“How many children are you and your wife going to kill, to get the one you want?”
Even with normal sex, a fertilized egg has only a 30% chance of implantation.
Basically, almost 3 “lives” are lost for every birth.
Live birth per embryo transfer
Phew! We’ve gotten this far, but it still feels like a numbers game! The most important question to ask at this stage is “What is the chance of a baby each time we transfer an embryo?” The fuzzy answer is that successful embryo implantation is a very intricate and complicated process. And the bottom line is that an euploid embryo has a better chance.
Our expectation: Transfer of an untested blastocyst results in a live birth of about 40-50% each transfer, with a miscarriage risk dependent on the mother’s age. However, your chances are better with a genetically normal, euploid blastocyst which results in pregnancy about 65% of the time with a 10% chance of miscarriage. Transferring two embryos, surprisingly, does not increase the live birth rate. Rather, it only increases the chance of a high-risk twin pregnancy. Ideally, we will only transfer one embryo for the best chance of a healthy pregnancy.
Let’s do the math!
So, we’ve set out our expectations for an IVF cycle, now let’s put the math to work in a hypothetical example with a woman who is under 35 with normal ovarian reserve.
Let’s say that at her egg retrieval ultrasound she has 30 follicles over 16mm. Our expectation is that of those 30 follicles, 80% will have eggs in them, leaving her with 24 eggs. Of those 24 eggs, our expectation is that 80% of these eggs will be mature and able to be fertilized. She now has 19 mature eggs ready for fertilization.
At fertilization, 80% of these eggs fertilized normally, so she now has 15 fertilized eggs ready to be cultured and grown to blastocyst stage. But only 40% of her fertilized eggs make it to 5 days, leaving her now with 6 blastocysts ready to biopsy for PGT analysis. After biopsy, 4 embryos test euploid and are ready for transfer in separate single embryo transfer procedures. Each transfer of a euploid embryo gives her a 60-70% chance of conceiving. And, after 4 separate transfers, she could hypothetically have between 2 and 3 children born through IVF.
https://www.fertilityanswers.com/is-ivf-a-numbers-game/