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In-Vitro
Fertilization (hereinafter referred to as "IVF") is a
procedure in which a woman's ova (eggs) are fertilized outside of
her body. One IVF treatment cycle takes several weeks to complete.
IVF can be a successful treatment for blocked or absent fallopian
tubes, sperm abnormalities, endometriosis, problems with ovulation,
egg donation, gestational surrogacy, or unexplained infertility.
During
a normal menstrual cycle, usually only one egg is produced by a
woman each month. In an IVF cycle, the chances of pregnancy are
increased by stimulating the woman's ovaries with medication so
that many eggs, instead of only one, will develop. Once the eggs
have matured, they are removed from the woman's ovaries and fertilized
by sperm in the IVF laboratory. After the egg(s) has/have been fertilized
by sperm, some or all of the resultant embryos are placed into the
woman's uterus using ultrasound guidance so that they may implant
and develop into a viable pregnancy. Embryos that are not transferred
into the woman's uterus may be cryopreserved (frozen) for use in
a future treatment cycle, thereby avoiding the need to repeatedly
retrieve the woman's eggs. It may be recommended that any slower
growing embryos be allowed to develop further, and then freeze them
if they mature further.
While
most IVF pregnancies result in single births, the risks of IVF include
multiple gestation (twins, triplets, etc.), bleeding, infection
and ovarian hyperstimulation syndrome.
Multiple
pregnancy is associated with increased risks of prematurity and
death, or long term disability, of some or all of the babies.
In
about 1-3% of IVF patients, ovarian hyperstimulation may occur.
When this happens, the woman's ovaries become enlarged and fluid
may accumulate in her abdomen. In this situation, it may be necessary
to drain the excess fluid from the abdomen on one or more occasions.
If
a viable pregnancy is established, complications with this pregnancy
may occur, as they may with any other pregnancy, including miscarriage,
ectopic pregnancy and congenital abnormalities in the fetus.
During
each IVF treatment cycle, transvaginal ultrasounds are performed
to monitor the growth of the follicles (egg sacs) in the woman's
ovaries. Blood testing is undertaken to monitor the woman's hormone
levels. The number of developing follicles is correlated with the
blood test results. If necessary, the amount of medication being
administered to stimulate the ovaries to develop eggs may be adjusted
as the cycle progresses. When the woman's eggs have neared maturity,
she is given an injection of HCG (Human Chorionic Gonadotrophin)
to complete the maturation of the eggs. The HCG injection is given
approximately 35-37 hours prior to egg retrieval.
On
the day of egg retrieval, a sperm sample is obtained from the male
partner (or donor) and the sperm are prepared to fertilize the eggs.
Prior
to the procedure to retrieve the eggs, an intravenous (IV) is started.
During the procedure local anesthetic may be used to freeze around
the cervix and IV medications are usually used for sedation and
pain relief. Nitrous oxide ('laughing gas') is also available if
required. Egg retrieval involves the physician passing a needle
through the posterior (back) wall of the vagina, guided by ultrasound,
into the ovaries. The fluid from each follicle is aspirated into
a test tube. The woman's eggs are microscopic (ie. not visible to
the naked eye) and are floating in the fluid. The sample is forwarded
to the Embryologist who will locate the eggs in the fluid using
a microscope. For various technical reasons, an egg is not always
obtained from each follicle. The eggs that are retrieved are then
combined with sperm, either by mixing them together, or by ICSI
(intracytoplasmic sperm injection) or both, depending on the specific
situation.
Some
or all of the resulting embryos are transferred into the uterus
after they have been allowed to grow in the laboratory for 3-5 days.
There is a rare possibility that despite the aspiration of fluid
from each of the follicles that: no eggs will be retrieved; some
or all of the retrieved eggs will not fertilize; and/or few or none
of the fertilized eggs will develop into a viable embryo.
When
they are ready to be transferred, the embryos are placed into a
thin tube known as a catheter. The catheter is inserted into the
woman's uterus and the embryos are deposited into the uterus using
ultrasound guidance. For this procedure patients are required to
have a full bladder. Following embryo transfer, the woman is usually
prescribed Progesterone and/or other medication(s) to help the embryo(s)
implant in the uterus.
After
the embryo transfer, it is recommended that the woman avoid: stressful
situations as much as possible; avoid anything that will significantly
raise your body temperature (eg. Saunas, very hot baths, high impact
exercise); douching; and heavy lifting. Otherwise, she may resume
normal activities on the day following the embryo transfer.
Two
weeks after embryo transfer, the woman returns to the CReATe Program's
clinic to have a blood test obtained to see whether she is pregnant.
If the pregnancy test is positive, the woman must continue to take
Progesterone and/or other medication(s), as directed, until advised
otherwise.
An
ultrasound is performed about 6.5 weeks into the pregnancy (about
4.5 weeks after the transfer) to confirm that one or more fetal
heart(s) are present and that the fetus is/are growing appropriately.
The physicians at the CReATe Program prefer to follow each pregnant
patient during the first 3-4 months, to make sure the pregnancy
gets off to a healthy start. During this time period, we can refer
you to an obstetrician that we recommend, or to a obstetrician,
family physician or midwife of your choice, depending on your preference.
In some cases, if the pregnancy is felt to be high risk (such as
a twin pregnancy), we will recommend an obstetrician who specializes
in high risk pregnancies.
If
you have any further questions about IVF, or if you require clarification
of any of the issues raised above, please speak with your physician.
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