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Tuesday, November 6, 2012

Can an EmbryoScope help me in achieving IVF success?





Why is embryo selection important in the field of ART ?

Not all embryos which are transferred to the uterus implant and develop into a healthy baby. This shows that not all embryos are equal in their developmental competency. Fewer than 2 out of 10 embryos actually implant. This scenario underlines the importance of embryo selection before transferring them to the uterus. An ideal IVF cycle would produce a live birth when a single embryo is transferred to a receptive uterus. But even after 3 decades of IVF invention we are still far away from an ideal IVF cycle. Most clinics around the world have a success rate of 40-50% per cycle and this means the chance of failure when undergoing an IVF cycle is higher than the chance of success. During an IVF cycle several embryos are produced. The embryologist normally selects the best looking embryo(s) to be transferred to the uterus. The remaining embryos which are viable are frozen and are transferred to the uterus during the subsequent IVF attempts. How does an embryologist decide which embryo(s) should be transferred to the uterus?  There are a set of well-defined rules for selecting the best embryos (the embryos which are viable and most likely to implant) based on their morphological appearance under the microscope. Depending on those criteria, embryos are graded, the best ones are selected and are transferred to the uterus. But this technique is not fool-proof ! Fifty to sixty percent of the time , even the best looking embryo (called a top quality embryo, selected based on the embryo grading rules) fails to achieve a pregnancy. On the other hand, sometimes less than optimal looking embryos implant and give rise to a healthy baby.  If we are able to correctly pin-point which embryo will implant ( by being able to assess the developmental competency of an embryo accurately !) and become a baby then the success rate of an IVF cycle will greatly improve. A good embryo selection technique will be able to reduce the time taken to achieve a viable pregnancy when undergoing ART, even if it doesn’t lead to a 100% success rate.

What criteria should a good embryo selection tool have?

A good embryo selection technique must provide meaningful (it should be possible to make use of this information in routine clinical practice), quantitative information and should be non-invasive. It must be able to differentiate between ‘viable’ and ‘non-viable’ embryos as well as ‘normal’ and ‘abnormal’ embryos. For example an embryo which is viable need not always be genetically normal. Many viable embryos implant but fail to produce an ongoing pregnancy  because they are genetically abnormal . On the other hand , if the embryo is not viable , then it fails to implant and achieve a pregnancy.

Why don’t all the embryos produced via IVF implant and develop into a baby?

This is a million-dollar question ! Scientists are trying hard to decipher this puzzle. As per the present state of our knowledge, there are two major reasons for the failure of an embryo to implant:

1)      Lack of genetic competency in embryos

It has been found that 50 – 60 % of embryos created via IVF are genetically defective. Women of Advanced Maternal Age (AMA) produce an even higher percentage of genetically abnormal embryos. Such embryos are called aneuploid. Aneuploid embryos carry an abnormal number of chromosomes in them. Chromosomes are the structures which carry the genetic information necessary for creating a healthy baby. Abnormal chromosome number leads to abnormal genetic content which in turn prevents the ability of an embryo to implant and develop into a healthy baby.

2)      Lack of  receptive endometrium

The endometrial layer ( the uterine lining) plays an important role in embryo implantation. For the embryo to implant, a successful cross-talk between the endometrium and the embryo has to take place. If the endometrium fails to express proteins which are crucial in assisting embryo implantation, then even if the embryo is genetically competent , it will fail to implant in the uterus.

So, for an embryo to implant and develop into a baby, it has to carry accurate genetic information and the endometrium should be receptive enough to allow it to implant and grow.

What are the methods which are employed in the field of ART to select the embryo which is more likely to develop into a baby?

The most widely used method or ‘traditional’ method for embryo selection is based on assessing the morphological appearance of an embryo under the microscope (embryos are graded according to their cell number, amount of fragmentation and cell size). You can learn here how the embryos are graded according to their morphological appearance. The bitter truth is that not all ‘perfect’ looking embryos survive in utero and become a baby. On the other hand, sometimes even the worst looking embryo can give rise to a beautiful baby. Since looks can be deceiving, as always, there is a need to develop techniques which could accurately say whether an embryo is viable and competent enough to develop into a baby or not. At present there are two new developments which promises to increase the success rate of IVF. The first one is called comprehensive chromosome screening. This technique screens all the 23 chromosomes of the embryo for genetic abnormalities and thus helps in selecting embryos which are genetically normal. Since genetic incompetency of the embryo is said to be the main reason for IVF failure, this technique theoretically should improve IVF success rate. But this technique is invasive by nature and still in its infancy. Further clinical trials are necessary to determine whether CCS is a panacea or a pipe dream. You can read my blog post about CCS here.

