IVF- FAQs - How does age affect IVF success rates ?
Posted Mar 21 2013 10:17pm
This is part 1 of our IVF-FAQ series.
The woman’s age is the most important prognostic factor which determines IVF success. In sharp contrast, the age of the man doesn’t have a significant impact on the outcome of an IVF cycle. Pregnancy and live birth rate after IVF decline with increasing maternal age because the success of an IVF cycle depends on the number of eggs that can be harvested from the ovaries and their genetic quality. As a woman ages, her ovaries age too and old ovaries have poor ovarian reserve. Ovarian reserve is defined by the number of usable eggs left in the ovaries. Aging cause two significant changes in a woman’s ovaries
1. The number of eggs present in her ovaries decreases ( All the eggs that are present in a woman’s ovaries are formed when she was a fetus. Ovaries do not have the ability to produce new eggs and hence we do not know how to renew egg supply once this is exhausted !) 2. The quality of eggs (their genetic competence and mitochondrial quality ) remaining in her ovaries becomes poor too.
As a result, women of Advanced Maternal Age (AMA) have a poor chance of success with ART treatments. Even if they achieve a pregnancy, the chance of miscarriage is greater than 50% for women who are above 40 years old as compared to the miscarriage rate of 12% for women of 20 years. This high miscarriage rate is due to the presence of chromosomal abnormalities in older eggs. Eggs from older women have higher rates of anueploidy (the presence of wrong number of chromosomes ) and hence the embryos formed from such eggs are genetically incompetent . They often fail to implant ; and even if they do implant, they fail to give rise to a live, healthy infant.
After the age of 40, women have about a 10 % chance of conceiving per IVF cycle ; and even if they do the chance of miscarriage is as high as 50 %. When an older woman uses eggs form a young woman (donated eggs), her chance of conceiving and having a successful pregnancy is as high as that of the young woman ! This indicates that the implantation and developmental potential of an embryo depends mainly on the age of the oocyte , and not on the age of the uterus ! This is why surrogacy is not usually be a reasonable solution for failed IVFs – most of the time the embryos do not implant because of a problem with the embryos (because of genetically incompetent eggs !) and not because of an incompetent uterus.
We do not have an upper age limit, provided you have realistic expectations ! If you are an older woman and are going in for IVF treatment using your own eggs, you should clearly understand the scientific facts. This will help you to analyze the pros and cons and make a well-informed decision. If you are above 40 and would like to try with your own eggs , you have every right to do so provided you are well-informed. The drawbacks of using old eggs are
• The chance of retrieving a decent amount of good quality eggs from an older ovary is low , as a result of which there is a higher chance of IVF cycle cancellation. • There is a higher risk for complete fertilization failure – your partner’s sperm might fail to fertilize your eggs because of the changes in your eggs due to old age. • Even if fertilization occurs and embryos are formed , more of your embryos have a chance of being genetically abnormal. There is a higher risk of miscarriage because of this • The risk of having a genetically abnormal child ( such as a baby with Down syndrome) is much higher as compared to a younger woman
As you age , your response to ovarian stimulation and likelihood of a live birth decreases. If you understand the above facts clearly , and then decide to make a well informed decision , we will be happy to help !
This is an excerpt from our forthcoming, book, The Expert Patient's Guide to IVF. This being authored by our expert patient, Manju and me.