IVF – in vitro fertilization
IVF is a technique involving the fertilisation of eggs by sperm outside the body. The term literally means 'fertilization in glass' - hence the commonly used description 'test-tube baby' technique.
IVF treatment is made up of a number of procedures usually referred to as a 'treatment cycle'. An outline of what is involved in a typical IVF treatment is described below.
Down regulation - Firstly, the woman is prescribed a drug taken in the form of a nasal spray or an injection which suppresses the release of the hormones responsible for the production of an egg. This is necessary in order to establish a 'baseline' from which to start ovarian stimulation and to prevent spontaneous ovulation before egg collection can take place.
Ovarian stimulation - Once a base line has been established, the woman commences ovarian stimulation which takes the form of a daily intra-muscular injection. Stimulating the ovaries in this way should produce several eggs to ensure that there are enough suitable eggs for fertilization.
Monitoring - Regular monitoring of the effects of the drugs on the ovaries is undertaken through ultrasound scans and blood tests.
Final injection - When the ultrasound scan and blood tests indicate that there are a sufficient number of mature follicles (the sacs in which the eggs grow), a final injection is administered to ensure the ripening of the eggs in preparation for the egg collection.
Egg collection - Eggs are collected from the ovaries through the vagina using a fine needle under ultrasound guidance to aspirate the eggs from the follicles. This is performed as a day-case, typically under sedation.
Sperm production & preparation - On the day of the egg collection, the male partner is required to produce a semen sample at the centre. The sample is then prepared in the laboratory to extract the most motile sperm.
Embryology - When all the eggs have been collected, they are put in a dish with the prepared sperm and incubated in the laboratory. Approximately sixteen hours later, the embryologist will check to see whether fertilization has occurred.
Embryo transfer - If fertilisation has occurred, usually two of the embryos are transferred directly into the uterus two days after the egg collection. The embryos are transfer through the vagina and cervix using a fine catheter. This procedure is usually pain free.
Pregnancy test - A pregnancy test should be carried out fourteen days after the embryo transfer. If the result is positive, an ultrasound scan is recommended two or three weeks later to check the embryo is alive and situated in the uterus.
GIFT (Gamete Intra-Fallopian Transfer)
GIFT is an early, and very simple ART (Assisted Reproductive Technology) technique. The success rate with GIFT is even somewhat higher than with standard IVF (in vitro fertilization), but GIFT can be performed only if the patient has normal fallopian tubes and adequate sperm. For cases with abnormal fallopian tubes, IVF is mandated.
GIFT stands for "Gamete Intra-Fallopian Transfer." Gametes, i.e., the female's eggs and the male's sperm, are washed and placed via a catheter directly into the woman's fallopian tubes. This usually involves a minor surgical procedure which allows you to go home the same day with a minor degree of pain that lasts for just a few days. With GIFT, fertilization occurs inside the woman's body (not outside), and mimics the way a normally fertilized egg would begin its journey to the uterus for implantation. Understanding this older and more "natural" ART treatment is helpful for understanding the newer, more complex treatments.
How Does GIFT Work?
In a fertile couple, pregnancy begins with the release of an ovum (egg) from the woman's ovaries. The egg enters the fallopian tube where it meets with sperm that have traveled there, following intercourse, from the vagina. The sperm normally fertilize the egg in the fallopian tube. The fertilized egg, now called an embryo, begins to divide and in four days, contains many cells. At this time, the embryo moves from the fallopian tube to the uterine cavity where it "floats" for another two days. The embryo then implants in the uterine wall, and becomes a pregnancy.
The GIFT technique follows nature by allowing the eggs to fertilize and develop in the natural environment of the fallopian tube, and then to make their way to the uterus for implantation according to a normal timetable. In contrast, in vitro fertilization (IVF) places fertilized eggs directly into the uterus. One of GIFT's major advantages over IVF is that the technique relies to a far greater degree on the body's natural processes and timetable to produce pregnancy, and is acceptable to those religious groups which avoid the more embryo invasive technologies. In technical IVF terms, we would say that it is the best of all methods of "co-culture".
The fluid containing the eggs is placed in a laboratory dish and observed under a microscope. The egg is located and its stage of maturity noted. It is then carefully cultured in a special nutrient. Sperm and eggs are sequentially loaded into the catheter, which is then introduced into the patient's fallopian tubes through a tiny incision in her abdomen.