There is one more recent invention which promises to increase IVF success rate by improving embryo selection criteria and this technique is based on time lapse embryo imaging. The instrument which is used for this purpose is called an EmbryoScope.

What is an EmbryoScope ?

A new technological advance which promises to improve IVF success rate is an EmbryoScope. It is an incubator (an instrument which maintains ideal temperature, humidity and proper oxygenation in order to support the optimal growth of embryos) with a built-in camera which can be used to monitor the growth of the embryo continuously without the need to remove them from their cosy culture conditions. The EmbryoScope thus provides a time-lapse , slow-motion picture of your embryo’s growth, minute by minute.

What information does an EmbryoScope provide ?

EmbryoScope provides information about an embryo’s morphokinetics (changes in morphology with time). It can be used to monitor the embryo’s development , minute by minute , and is capable of generating several images of embryos growth over a period of time. As a result an EmbryoScope can give details like - the time taken from fertilization to the first cell division; time taken to complete first cell division; time period between the subsequent cell  divisions; how many cells the embryo had at a particular time point; details about the cell nuclei and so on.

How useful is the information generated using an EmbryoScope  ?

The company which developed the EmbryoScope and many IVF specialists who own it claim that an EmbryoScope can improve IVF success rate. It is true that an EmbryoScope generates hundreds of beautiful pictures of an embryo’s growth. But how useful are these pictures / data in real life ?  For example, if an EmbryoScope is programmed to take pictures of an embryo every five minutes and if the embryo is monitored continuously for 3 days, then the instrument generates 864 pictures of an embryo, during its different stages of development. How will these pictures help in determining an embryo’s developmental competency? The company which sells the EmbryoScope provides software into which these pictures are fed . The software then says whether the particular embryo complied with the ‘optimal cell division rules’ during its development.  The key question is – how many randomised clinical trials ( not sponsored by the manufacturers) have been done to study the utility of the Embryoscope ? What is the proof that it is better than the ‘traditional’ method of embryo grading which relies on five or six single conveniently scheduled observations during its in vitro development ?  There are lots of unanswered questions and a lot more has to be done before someone can claim that EmbryoScope can improve IVF success.

Will the EmbryoScope help me in achieving IVF success?

As patients, we should welcome any new technological advance with utmost caution. Already the field of IVF is plagued with flawed technologies, flawed analysis and erroneous conclusions which affect us – the patients. We should not forget that the main aim of the company which sells this instrument ( and of the IVF clinics which buy this costly instrument ) is to sell this technology and reap a profit. As patients, our main aim should to get a baby with minimal expenditure. So if you are lured into selecting an IVF clinic based on their promise to use an EmbryoScope for improving the IVF outcome , you need to be careful. This is true especially if you have poor ovarian reserve or if you are a poor responder to IVF drugs and yet the IVF specialist promises that ‘come to us because we have an EmbryoScope, and can use it to help you in attaining success’ . The best thing you can do is to avoid that clinic because this clearly shows that even the IVF specialist is himself not aware of the limitations of an embryoscope or he just wants to earn more money. Remember, an EmbryoScope cannot give you more embryos or better quality embryos. It is just an instrument to select better quality embryos. The truth is that the selection criteria for embryos using an EmbryoScope are not well-defined at the present moment. A poor responder normally produces few embryos and what is the point of subjecting those embryos to monitoring using an EmbryoScope ? With few embryos , selection often becomes unnecessary because beggars cannot be choosers, and the doctor has very limited choices in the first place, because of the paucity of embryos !

At present, the EmbryoScope is a novel technological advance which might or might not prove to be helpful in improving IVF success. It is definitely not a magical solution for conceiving a baby via IVF. Until then , an EmbryoScope is just an instrument which provides beautiful pictures of your embryos - and if you have to do it for an added cost , it is definitely not worthwhile to use it!

2 comments:

  1. One thing i wud ask if u can share incidents or feelings abt gud n bad things happen in ur life, if u want to share only then.

    ReplyDelete
  2. Fertility treatments have come up as a hope many couples. They have helped a lot number of people in bringing their bundle of joy in this world and attain motherhood. Though, it is said that not all fertility treatments are suitable for women who are trying to conceive. Treatments of fertility mainly depend on the cause, age, for how long one has been infertile and many other personal preferences.

    ReplyDelete

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