The Tubal Embryo Transfer (TET) procedure involves the transfer of embryos that are more advanced in development than those in ZIFT i.e. cleaved embryos. The aim is to achieve fertilization in-vitro (in the laboratory) and then replace the cleaved embryos in the Fallopian tube, the normal site for fertilization. It is suitable only for women who have at least one healthy Fallopian tube. TET is carried out as a day-case procedure under a general anesthetic, using laparoscopy(see picture). You may experience some abdominal discomfort and pain for a few days after the procedure, but painkillers can relieve this. The main groups of patients selected for TET procedure are women who are keen to have gamete intra-Fallopian transfer (GIFT) but where there is doubt about the chance of fertilization, and women who encountered difficulties in previous embryo transfers through the cervix. The success rate for TET is in the region of 25-40% per embryo transfer, but varies depending on many factors such as the woman's age and the number of embryos transferred, etc.
The ZIFT procedure involves the transfer of embryos (zygotes) into the Fallopian tube 24 hours after fertilization. The aim is to achieve fertilization in-vitro (in the laboratory) and then replace the early embryos in the Fallopian tube, the normal site for fertilization. ZIFT offers the best of both IVF and GIFT procedures. It is suitable only for women who have at least one healthy Fallopian tube. ZIFT is carried out as a day-case procedure under a general anesthetic, using laparoscopy. You may experience some abdominal discomfort and pain for a few days after the procedure, but painkillers can relieve this. The main groups of patients selected for ZIFT procedure are women who are keen to have gamete intra-Fallopian transfer (GIFT) but where there is doubt about the chance of fertilization, and women who encountered difficulties in previous embryo transfers through the cervix. If the quality of the embryo's in a preceding IVF cycle was poor, some fertility specialists will advise the patient to have ZIFT rather than IVF.
Gamete Intra-Fallopian Transfer (GIFT) is a procedure in which the eggs are mixed with sperm and the mixture is then injected into the Fallopian tube. It is suitable for women who have at least one healthy Fallopian tube. The aim of GIFT is to allow fertilization to occur in the right place and implantation at the right time. There are selected groups of patients to whom gamete intra-Fallopian transfer (GIFT) is recommended:
a)Couples with unexplained infertility.
b)Women with minimal endometriosis.
c)Men with infertility problem (not severe).
d)Couples who have had failed donor insemination.
e)Where transcervical embryo transfer is impossible and the patient has one healthy tube.
The procedure is carried out as a day case surgery under a general anaesthetic, and involves making three small cuts in the abdomen. Fertility drugs are used to stimulate the ovaries, monitoring is also carried out as with IVF treatment. Eggs may be collected either by a vaginal ultrasound scan or laparoscopically using a fine needle and gentle suction.Once the eggs are collected, they are examined under the microscope for quality. The best eggs are then mixed with washed and prepared sperm in a small volume of culture medium. The end of the fallopian tube is grasped gently and a guided fine canula is passed through the fimbrial end of the tube(see picture). The mixture of the eggs and sperm is then deposited into the Fallopian tube. In most cases, three or four eggs are usually transferred per cycle. Any spare eggs that are collected may be fertilized in-vitro and the resulting embryos are frozen (if they are of good quality to freeze) for later embryo replacement. After the GIFT procedure, the patient is usually given hormonal supplements, in the form of tablets, pessaries, gel or injection to help the implantation of embryos.The success rate after GIFT is similar to that of in-vitro fertilization (IVF) treatment. Some specialists claim a higher success rate with GIFT compared to IVF.
More recently, attempts have been made to simplify the procedure by collecting the eggs by vaginal ultrasound and injecting the egg and sperm mixture into the tube via the cervix using a special catheter. The procedure is usually performed under ultrasound guidance. The reported pregnancy rates with this method are less than that with conventional laparoscopy GIFT.
Last week, we did a big Tubal Transfer Procedures Workshop at the Prince Aly Khan Hospital IVF Center (www.testtubebabyclinic.com) where we performed the above procedures on 9 patients. We have made a teaching DVD of the same to teach post-graduates which will be released at the World Congress on Fallopian Tubes to be held at Kolkata from 18-21 October 2007. You can access the meeting homepage on www.sisab.net/tubes2007
