Wednesday, December 22, 2021

Why doesn't IVF have a 100% success rate ?


What can we do to make sure our IVF cycle will succeed ? This is a question many IVF patients ask. After all, if we are making embryos in the IVF lab, then shouldn't the embryo always become a baby  when we put it back into the uterus?

I wish this were true - it would make my life so much easier ! I would then just have to tell patients to pay my fees, so they could take home their baby with them!

Jokes apart, we need to understand that the IVF success rate is limited not by medical technology but by the basic biological fact that human reproduction is not very efficient. Let's not forget that even a very fertile couple takes quite some time to make a baby in their bedroom . Only about 20% of couples will get pregnant in one month , even if they have sex every single day . This is called the fecundity rate , and we also know that out of 10 couples , 9 will take up to one year in order to get pregnant in their  bedroom , no matter how frequently they have sex .

This is why the definition of infertility is restricted to couples who fail to get pregnant in their bedroom, even after trying for at least a year . The truth is that even fertile couples need to be patient in order to get pregnant , and going to an IVF clinic doesn't change that fact . Of course, it is far easier and much more fun ( and much less expensive !)  being patient in your bedroom as compared to being a patient in an IVF clinic , but either way , you really don't have a choice .

This is because the rate limiting factor for success in an IVF cycle is not the clinical treatment we provide , but the fact that after we make the embryo and then transfer it back into the uterus , we have no control over whether it's going to implant or not. This is because embryo implantation is still a black box area , which we can't monitor or control . We do know that most embryos do not become babies, whether they are made in the bedroom ( in vivo) or in the lab ( in vitro). This is because most embryos have genetic errors, and these are random . Some of these are lethal, which is why these embryos arrest and can't develop any further. The difference is that this is a silent process in the bedroom, and women are blissfully unaware of the number of embryos that die in their uterus every month. 

In fact, IVF actually increases the natural fertility rate . Nature's fertility rate is about 20% , and in an IVF cycle for patients who are good ovarian responders, we can increase this to 40% by helping the woman to grow many eggs, and selecting the best blastocyst to transfer.

However, while we can control the process of superovulation and how we grow the embryos in the IVF lab,  the fact remains that after we transfer the embryos back into the uterus, we have no control over what happens to them .

This is frustrating for patients - for doctors as well, because we want all our patients to get pregnant as quickly as possible, and it breaks our hearts when they don't, in spite of our best efforts  !

 Need help in getting pregnant ? Please send me your medical details by filling in the form at so that I can guide you !


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