Assisted reproductive technology (ART) and pregnancy
What is ART - Assisted reproductive technology
Medical interventions to produce PREGNANCY. The US Centers for Disease Control and Prevention (CDC), which has a mandate under federal law to report the success rates of ART at FERTILITY clinics in the United States each year, defines ART as any method that involves manipulation of both SPERM and OVA (eggs). Other methods to aid fertility may use interventions such as HORMONE therapies to stimulate OVULATION (the release of ova) in the woman or techniques such as intrauterine artificial insemination (placement of sperm within the UTERUS) to improve sperm viability. ART typically becomes an option to treat INFERTILITY when less invasive approaches fail to result in pregnancy or when health factors compromise fertility in both partners.
Methods of Assisted reproductive technology - ART
Most methods of ART involve uniting sperm and ova outside the body and returning the results to the woman’s body. There are four commonly used methods of Assisted reproductive technology:
- In vitro fertilization (IVF) is the most common method of ART. The technologist mixes sperm and several ova together in a laboratory container. The sperm penetrate and fertilize the ova. After the zygotes form, the fertility specialist transfers two to four zygotes into the woman’s uterus. IVF eliminates issues of sperm motility, sperm antibodies, and blocked FALLOPIAN TUBES. It may be an appropriate choice for male factor infertility, female factor infertility, or combined factor infertility and may use donor eggs, donor sperm, or eggs and sperm collected from the woman and her partner.
- GAMETE intrafallopian transfer (GIFT) mixes ova and sperm in a thin catheter and transfers the mixture directly to the woman’s fallopian tube. Fertilization takes place within the fallopian tube and the ZYGOTE travels to the uterus to implant. GIFT may be the ART method of choice when the woman has healthy fallopian tubes and male factor infertility is the primary issue. GIFT is also an acceptable method of assisted CONCEPTION within cultures and belief systems in which fertilization must take place inside the woman’s body.
- Intracytoplasmic sperm injection (ICSI) is somewhat like IVF though leaves less to chance. The technologist extracts a single sperm from the collected sperm and injects it into an ovum to fertilize the ovum. The fertility specialist then transfers the zygote into the woman’s fallopian tube or uterus. ICSI is often the ART method of choice for male factor infertility, especially when the man’s sperm count is very low.
- Zygote intrafallopian transfer (ZIFT) begins with IVF though the fertility specialist then uses laparoscopy to place two to four zygotes into the woman’s fallopian tube. ZIFT is a common ART choice for male factor infertility and may be appropriate when IVF has not succeeded. Fertility specialists believe the embryos that result from IVF may be more fragile than those that develop within the fallopian tube.
Before any of these methods can occur, the fertility clinic must obtain ova and sperm, either from the woman and man undergoing ART or from donors. Ova retrieval begins with injection of a hormone, human chorionic gonadotropin (hCG). Then, 36 hours later, the fertility specialist aspirates (gently suctions away) the ripened ova using a catheter inserted into the pelvic cavity through the vagina with ULTRASOUND to visualize and guide the process. Sperm retrieval may occur through EJACULATION or the fertility specialist may extract sperm, using needle and syringe, directly from the man’s testicle (EPIDIDYMIS). Sperm extraction does not require hormones.
Success of Assisted reproductive technology
About 45,000 births occur in the United States each year as a result of Assisted reproductive technology, representing about a 25 percent success rate overall for ART. However, many couples undergo multiple ART attempts, and the rate of pregnancy correlates to the woman’s age with a precipitous drop after age 35. Nearly a third of ART conceptions are multiples (twins or higher), a consequence of the practice of implanting multiple embryos to improve the likelihood of a viable pregnancy (pregnancy that carries to full term with delivery of a healthy baby). Some ART methods are more successful than others, depending on the infertility circumstances. As well, the ART may succeed in generating a pregnancy but the pregnancy does not carry to term. The CDC reports annual ART success rates for pregnancies and live births according to ART method and by fertility center. The report is available at the CDC’s Web site (www.cdc.gov/art).
Concerns and Risks of ART
Despite significant advances in understanding and technology, much about fertility remains a mystery. The long-term risk associated with hormone use to stimulate ovulation for egg retrieval in women is probably negligible but remains unknown. Risks for chromosomal and genetic damage also remain unknown. However, since the first successful IVF in 1978, hundreds of thousands of babies born through ART methods have reached adulthood and many now have children of their own with both parent and child healthy. It is important for people considering ART to know as much as possible about their family health histories and to fully understand the possible complications and risks for the methods of ART they are considering, because knowledge in this area changes rapidly.
See also ADOPTION; FAMILY PLANNING.
