by Laurie B. Rosenblum, M.P.H.
Perhaps you've followed the news about the septuplets and the octuplets born to
U.S. women in 1997 and 1998. These extraordinary births were the result of
medications taken for infertility. But these two families are not alone.
Infertility affects an estimated five to six million American couples. About 85%
to 90% of them are treated with conventional methods, such as medications to
induce ovulation or surgical repair of reproductive organs. For the remaining
couples, high-tech methods provide further options for having their own
biological child.
Mark and Julie, both age 40, have been trying to get pregnant since their
wedding day two years ago. After six months they both went to fertility
specialists. They found out that Julie has some pelvic scarring and Mark has a
very low sperm count. They tried a few of the low-tech treatment methods with no
success. Since they really want to have their own biological child and not risk
having a multiple pregnancy, they've now decided to try a combination of the
latest techniques available: intracytoplasmic sperm injection and in vitro
fertilization with blastocyst transfer.
High-tech treatments for infertility
The term "assisted reproductive technology" (ART) covers all types of
treatment to induce pregnancy. Artificial insemination and in vitro
fertilization (IVF) were the first two methods of ART, and have been used to
treat infertility since the 1960s and 1970s, respectively.
Various types of ART have been further developed and refined since then and
include:
- Artificial insemination – Sperm are injected into the woman's
uterus or cervix.
- In vitro fertilization (IVF) – Eggs are removed from the ovaries
and fertilized with sperm in a laboratory. Two to four fertilized eggs
(embryos) are then placed in the uterus through the cervix. This is often used
when the fallopian tubes are blocked.
- Gamete intrafallopian transfer (GIFT) – Eggs are removed from the
ovaries and are placed in the fallopian tubes along with the sperm, where
fertilization occurs. This procedure is utilized when at least one fallopian
tube is normal.
Zygote intrafallopian transfer (ZIFT) – Eggs are removed from the
ovaries, fertilized in a laboratory, and placed in the fallopian tubes. They
then travel on their own to the uterus.
- Embryo cryopreservation – Embryos are frozen for use at a later
time.
- Egg or embryo donation – An egg or embryo is provided from a donor
woman to a woman who is not able to produce her own.
- Gestational care – (also called gestational surrogacy) - One woman
carries another woman's embryo through pregnancy until birth, and then
relinquishes the newborn to its genetic parents.
IVF is now used in the vast majority of ART cases, although originally it was
used primarily in women who had problems with their fallopian tubes. As the
success rate has increased over the past several years, IVF is now also used in
cases of endometriosis, immune insufficiency, male infertility, and unexplained
infertility.
The latest innovations in female infertility treatment
Prior to undergoing artificial insemination, IVF, GIFT, and ZIFT, women often
take medication to increase the number of eggs that will mature and be released.
This process is called "ovulation induction" or "superovulation."
In order to maximize the chance of having a child via IVF, more than one
fertilized egg is transferred to the uterus at a time. However, this increases
the risk of giving birth to more than one child. All multiple births are
difficult because parents have to raise more than one child at once. More
importantly, the risk of premature birth and postnatal complications increases
with the number of fetuses carried.
Blastocyst transfer helps reduce the problems caused by multiple births
by decreasing the number of embryos (from an average of four to two) that must
be transferred in order to maintain the same success rate achieved by regular
IVF.
There is another benefit as well. Normally in IVF, embryos are placed in the
uterus two to three days after fertilization in the laboratory. Blastocyst
transfer enables the embryos to be transferred on the fifth or sixth day. The
extra days make it easier to identify abnormally developing embryos and avoid
transferring them. The additional days also give the embryos time to become
stronger, which provides greater opportunity for implantation and eventual
birth. Although these two stronger embryos may produce twins, there is no risk
of giving birth to any more than two babies. This minimizes the ensuing problems
posed by multiple births in excess of twins.
There are several procedures in development that hold promise for treating
female infertility.
- In vitro maturation of eggs involves obtaining immature eggs and
maturing them in a laboratory. This can help to decrease multiple births,
because the women don't have to take ovulation-inducing medications.
- Cryopreservation, the process of freezing unfertilized eggs for
later use, is currently used mainly by women prior to receiving chemotherapy
or radiation. But it may eventually be refined enough to be used on a
widespread basis. Sperm can also be frozen and scientists are researching ways
to freeze ovarian tissue.
- Oocyte nuclear transfer and cytoplasmic transfer involve combining
part of a woman's own egg with part of a donor egg, rather than using just a
donor egg. Some women feel that having at least some of their own genetic
material as part of the embryo takes the "edge" off the stress of these
high-tech procedures.
The latest in treatment for male infertility
A major advance in the treatment of male infertility occurred just a few
years ago.
Intracytoplasmic sperm injection (ICSI) is a procedure used to inject a
single sperm directly into an egg removed from a woman's ovaries. The sperm is
collected from the male through masturbation or surgical removal from the
testicle. After the egg is fertilized in the laboratory, it is placed in the
uterus. This procedure is used in men who have a very low number of sperm and
whose sperm are unable to move successfully through the woman's reproductive
tract and penetrate an egg.
Another potential breakthrough in treating male infertility is round spermatid
nucleus injection (ROSNI). It is designed to help men who do not produce any
sperm. Immature cells (round spermatids) are taken from the testicles. The
nucleus containing the genetic material is removed and injected into eggs that
have been removed from the woman. This process has not yet produced a live
birth, but researchers believe that it ultimately will.
Hope for the future
If you are having difficulty conceiving a child, take heart. A great deal of progress is under way to develop infertility treatments and increase the available options. \"There is great promise that success rates in infertility treatment will continue to increase, and the risks will decrease,\" says Vito Cardone, MD, medical director of the Fertility Center of New England, in Reading, Massachusetts. \"In the future we will be able to maintain a high success rate with simpler treatments that involve less use of medications and are closer to what happens naturally.\"