Test Tube Babies - IVF & GIFT
from the book How to Have a Baby:
by Dr. Aniruddha Malpani, MD and Dr. Anjali Malpani, MD.
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GIFT stands for gamete intrafallopian transfer. A gamete is a male or female
sex cell - a sperm, or an egg. During GIFT, sperm and eggs are mixed and
injected into one or both fallopian tubes. After the gametes have been
transferred, fertilization can take place in the fallopian tube as it does in
natural, unassisted reproduction. Once fertilized, the embryo travels to the
uterus by natural processes.
As in IVF, a GIFT treatment cycle begins with ovulation enhancement which is
followed by egg harvest, usually by means of laparoscopy. But the similarity to
IVF ends here. In IVF, an embryo is transferred. In GIFT, gametes are
Only patients with at least one normal, healthy fallopian tube are candidates
for GIFT. These include women who have unexplained infertility or mild
endometriosis and couples whose infertility results from male, cervical, or
immunological factors. Some doctors recommend that couples with male factor
infertility proceed with GIFT only if it has been proven that the man's sperm
can fertilize the woman's egg either by in vitro fertilization or by past
The Basic Steps of GIFT
The basic steps of GIFT are ovulation enhancement, egg harvest, insemination,
and gamete transfer. The eggs are usually harvested during laparoscopy. During
this same laparoscopy procedure, which takes about an hour , eggs are mixed with
sperm and the gametes are transferred.
The harvested eggs are examined under the microscope and graded for maturity.
The selected eggs are placed in individual dishes and combined with sperm
(insemination). The sperm are prepared in advance in the same manner as for IVF.
Some doctors prefer to allow the dishes to sit for about 10 minutes before the
transfer, since during this period the sperm adhere to the zona pellucida of
each egg. Many programs load eggs and sperm individually into a catheter and
inject them into one or both of the fallopian tubes.
The sperm egg mixture is loaded into a specially designed catheter . This is
then directed into the fallopian tube(s) through their fimbrial opening while
looking through the laparoscopy. Up to four eggs and sperm may be injected into
one or both tubes. Gametes will be transferred only if the fallopian tubes
appear healthy. If the surgeon determines that the tubes are unhealthy, IVF
should be attempted instead. For this reason, GIFT should be undertaken only at
facilities that have the capability to do IVF.
Specialists generally agree that pregnancy rates are higher for GIFT than for
IVF- in fact, GIFT is about twice as successful as IVF. In part, this may be due
to the type of patient accepted into GIFT programs. It may also be because the
in vivo tubal environment is more "physiologic " for the gametes and
embryo than the in vitro environment.
The advantages of this technique are :
- the fallopian tube acts as the laboratory
- the embryo will reach the uterus at a later stage in its development, as
with normal conception.
- the procedure is considered morally acceptable to some religious groups
which object to IVF, as conception occurs within the human body.
- the endometrium will also be more receptive to the embryo because of the
greater time the embryo takes to reach the uterus.
GIFT & IVF Compared
There are several differences between GIFT and IVF. The most important one is
that GIFT requires at least one healthy fallopian tube, whereas IVF is
appropriate treatment for women with tubal disease or even no fallopian tubes at
all. At present, GIFT requires laparoscopy for transfer, while an IVF treatment
cycle can be completed without laparoscopy. This is one of the reasons many IVF
clinics no longer offer GIFT , even though it offers a higher pregnancy rate -
because they do not have easy access to an operation theatre. Ideally, you
should opt for treatment in a clinic which offers all the procedures, so that
the doctor can select the one which is best for you, depending upon your
In the case of GIFT, fertilization occurs unobserved inside the body. With
IVF, fertilization takes place in a laboratory dish and can be confirmed
visually with a microscope. Visual confirmation of fertilization is especially
important in cases of male factor or unexplained infertility. To obtain visual
confirmation and still have the greater chance of pregnancy afforded by GIFT,
one of the variations of GIFT described later (ZIFT, PROST or TET) may be used,
to give the patient the benefit of combining the advantages of both the
A major disadvantage with conventional GIFT is that a surgical procedure -
laparoscopy - is needed to transfer the eggs and sperm into the fallopian tube.
Recently, a non-surgical method has been described by Dr. Jansen and Anderson
from Sydney IVF, Australia, in which the gametes can be transferred into the
fallopian tubes through the vagina and cervix under ultrasound guidance. This
requires a special set of catheters which allow the doctor to enter the uterine
ends of the fallopian tubes through the cervix. Once the catheters have been
accurately positioned - and ultrasound can help in this - the gametes are
injected into the tubes. Since this does not involve surgery, the benefits to
the patient are obvious - less expense, no hospitalization, no scar and no
anesthesia. However, the technique does require much more technical expertise
and is still being investigated more thoroughly. Also, the pregnancy rates with
the method are less than with conventional laparoscopic GIFT.
The Cost of GIFT
The cost of a GIFT treatment cycle varies from programme to another, falling
within the same basic Rs 30000 to Rs 70000 plus range typical for IVF.
Variations of GIFT
Variations of GIFT include procedures with names like ZIFT, PROST, TET - an
alphabetic potpourri !
ZIFT, zygote intrafallopian transfer, is also called PROST, which stands for
pronuclear stage transfer. When a sperm penetrates an egg, the sperm introduces
its nuclear material into the egg. Approximately 14 hours after penetration, two
distinct pronuclei, one from the sperm and one from the egg, are visible under
the microscope. Pronuclei are taken as indicators that fertilization has
occurred. A zygote is a fertilized egg before cell division begins. For ZIFT,
eggs are removed by transvaginal aspiration and fertilized in a laboratory dish.
The next day, when the fertilized eggs have reached the pronuclear stage, the
embryos are transferred to the fallopian tubes during laparoscopy.
Approximately 24 hours after a fertilized egg reaches the pronuclear stage,
it divides for the first time and becomes a two cell embryo. This cell division
is called cleavage. It is at this stage or later that TET, tubal embryo
transfer, may be attempted. The fertilized and dividing egg (early cleavage
stage embryo) is transferred to the fallopian tube during laparoscopy.
PROST, ZIFT, and TET differ from GIFT in that fertilization takes place in a
laboratory dish instead of the fallopian tube. Moreover, they differ from IVF in
that the fertilized egg is transferred to the fallopian tube instead of to the
uterus. They offer the best of both IVF and GIFT - documentation of
fertilization in vitro; and higher pregnancy rates because of tubal transfer.
However, the cost of ZIFT, PROST, or TET is usually greater than IVF or GIFT .
Success Rates - Making Sense of the Figures
[continued on next page]
by Dr. Aniruddha Malpani, MD and Dr. Anjali Malpani, MD.
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