5. Terminology of Assisted Reproduction Technology

IUI: Intrauterine insemination. Sperm is specially prepared and inserted into the cavity of the uterus after multiple ovulation induction. Useful for treating unexplained infertility or mild disruptions in the sperm quality.

GIFT: Gamete intrafallopian transfer. Insertion of unfertilized eggs and prepared sperm into the fallopian tubes with laparoscopy. Better than IUI in all circumstances, with about twice the pregnancy rate (often well over 35% per cycle of treatment). Also useful in more moderate decreases of the sperm quality, endometriosis, peritubal adhesions (some cases), sperm antibodies and abnormalities of the cervix.

IVF: In vitro fertilization. The eggs are obtained from the ovaries and are then fertilized in the laboratory. Conventionally the embryos are transferred to the uterus, but if the fallopian tubes are normal they can be transferred to the tubes (i.e. ZIFT). From our last statistics of our Center (2002) the chance of pregnancy is over 50% per cycle with embryotransfer up to the age of 40. After this age the pregnancy rate is reduced (as happens with all methods of assisted conception).

ET: Embryo-transfer. Unless otherwise stated, refers to transvaginal transfer of embryos through the cervix into the uterus.

Cryo-ET (EMBRYO CRYOPRESERVATION, THAW AND EMBRYOTRANSFER): Transfer of embryos that have been derived in a previous IVF or GIFT cycle and stored, frozen in liquid nitrogen (-196°C).

ZIFT: Zygote intrafallopian transfer. Introduction of fertilized eggs ("zygotes") into the fallopian tube, with laparoscopy. Comparable pregnancy rate to GIFT when the sperm quality is otherwise too poor for GIFT.

ICSI: Intracytoplasmic sperm injection. A type of IVF in which single sperm cells are injected into the soft center of the egg using special micromanipulation equipment. A treatment of choice for extremely poor sperm quality. It can be combined with male testicular biopsy in cases of complete absence of sperm when there is an obstruction or, in cases with maturation arrest within the testicles. Pregnancy rates are comparable as for IVF.

MESA: Microsurgical epididymal sperm aspiration. Obtaining spermatozoa from the epidydimis (which joins the testis to the vas) can overcome azoospermia from tubal obstruction. The spermatozoa can then be used for microinjection- ICSI.

BLASTOCYSTS: Human in vitro fertilization and embryo transfer is relatively inefficient in that there is only a 25% chance (depending on the woman's age and other fertility factors) that an individual fertilized egg (embryo) will implant in the uterus and establish a pregnancy. For this reason, it has been standard to transfer more than one embryo (usually 3 or 4) in each IVF cycle an effort to improve the overall chance of pregnancy. Although this method successfully increase the pregnancy rates, it is associated with a high order multiple pregnancies such as triplets or more. Multiple pregnancies have a higher rate of complications, particularly premature delivery with consequences in children. With the development of improved culture media, a considerable number of developing embryos will survive in the laboratory for up to six days after the egg recovery. By the 5th or 6th day, some embryos should reach the blastocyst stage, recognized by the degree of cell division and the formation of a distinct internal structure.

It has been traditional to transfer embryos to the uterus 2 or 3 days after egg recovery. Many IVF failures are probably due to failure of the embryos to develop normally after transfer. By transferring embryos at the blastocyst stage, we have a greater ability to select normally developing embryos with a greater potential for implantation and pregnancy. Therefore, a good pregnancy rate can be achieved by transferring fewer (one or two) blastocysts without the risk of high order multiple pregnancies.

Only about (40-50%)of fertilized eggs will reach the blastocyst stage in culture. There is a risk (estimated at about 10%) that none of the embryos will reach the blastocyst stage during the culture period (for example the development may stop on the third or fourth day in culture). Although embryo transfer is cancelled in these cases, the information learned may be helpful in planning future treatment.

We are proud to be the first IVF unit in Greece to provide blastocyst transfer in the year 1997 and deliver the first such babies in Greece in June 1998. Since then we have a huge number of women pregnant with blastocyst transfer and this number is growing continuously.

ASSISTED HATCHING: Assisted hatching is a technique where the zona or coating of an embryo is opened in the hope that this will assist the hatching of the embryo and improve the implantation and pregnancy rates. The procedure is generally done two-three days after egg collection or on the day that frozen embryos are thawed, the embryo transfer being performed the same or the following day. Assisted hatching carries no risk to a woman but there is a small risk of losing an embryo as result of damage during manipulation. Recently the use of Laser in our Center to perform assisted hatching has reduced the % of cell damage. The cells of the embryo itself are not altered and there is no reason to expect any abnormalities as a result of this technique. Assisted hatching has been suggested for couples who have had a number of unsuccessful embryo transfers and for those in which pregnancy rates are lower because of age.