Some of the factors that determine the success of IVF

Emobileclinic Trending Topic: IVF and its outcomes

One issue that dominates the mind of prospective Assisted Reproductive Technology patient is the outcome of the procedure. This is crucial and important for such patients to ruminates about, because, all over the world, ART is a capital intensive procedure, it involves lots of money to perfect all the stages involves in the entire process. The outcome of any procedure either positive or negative is not an easy postulation because there are a number of factors that determine the outcome of the procedure. However, the patient should have it at mind that even naturally conceived pregnancy has its many challenges not to talk of technological aided procedure. 

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Fctors affecting IVF outcome

There is no doubt that IVF helps to diagnose problems of fertilization and embryo development that could not be assessed by any other method. It is both a diagnostic and therapeutic procedure. The complexity of human reproduction means that many factors may play a role in the success or failure of IVF. Some of these factors include Egg and embryo quality, receptivity of the uterus, embryo Transfer, sperm quality etc

EGG/EMBRYO QUALITY 

Age and Ovarian Reserve

Maturation (ripening) is the final step in biological development that a system or organism must undergo in order to prepare for optimal function. Ultimately the functional efficiency of the system and/or organism will be predicated upon its state of readiness to undergo such maturational fine tuning. A poorly developed system/organism can thus never attain optimal functionality. The same concept applies with regard to the development and maturation of a woman’s eggs. Since it is predominantly the egg rather than the sperm that determines the potential of an embryo (the fertilized egg) to develop into a healthy baby embryo competence, it is little wonder that egg development/maturation is a major determinant of human reproductive performance.

A woman is born with all the eggs she will ever produce. She uses them up through her reproductive life and when they are gone, her reproductive potential ends. It is interesting that a woman’s eggs are already stored in her ovaries 6 months before she is born. In fact, she starts losing her eggs at a furious rate from the get-go such that by the time she is born, more than half of her eggs have already been re-absorbed.

This process of egg attrition continues after birth but at a slower rate. By the time the woman reaches puberty and begins to menstruate (the menarche) and then ovulate, her egg population has dropped from more than 5 million (at 3-4 months post-conception) to less than 1 million on average. The number of eggs present at the time of puberty when the woman’s reproductive potential is launched is genetically determined.

Sperm Quality

While about 90% of embryo chromosome aberrations result from egg rather than sperm problems, few would argue that since fertilization is the center pin of IVF success, sperm quality is a vital factor. Nevertheless, the advent of intracytoplasmic sperm injection (ICSI) has all but removed male infertility as an impediment to IVF success.

The introduction of ICSI has made it possible to fertilize eggs with sperm derived from men with the severest degrees of male infertility and in the process to achieve pregnancy rates as high, if not higher than that which can be achieved through conventional IVF performed in cases of non–male factor related infertility. The performance of ICSI in cases of “male factor infertility ” has been shown to marginally increase the risk of certain embryo chromosome deletions (leading to a slight increase in early miscarriages) as well as the potential for a resulting male offspring to have male infertility in later life, there is no evidence of any significant increase in the incidence of serious birth defects attributable to the ICSI procedure itself. More relevant is the fact that when ICSI is performed for indications other than male infertility there is NO reported increase in the risk of subsequent embryo chromosome deletions, miscarriages or in the incidence of subsequent male factor infertility in the offspring.

Evaluating Embryo Quality & Selecting the Best Embryos for Egg Transfer

No other factor in the IVF process influences success as directly as choosing the “right” embryo for transfer to the uterus. This is due mainly to the fact that aneuploidy of the embryo, is responsible for the majority of IVF failures. Aneuploidy generally results in either: 1) the failure of the embryo to develop to a stage capable of attaching to the uterine wall, 2) miscarriage after implantation, or 3) a chromosomal birth defect such as Down syndrome. The selection of one or more competent embryos for transfer is thus central to IVF success.

Uterine Receptivity

Just as a plant can’t grow and thrive without first assuring that both seed and soil are good, neither can a pregnancy be successful without both the seed (embryo) and the soil (uterine environment) being ideal. The uterine factors are just as critical to the equation as the quality of the embryo. There are a number of factors that contribute to the receptivity of the uterus including the contour of the uterine cavity, thickness of the uterine lining, and immunologic factors.

The Embryo Transfer

The critical stage that has significant impact on the outcome of IVF is the embryo transfer. This is a rate limiting step in IVF. It takes confidence, dexterity, skill and gentility to do a good transfer. Of all the procedures in ART this is arguably the most difficult to teach. It is a true “ART” and many women fail to conceive simply because this procedure is not performed optimally. With the aid of ultrasound, the fertility specialist will be able to optimally place the embryos in the uterus. Successful clearance of all other hurdles means nothing if there the embryos are damaged, misplaced, dislodged or if they reflux into the cervix, vagina or fallopian tube(s). Symptoms such as uterine cramping or bleeding during, or immediately after or the procedure are indicators of a poor transfer. A problem-free process is so important that we grade all transfers performed at SIRM on the basis of patient comfort, technical difficulty, and the number of attempts required to achieve the successful transfer of all allotted embryos. Embryo transfer is usually performed 72-144 hours after egg retrieval, but the actual time may depend on whether cleaved embryos or blastocysts are being transferred. Embryos that have not attained at least a 7-cell state of cleavage within 72 hrs of egg retrieval are much less likely to progress to blastocysts and implant successfully into the uterine lining.

CONCLUSION

Many patients think that an excellent IVF success rate is 80% or above, and that anything below 50% is poor. Well, did you know that even a young and fertile couple has just a 15-20% chance to conceive naturally in any one month? Women with top chances of IVF success have per-cycle success rates of 40% or higher, while the majority of women have per-cycle success rates of 20-35%. Having this perspective may help you think about trying more than one cycle, and feel less discouraged if the first one doesn’t work.

In reality, your IVF success is affected by many factors in addition to age, such as your height, weight, (body mass index), ovarian reserve tests, sperm count, reproductive history (e.g. the number of pregnancies, miscarriages, etc.), and clinical diagnoses.

 



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