Assisted reproductive technologies (ART) are a collection of procedures that can assist a woman in becoming pregnant.
Assisted reproductive technologies are used to help fertilize ova (eggs) with sperm, to transplant a fertilied ovum into a women's womb, and to help people hoping to have children overcome infertility or other barriers.
Types of assisted reproductive technology (ART)
Common methods of ART include:
- In vitro fertilization (IVF) means fertilization outside of the body. IVF is the most effective ART. It is often used when a woman's fallopian tubes are blocked or when a man produces too few sperm. Doctors treat the woman with a drug that causes the ovaries to produce multiple eggs. Once mature, the eggs are removed from the woman. They are put in a dish in the lab along with the man's sperm for fertilization. After 3 to 5 days, healthy embryos are implanted in the woman's uterus.
- Zygote intrafallopian transfer (ZIFT) or Tubal Embryo Transfer is similar to IVF. Fertilization occurs in the laboratory. Then the very young embryo is transferred to the fallopian tube instead of the uterus.
- Gamete intrafallopian transfer (GIFT) involves transferring eggs and sperm into the woman's fallopian tube. So fertilization occurs in the woman's body. Few practices offer GIFT as an option.
- Intracytoplasmic sperm injection (ICSI) is often used for couples in which there are serious problems with the sperm. Sometimes it is also used for older couples or for those with failed IVF attempts. In ICSI, a single sperm is injected into a mature egg. Then the embryo is transferred to the uterus or fallopian tube.
ART procedures sometimes involve the use of donor eggs (eggs from another woman), donor sperm, or previously frozen embryos.
Donor eggs are sometimes used for women who can not produce eggs. Also, donor eggs or donor sperm is sometimes used when the woman or man has a genetic disease that can be passed on to the baby. An infertile woman or couple may also use donor embryos. These are embryos that were either created by couples in infertility treatment or were created from donor sperm and donor eggs. The donated embryo is transferred to the uterus. The child will not be genetically related to either parent.
Your doctor will discuss each of these procedures with you so that the most appropriate procedure for your individual situation will be used.
Success Rates for Assisted Reproductive Technology (ART)?
Success rates vary and depend on many factors. Some things that affect the success rate of ART include:
- The age of the partners. (success rates are lower for older individuals)
- The reason for infertility
- The specific linic performing the procedure
- Type of ART used.
- If the egg or embryo used is fresh
The age of the woman is the most important factor, when women are using their own eggs. Success rates decline as women age, and success rates drop off even more dramatically after about age 37.
Part of this decline is due to a lower chance of getting pregnant from assisted reproductive technology, and part is due to a higher risk of miscarriage with increasing age, especially over age 40.
The U.S. Centers for Disease Prevention (CDC) collects success rates on ART for some fertility clinics. According to the 2006 CDC report on ART, the average percentage of ART cycles that led to a live birth were:
- 39% in women under the age of 35
- 30% in women aged 35-37
- 21% in women aged 37-40
- 11% in women aged 41-42
NOTE: these are average figures and the chances of success for a specific couple will depend upon unique factors.
As of 2002, about 28% of cycles in the United States in which women underwent IVF and embryo transfer with their own eggs resulted in the live birth of at least one infant.
This rate has been improving slowly but steadily over the years. For example, the corresponding national rate for 1989 was only 14%.
The delivery rate or "take home baby rate" is the only real measure of success. Patients should be aware, however, that some clinics define "success" as any positive pregnancy test or any pregnancy, even if miscarried or ectopic. These "successes" are irrelevant to patients desiring a baby. To put these figures into perspective, studies have shown that the rate of pregnancy in couples with proven fertility in the past is only about 20% per cycle. Therefore, although a figure of 28% may sound low, it is greater than the chance that a fertile couple will conceive in any given cycle.
Success rates vary with the number of embryos transferred. However, transferring more and more embryos at one time does not continue to increase the chance of success, but may only increase the risk of a multiple pregnancy, which are much more complicated than a singleton pregnancy.
The impact of the number of embryos that are transferred on success rates also varies with the age of the woman. For example, for many women under 35 years of age, transferring more than two embryos does not increase the chance to get pregnant, but only increases the risk of multiple pregnancy.
Presently, the collection of oocytes, fertilization, and early embryo growth are accomplished with a high degree of efficiency. The major hurdles to success are implantation after embryo transfer and early pregnancy loss. All the factors that influence the potential of embryos to implant and produce successful pregnancies are not fully understood. The rate of early pregnancy loss is slightly, but not significantly, higher with assisted reproductive technologies compared to spontaneous conception.
Risk of assisted reproductive technologies?
Pregnancy complications, such as premature birth and low birth weight, tend to be higher with assisted reproductive technology pregnancies, primarily because of the much higher rate of multiple pregnancy. About 30% of assisted reproductive technology deliveries are twin deliveries, versus 1-2% of spontaneous pregnancies. The risk of more than a twin delivery is less than 5%.
There is no evidence chromosome abnormalities (such as Down syndrome) is any different with assisted reproductive technologies than with natural conception.
However, recent research by the Centers for Disease Control showed that ART babies are two to four times more likely to have certain kinds of birth defects. These may include heart and digestive system problems, and cleft (divided into two pieces) lips or palate. Researchers don’t know why this happens. The birth defects may not be due to the technology. Other factors, like the age of the parents, may be involved. More research is needed. The risk is relatively low, but parents should consider this when making the decision to use ART.
ART can be expensive and time-consuming. But it has allowed many couples to have children that otherwise would not have been conceived.