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 takeplace 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 cyclebegins with ovulation enhancement which is followed by egg harvest, usuallyby means of laparoscopy. But the similarity to IVF ends here. In IVF, anembryo is transferred. In GIFT, gametes are transferred.
Only patients who have at least onenormal, healthy fallopian tube are candidates for GIFT. Such patients includewomen who have unexplained infertility or mild endometriosis and coupleswhose infertility results from male, cervical, or immunological factors.Some doctors recommend that couples with male factor infertility proceedwith GIFT only if it has been proven that the man's sperm can fertilizethe woman's egg either by in vitro fertilization or by past pregnancies.
The Basic Steps of GIFT
The basic steps of GIFT are ovulationenhancement, egg harvest, insemination, and gamete transfer. The eggs areusually harvested during laparoscopy. During this same laparoscopy procedure,which takes about an hour, eggs are mixed with sperm and the gametes aretransferred.
The harvested eggs are examined underthe microscope and graded for maturity. The selected eggs are placed inindividual dishes and combined with sperm (insemination). The sperm areprepared in advance in the same manner as for IVF. Some doctors preferto wait for about 10 minutes before the transfer, since during this periodthe sperm adhere to the zona pellucida of each egg. Many programmes loadeggs and sperm individually into a catheter and inject them into one orboth of the fallopian tubes.
The sperm - egg mixture is loadedinto a specially designed catheter . This is then directed into the fallopiantube(s) through their fimbrial opening while looking through the laparoscopy.Up to four eggs and sperm may be injected into one or both tubes. Gameteswill be transferred only if the fallopian tubes appear healthy. If thesurgeon determines that the tubes are unhealthy, IVF should be attemptedinstead. For this reason, GIFT should be undertaken only at facilitiesthat have the capability to perform IVF also.
Specialists generally agree thatpregnancy rates are higher for GIFT than for IVF - in fact, GIFT is abouttwice as successful as IVF. In part, this may be due to the type of patientaccepted into GIFT programmes. It may also be because the in vivo tubalenvironment is more "physiologic " for the gametes and embryo than thein vitro environment.