Fertilization
Patient egg, sperm and embryo identification
Sydney IVF Newcastle is accredited by the National Association of Testing Authorities (NATA) the Reproductive Technology Accreditation Committee of the Fertility Society of Australia (RTAC) and has obtained ISO 9001-2000 accreditation for quality management. As part of this accreditation the laboratory is required to have to independent pieces of identifying information on all biological specimens which includes all containers for eggs, sperm and embryos. This methodology is strictly followed to avoid any potential confusion.
Sperm Supply
Sperm are a essential part of IVF. A semen sample needs to be provided on the day of egg collection. The scientist at Sydney IVF Newcastle will inform you of the best time for the sample to be available. It is common for men to feel some anxiety about producing a semen sample on demand. If you think this will be difficult for you please notify the clinic in advance. Occasionally, there are no sperm in the semen and they need to be extracted directly from the testis or epididymis (tubules just next to the testis). This is generally performed in advance of the egg collection procedure and the sperm are frozen. It might be necessary to repeat this on the day of egg collection if the sperm do not survive freezing.
Fertilization Methods
The most common method of fertilization is to place concentrated sperm with the eggs in a small amount of culture fluid. This generally results in about 50% to 75% of eggs fertilizing and becoming embryos. The alternative is intracytoplsmic sperm injection (ICSI).
Intracytoplasmic sperm injection (ICSI)
ICSI is a treatment for severe male factor infertility. ICSI can be used when sperm count and/or the motility (swimming) of the sperm is below normal ranges. The experience of IVF clinics in Australia and overseas indicate that ICSI can be used when there are very few sperm in number, as long as there is evidence that some of the sperm are alive. More recently sperm from the epididymis or the testes have been shown to achieve fertilization and pregnancies.
What happens during ICSI
The ICSI process is an extension of the IVF Programme from the couples' point of view. The woman is required to have the standard regimen of drugs to stimulate her ovaries so that a number of eggs can be recovered. Once the eggs are collected the partner is asked to produce a sperm sample by masturbation (or if no sperm are present, by an operation to collect them from the epididymis or testes). The biologist then selects one sperm from the washed sample and transfers that single sperm to the inside of an egg using a very long thin pipette (needle). One sperm per egg is used. The process is very time consuming and there can be potential damage to the egg(s) due to excessive manipulation. It is thought that up to 20% of eggs may rupture or burst when the sperm is injected, and a number of eggs may not correctly absorb the chromosomes from the sperm. The technique is more complicated than routine IVF and consequently is more susceptible to environmental stress.
 |
The results from ICSI
The incidence of abnormalities in pregnancies as a result of ICSI is slightly higher than with IVF. This is not believed to be due to the procedure itself but because of underlying genetic abnormalities in the male partner. If you have a low sperm count then this may be due to a genetic abnormality which could then increase the risks for the pregnancy. Your doctor will discuss this with you and may suggest certain genetic tests before proceeding with treatment. Long term follow up studies of ICSI conceived children show they perform just as well at school as their IVF and naturally conceived peers.
Fertilization rates are similar to those obtained using routine IVF with normal sperm parameters. Some couples still fail to achieve fertilization. If you choose to use the process, you should be aware of these risks and appreciate that technical and other problems that can occur throughout the cycle.
Couples considering ICSI should take the opportunity to discuss the technique in greater detail with a biologist. Sometimes you may be asked to produce several sperm samples in order to verify the reproducibility of recovering some motile sperm.
