embryos are placed in a woman’s fallopian tube.
Gamete. A reproductive cell, either a sperm or an egg.
GIFT (gamete intrafallopian transfer). An ART procedure that involves removing eggs from the woman’s ovary, combining them with sperm, and using a laparoscope to place the unfertilized eggs and sperm into the woman’s fallopian tube through small incisions in her abdomen.
ICSI (intracytoplasmic sperm injection). A procedure in which a single sperm is injected directly into an egg; this procedure is most commonly used to overcome male infertility problems.
IUI (intrauterine insemination). A medical procedure that involves placing sperm into a woman’s uterus to facilitate fertilization. IUI is not considered an ART procedure because it does not involve the manipulation of eggs.
*IVF (in vitro fertilization)). An ART procedure that involves removing eggs from a woman’s ovaries and fertilizing them outside her body. The resulting embryos are then transferred into the woman’s uterus through the cervix.
Miscarriage (also called spontaneous abortion). A pregnancy ending in the spontaneous loss of the embryo or fetus before 20 weeks of gestation.
Multifetal pregnancy reduction. A procedure used to decrease the number of fetuses a woman carries and improve the chances that the remaining fetuses will develop into healthy infants. Multifetal reductions that occur naturally are referred to as spontaneous reductions.
ZIFT (zygote intrafallopian transfer). An ART procedure in which eggs are collected from a woman’s ovary and fertilized outside her body. A laparoscope is then used to place the resulting zygote (fertilized egg) into the woman’s fallopian tube through a small incision in her abdomen.
1999 Assisted Reproductive Technology Success Rates, Appendix B (December 2001) [Accessed August 25, 2005]
For some couples who experience infertility and are incapable of conceiving a child under normal conditions, assisted reproductive technology (ART) may be their only hope. But there should be an awareness of the attendant problems. “There are limits to what science can do for infertile couples, and the more doctors have to intervene with drugs, needles and surgery to get sperm to meet egg, the greater the chance that something will go wrong.” Possibilities suggested are problems related to ovarian hyperstimulation, low birth weight and birth defects. But another is multiple gestation (development of more than one baby). “Not being able to have a baby can be heartbreaking. But having too many at once can be even worse. About 20 percent to 35 percent of IVF pregnancies produce multiple fetuses, usually twins. Having more than two or three babies at once is often a medical disaster. Babies that develop in a crowded uterus or are born too early are at risk for a lifetime of developmental problems, including mental retardation, paralysis and blindness. Trying to reduce the number of fetuses through selective abortion has its own problems, not the least of which is an increased chance of miscarriage.”
“The Limits of Science,” Time, April 15, 2002
A major study, cited in the New England Journal of Medicine, was conducted in Australia which found that birth defects among babies conceived using two assisted reproductive technology methods were twice as high as defects in naturally conceived babies within the first year after birth. The two methods used were intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF). [A brief explanation of these terms are found elsewhere in this fact sheet.] In the ICSI group, twenty-six of 301 infants (8.6 percent) developed birth defects; in the in vitro fertilization group, the ration was 75 out of 837 infants (9.0 percent). For those infants conceived naturally, 168 out of 4000 infants (4.2 percent) were found to have developed birth defects within the first year.
The study found that “there may be an excess occurrence of major cardiovascular, urogenital, chromosomal, and musculoskeletal defects associated with assisted conception.” The study also found that “infants conceived with assisted reproductive technology were significantly more likely to have multiple major defects than the naturally conceived infants.”
“The Risk of Major Birth Defects After Intrcytoplasmic Sperm Injection and in Vitro Fertilization,” New England Journal of Medicine, March 7, 2002
Since 1983, when the first infant was conceived from in vitro fertilization (IVF) in the United States, the use of assisted reproductive technology (ART) has increased substantially. In 1998, an estimated 0.7 percent of the 3.9 million births were the result of ART. ART patients are more likely to deliver multiple infants than women who conceive without treatment, and these multiple-infant births are associated with increased risks for pregnancy complications, premature delivery, low birth-weight infants, and long-term disability among surviving infants.
“Use of Assisted Reproductive Technology: United States, 1996 and 1998,” Journal of the American Medical Association, March 27, 2002
“An embryo is a human being at an early stage of development. It is separate from the portion of the developing group of cells that become the placental or supportive tissue. After the sperm has penetrated the egg and when the chromosomes from the father and mother have aligned in the egg, fertilization has occurred. In a natural cycle, the event takes place in one of the fallopian tubes of the female. …The earliest cells are believed to be ‘totipotential.’ That is, each cell can generate all the tissues necessary for a baby’s development. No genetic material is added after the moment of fertilization. Each individual, from the moment of fertilization represents an individual of tremendous worth, created in the image of God.”
Gary P. Stewart and John F. Kilner, editors, Basic Questions on Reproductive Technology (Grand Rapids: Kregel Publications, 1998), 21-22.