becomes an option to treat INFERTILITYwhen less
invasive approaches fail to result in pregnancy or
when health factors compromise fertility in both
partners.
Methods of ARTMost 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 ART:
- In vitro fertilization (IVF) is the most common
method of ART. The technologist mixes sperm
and several ova together in a laboratory con-
tainer. The sperm penetrate and fertilize the
ova. After the zygotes form, the fertility special-
ist transfers two to four zygotes into the
woman’s uterus. IVF eliminates issues of sperm
motility, sperm antibodies, and blocked FALLO-
PIAN 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.
•GAMETEintrafallopian 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 ZYGOTEtravels 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 CONCEPTIONwithin 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 infer-
tility, 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 com-
mon ART choice for male factor infertility and
may be appropriate when IVF has not suc-
ceeded. 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 fer-
tility 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 ULTRASOUNDto visualize
and guide the process. Sperm retrieval may occur
through EJACULATIONor the fertility specialist may
extract sperm, using needle and syringe, directly
from the man’s testicle (EPIDIDYMIS). Sperm extrac-
tion does not require hormones.Success of ART
About 45,000 births occur in the United States
each year as a result of ART, 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 like-
lihood of a viable pregnancy (pregnancy that car-
ries to full term with delivery of a healthy baby).
Some ART methods are more successful than oth-
ers, depending on the infertility circumstances. As
well, the ART may succeed in generating a preg-
nancy 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 avail-
able 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 mys-
tery. The long-term risk associated with hormone
use to stimulate ovulation for egg retrieval in246 The Reproductive System