In this regard, it is good to first have an understanding of the procedure itself before delving into further details.
In Vitro Fertilization – What is it?
Developed by Dr. Robert G Edwards who was awarded the Nobel Prize for Physiology in 2010, the process of in vitro fertilization is a part of what is called an assisted reproductive technology (ART). It is a process for couple who fail to conceive due to infertility. In this process, the woman’s egg is fertilized with a sperm outside the body – in a laboratory dish. This is then implanted in the uterus is called in vitro fertilization. The word in vitro comes from a fertilization of the egg externally, in the laboratory – the term ‘in vitro‘ is a Latin for ‘within the glass‘, since all laboratory apparatus earlier was made of glass unlike today.
Factors determining the success of IVF
The process of in vitro fertilization may be preceded by the use of fertility drugs to regulate the reproductive hormones and trigger the release of one or more of eggs per ovulation cycle. Controlling ovulation by administering hormones, the ova are removed from the woman’s ovaries and fertilized externally with a sperm donated by the male.
While trying the in vitro fertilization process, the ovaries response greatly varies when women are given the FSH injectable drugs for stimulating the ovaries. At the procedure for retrieval of eggs, a range of eggs is retrieved and antral follicle counts are the best way to predict the ovaries response and the numbers of eggs that can be retrieved. This needs to be taken into account before we stimulate the woman with the FSH. To a certain extent, the chances that IVF will be successful depend on the numbers of eggs that one has to work with. The chances here are: if there are more eggs, they will likely give us more numbers of good quality embryos for the procedure involving transfer of embryos. Essentially, this is an issue of the selection of embryos and this is the reason why it matters.
Embryo quality and IVF embryo grading
The likelihood of developing high quality embryos depends heavily on having better egg quality. We will discuss some more on the quality of eggs and the issues of egg quality related to ovarian reserve and supply of eggs below. It has been studied that women –
- Less than 35 years of age have the most rates of success in all of the “egg number” groups
- Less than 38 years of age have acceptable rates of live birth even with 3 – 6 eggs only; things are better when there are more than 6 eggs and the best when there are more than 10 eggs
- who are in the 38-40 and 41-42 years old, with egg numbers being low have live birth rates that are low
- when the egg numbers obtained are relatively high, there are much better success rates
- with fewer than 3 retrieved eggs, women of all age groups have success rates that are very low
Typically, there is a decrease in the quality of eggs with an increase in the age of the woman and, due to the lower quality of eggs, as women grow older the eggs need is more for IVF to work. For this reason, woman are stimulated at the IVF centers so as to obtain sufficient eggs. The idea is not to get more eggs so that we can transfer more embryos, the idea is to get “enough eggs” to combat the drop-off that occurs when some embryos arrest their development. This is a process that is normal and doing the above ensures that at least one or two good ones are available to transfer to the woman.