In Vitro Fertilization
trying to have a child, the probability of getting pregnant is about 20-25% in
a single cycle. That number goes up to 90% within a year. However, for about
10% of couples, infertility is a real issue. These days, outside societal
factors such as trying to achieve academic or career-oriented goals mean that
woman seem to be getting married at older ages. Consequently, this means that
women are also older by the time they start trying to have kids, comparative to
historical statistics. Many of these older couples are highly-educated, but
still have unrealistic expectations when it comes to their fertility. In fact,
the older you are, the harder it may be to not only conceive, but carry the
child to full term. Regardless of the reason for infertility, in vitro
fertilization, or IVF, is the best way to achieve pregnancy. Started in 1978,
IVF has gained significant popularity all over the world. Now approximately one
out of every fifty births in Sweden is attributed to IVF. In addition, one of
every sixty births in Australia and one of every eighty to one hundred births
in the United States are also because of IVF. In 2003, there were more than
48,000 IVF babies born in the U.S. alone.
explain how the process of IVF works. Then, I’ll explain how women are screened
to be eligible for IVF. I will also talk about some benefits and some risks of
IVF, before briefly touching on a couple different treatment options.
itself is highly technical, but can be broken down into a few steps. The first
step is the ovarian stimulation. Gonadotropins, which are natural hormones
produced by the body to manage the reproductive cycle, are injected every day
in a more concentrated manner to create better fertility. This encourages the
maturity of more eggs in a single cycle. Second, is the egg retrieval.
Essentially, a doctor will use an ultra sound to guide a needle into the ovary
and extract the eggs. Once the eggs have been retrieved, the next step in
fertilization. One way fertilization can happen is by culturing several sperm
and the retrieved eggs together in a test tube, similar to how fertilization
would occur naturally in the fallopian tubes. The second way is by a newer
procedure called intracytoplasmic sperm injection. Simply put, one sperm and one
egg are combined in a Petri dish under a microscope. This new way has increased
the rate of pregnancy in couples that suffer from sever male factor infertility
by being able to choose the specific sperm used in fertilization.
Intracytoplasmic sperm injection is now used the majority of all IVF cycles.
The next step is to culture the embryos. In an incubator, the embryos are grown
for either 3 or 5 days. They are then transferred back into the woman’s uterus
to continue to grow normally.
comes to screening for infertility, most couples go through a standard
infertility evaluation. This can include a semen analysis and an assessment of
the female reproductive tract. The ovarian reserve is also frequently looked at
on women. The ovarian reserve is the amount of eggs remaining in the ovary. The
fewer eggs there are left, the less the ovaries will respond to medication.
Consequently, fewer eggs can be retrieved, which leads to fewer embryos and a
lower pregnancy rate. A reduced ovarian reserve is often the reason for
unexplained fertility. Women over the age of 35 tend to have lower results when
it comes to this test. Women over 40 usually have a hard time getting pregnant
even when all their results are normal.
benefit of doing IVF is that it produces the best pregnancy rates per cycle
compared with other fertilization treatments. The pregnancy rate per cycle with
fresh, non-donor eggs is about 34%, while the live birth rate is about 28%.
Even though this is highly effective, most IVF cycles do not end in pregnancy.
Another benefit is for older women or couples who want to have children. Women
who are over 34 have a live birth rate of 40-49%. This percentage drops 2-6%
for every year the woman ages. By age 43, the live birth rate is 5% and over
50% of pregnancies end in miscarriage. Comparatively, older women who undergo
IVF with a younger woman’s donor eggs have seen a lot more success and the rate
of pregnancy seems to not be affected by the age of the carrier. Therefore, it
can be concluded that the reduced live birth rate is directly affected by
lowered function of the ovaries and poorer egg quality, not by the ability of
the uterus to carry a child.
benefit of IVF is the use of cryopreservation. Cryopreservation can be very
cost effective for future IVF cycles, as it skips almost all the steps in the
original process. In addition, any frozen embryos that remain can be donated to
other couples struggling to conceive, or donated for scientific purposes.
also risks associated with IVF. A big risk is multiple gestation. Out of all
pregnancies conceived by IVF treatment in 2003, 31% were twins, and 3% were
triplets or more. This statistic is compared with only 1% of naturally
conceived multiples. Multiple gestation can be a result of several different
factors. The first thing that can contribute to multiple gestation is the
transfer of more than one embryo. This can be in an effort increase chances of
pregnancy in the first cycle to reduce further costs, as some states do not
cover IVF under their insurance policies. Some couples even prefer multiples as
way to get to their ideal family size in less time. Another thing that can lead
to multiple gestation is monozygotic twinning. This simply means that the single
embryo spontaneously splits into two embryos, resulting in identical twins. The
chance of monozygotic twinning is also increased as result of IVF. There are
many risks to women who carry multiple fetuses, including a higher need for bed
rest, higher risks of premature labour, C-sections, post-partum hemorrhaging,
and, although rare, death. Carrying multiples can also lead to higher hospital costs
in the U.S.
risk to the mother can be Ovarian Hyperstimulation Syndrome. It is due to the
gonadotropin stimulation and early pregnancy. This is a short-term affect and
happens in less than 5% of IVF cases. Some symptoms include swelling of the
ovaries, pain in the pelvis, and hemodynamic fluid shifts, often in combination
with ascites. This syndrome almost always goes away after a few weeks, although
in very rare cases death due to thromboembolism has been reported.
news is that no long-term effects on women’s health as a result of IVF have
downfall of IVF is the result that 6.2% of children born due to IVF have had
major birth defects, compared with only 4.4% of naturally conceived children. However,
the correlation is unclear.
One area of
uncertainty when it comes to infertile couples is whether IVF is the best
course of action. There are several other treatment options for couples who
have infertility issues, such as intrauterine insemination and ovulation induction,
either alone or together. These treatment options can be much less costly than
IVF, however, with pregnancy rates between 5 and 15% per cycle, the chance of
pregnancy will be much lower.
IVF is a
practice used world-wide, due to its high rate of pregnancy and its ability to
give options to those who may be dealing with infertility. It is a very
technical process comprised of ovarian stimulation, egg retrieval,
fertilization, embryo culturing, and transferring the embryo back to the
uterus. Couples who want to go through IVF are screened to try to determine
reasons for infertility, using tests such as semen analysis and female
reproductive tract assessment. There are many benefits to using IVF, such as
its high rates of pregnancy, compared to other treatments, and being able to cryopreserve
embryos. However, there are still risks associated to using IVF, such as high risk
of multiple gestation and low risk to the mother’s health. There are other
treatment methods that can be used to conceive, however, none with pregnancy
rates as high as IVF.
like to note that this article is from 2007, so some statistics I have used may
be out of date. In addition, there are even more advanced methods of IVF that
fertility clinics have started using in recent years.
Miranda reporting for ABC News.