In an earlier post, we looked at the world explosion in the number of healthy babies born through IVF, gradually improving in the past 25 years and rapidly so in the past 10 years. But what exactly is the concept behind the success of IVF? How does it help so much?
Recall our past discussion regarding how to make a baby. You need to start with the two components: the sperm and the egg. To have a baby, you need to have a genetically perfect sperm unite with a genetically perfect egg. In nature, the way this happens is the egg emerges from the ovary during the process of ovulation. Then it will float around freely inside the abdominal cavity waiting for a chance to be picked up by the Fallopian tubes.
You know those things that they use to automatically clean swimming pools. They float around on the surface and randomly suck up leaves and debris? The Fallopian tubes work a lot like that. After ovulation, the egg floats in a thin layer of fluid. Imagine if you will, tossing a ping-pong ball into a swimming pool and waiting for the pool cleaner to suck it up. Eventually, given enough time, that sweeper will make its rounds throughout the entire pool and suck up everything. However, eggs have a limited life span of less than 24 hours. So in our pool analogy, imagine if the ping-pong ball was set to self-destruct in 2 hours, that would make it unpredictable whether it would make it into the sweeper before that time was up.
So IVF helps in at least three ways.
1. The sperm and egg are physically brought together for sure. This is a big advantage. No longer do you have to rely on the tubes to suck up the eggs. This is especially important in patients with blocked tubes or with extensive endometriosis or pelvic adhesions (scar tissue)
2. With, IVF, we start out with multiple eggs instead of just one so there is a much higher likelihood that at least one of the sperm-egg pairings will consist of perfect sperm and a perfect egg coming together.
3. The sperm can be directly injected to fertilize the egg. Without help, even if the egg makes it into the Fallopian tube, and there is sperm waiting, that does not guarantee that a sperm will actually fertilize it, either because of failure to physically collide or because of deficiencies in the sperm that make it less capable of entering the egg.
IVF is a great treatment for infertile couples with tubal problems or severe sperm problems. It is also a good backup plan for times when everything else fails.