How does age affect IVF success rates ?

Pregnancy and live birth rates following ART decline with increasing age. Based on SART data.

Alviggi et al. Reproductive Biology and Endocrinology 2009 7:101   doi:10.1186/1477-7827-7-101

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 50-80 %.  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.

Read more at : http://www.drmalpani.com/infertilityintheolderwoman.htm