QuestionI am trying to understand IVF and how it works. I am healthy in my early thirties as in my wife and I had sperm harvested by biopsy as I have been told I have only one healthy kidney despite everyone else in my family having two and that I have one vas that they think may have closed up on its own. Is there a test to see if you have a VAs, the doctor said he felt one but another doctor said he flet none, while yet another said he felt both.
Also once eggs are harvested what are bad embryos are they not multiplying in cells, bad shape, etc.? Are they not implanted because there is a chance it could produce a bad pregnancy which in effect could put the mother's life at risk, the lab told me they are not used because mainly it would not lead to implantation but there are concerns of a bad preganacy.
Also what is natural cycle and is it safe and how many eggs do woman normally get from it. How does that compare to regular IVF in terms of number of eggs and medications. Thanks
AnswerHello Jack from the U.S.,
I presume from the term "vas" that you mean varicocele? Vas is an anatomic term in the testicle as well, which is short for vas deferens. A varicocele can be felt and is a form of dilated vein or varicose vein in the testicle. You would not need a testicular biopsy for this condition, so something else must be going on, and despite having only one kidney, do you only have one testicle?
So let me explain IVF to you. We'll start with the natural cycle first. A woman's natural cycle to achieve pregnancy occurs in the following steps:
1. The ovary is stimulated to grow an egg (mature the egg since the eggs are already there). In this case, several "follicles" (which contain the eggs) are stimulated by only one becomes matured and ovulated. In a natural cycle only one egg ovulates each month.
2. Ovulation is triggered by the LH surge.
3. The egg "ovulates" and leaves the ovary and enters the pelvis.
4. The egg has to find the fallopian tube on one side or the other.
5. If it finds the end of the tube, called the fimbria, it is drawn into the tube. If it does not within 12 hours, it wilts away and the cycle fails.
6. The sperm have to be in the Fallopian tube at this time in order to fertilize the egg.
7. The fertilized egg undergoes a development process whereby it is formed into various stages of the embryo and makes its way down to the uterus.
8. The embryo reaches the uterus and hatches, whereby the inner cells of the embryo leave the shell.
9. The embryo and endometrium (uterine lining) join together in a process called implantation. At this point, the pregnancy test turns positive.
With IVF, the first 7 steps are done, and the body is left to do steps # 8 and 9, which is why pregnancy rates with IVF are so much higher than natural pregnancy rates. In comparison:
1. The ovary is stimulated with fertility medications, but because higher levels of the stimulant FSH are achieved, more than one egg is matured, leading to 10-20 follicles formed.
2. Ovulation is stimulated with HCG, but ovulation is not allowed to occur. Instead, it is timed so that the eggs are aspirated from the ovaries before they can ovulate.
3. Steps #3-7 are then done in a laboratory. The aspirated eggs are either put together with the sperm in a petri dish (conventional fertilization) or the individual sperm are injected into each egg (ICSI) to allow the fertilization process to occur. Usually, 60% or more of the eggs will fertilize. Some won't for various reaons.
4. The embryos are allowed to mature over several days 3-5 days and then placed into the uterus (embryo transfer). Embryos are evaluated using various criteria, but most of the criteria used are currently based on how they look (morphology) such as are they symmetrical or asymmetric, are there adequate internal structures (polar bodies), how many cells are there, are the cells equal in size, are there any fragmentation, etc. This is how embryologist determine good embryos from bad embryos. Currently there is no technology to know exactly which are the best embryos, because the qualities that make up best embryos are chromosomes and internal structures that we cannot evaluate for. So, at this time it is a beauty contest, and the best looking embryos are chosen. Statistically, from numerous studies, it follows that the best looking embryos have the highest chances for successful pregnancy. But that is not absolute. Many patients have had successful pregnancies with bad looking embryos as well, and not gotten pregnant with the good looking ones.
In most cases, if the embryo that is transferred is a "bad" embryo, it will not develop to the point of implantation so that pregnancy will not occur. In some cases, where pregnancy does occur from a bad embryo, which is usually a genetically abnormal one, miscarriage will occur within the first 8 weeks. The human body is very good at distinguishing bad embryos. The only abnormal ones that tend to continue to delivery, such as down's syndrome, is because the genetic abnormality is very slight (only one chromosome abnormality with don's syndrome).
I hope that answers your questions.
Sincerely,
Edward J. Ramirez, M.D., FACOG
Executive Medical Director
The Fertility and Gynecology Center
Monterey Bay IVF Program
www.montereybayivf.com
Monterey, California, U.S.A.
for additional information check out my blog at http://womenshealthandfertility.blogspot.com check me out on facebook and twitter with me at @montereybayivf