Embryo Culture
This involves growing the embryos in a fluid which is designed to mimic the composition of the fallopian tube. It is a complex salt solution, which also contains amino acids, glucose and other components necessary for very early embryo development. Usually embryos are cultured for 5 days to what is known as Blastocysts. Blastocyst culture has now been proven to be of benefit in selecting the best available embryos and thus maximising the prospects of pregnancy
Blastocyst Culture
 |
 |
 |
 |
 |
 |
| Development of embryos from day 2 to day 6 of in vitro culture | ||
Since the invention of in-vitro fertilisation, scientists have attempted to fertilize and grow embryos to their optimal state before placing them back into the uterus. Accepted techniques have change over time. Until recently the usual practice was to culture embryos in a complex solution of different chemicals and substances for approximately 48-72 hours before transferring them back to the uterus. From the beginnings of IVF. scientists have attempted to prolong the culture of embryos in the laboratory in an effort to maximize the prospect of pregnancy. Up until recently this has been notoriously unsuccessful. Developments over the last 5 years, however, have led to an improvement in culture media, the addition of certain amino acids, and a reduction in the amount of glucose. This has improved the capability of IVF culture medium to sustain embryos in the laboratory for a longer period of time - for 5-6 days. Embryos at this point are known as blastocysts as they develop a fluid collection surrounded by large numbers of cells.
Sydney IVF has now conclusively demonstrated the superiority of culturing of embryos to the blastocyst stage and producing pregnancy rates through IVF equal to the best in the world.
Benefits & Advantages
The major benefit of blastocyst culture is the ability to reduce the number of embryos available for transfer by excluding the poorer embryos. Some embryos of lesser quality are unable to continue growing beyond for more than 3 to 4 days. We are then left with the ‘best quality’ embryos with the highest probability of pregnancy. However there is no guarantee of pregnacy and the quality of embryos cultured 5 to 6 days can vary widely.
Side Effects & Complications
There are a number of potential disadvantages to blastocyst culture. Some peoples’ embryos may not develop beyond the first few days of life and may not make it to the blastocyst stage. In this situation no embryo transfer takes place, despite having a large number of eggs produced from treatment. However if the embryos had been transferred earlier it is unlikely pregnancy would have occurred as it likely development would also have stalled inside the body. Hence we find out earlier rather than later that the cycle has been unsuccessful. Although this can be very devastating in some ways it can give us more information about what is going on.
There appears to be a substantial increase in the risk multiple pregnancy (twins and triplets) when more than one good quality blastocyst is transferred back to the uterus. In some of the initial studies, twin rates of 70% and triplet rates of 40% were produced in selected groups of patients when 3 blastocysts were transferred. The impact on multiple pregnancy rates, however, is much less certain when this type of treatment is applied to everyone undertaking IVF. There is evidence that blastocyst culture increases the risk of identical twin pregnancy (twins from a single embryo). At Sydney IVF Newcastle we recommend that all patients under 40 have only a single embryo transferred back to the uterus.
It would be fair to say that the risks of prolonged culture and blastocyst transfer have not been firmly established. There is no long-term information or studies on the outcome of pregnancies from this method, and there is no knowledge of the potential risk of congenital abnormalities. Based on general principles, however, it is unlikely that there will be an increased abnormality rate for blastocyst culture, given that no known aspect of IVF. treatment to this point has been demonstrated to adversely affect congenital abnormality rates.
Freezing and storage of additional embryos
Should there be embryos additional to those transferred back to the uterus, it may be possible to freeze and store these for treatment at a later date. This may be for another attempt if your fresh cycle was unsuccessful. Or it may many years in the future for a baby brother or sister if your fresh cycle was successful. Freezing and storage of embryos is a highly technical process. It is not possible to be certain about the ability of any embryo to survive freezing. Should you have extra embryos, the scientific staff at the Fertility Centre will give an opinion on the potential benefit that freezing might provide.
In 2007 Sydney IVF Newcastle changed its freezing technique so that now all our blastocysts are vitrified instead of under going “slow-freeze”. Vitrification involves “snap-freezing” the embryos in a glass like state. It is done fairly quickly and requires a high degree of technical skill. The benefit of vitrification is that embryo survival is improved and therefore the chance of pregnancy is much better. Pregnancy rates per attempt are up to 10% higher with this technique and more embryos survive. Around 90% of embryos survive thawing with this technique.
Please remember that not everyone has extra embryos available for freezing. Frozen embryos are a bonus but not all couples have additional extra blastocysts available.
.