Loss of ovule quality becomes especially relevant at 40 years of age, when a high proportion thereof, and therefore of the embryos available for transfer, may show chromosomal alterations.
Most of these abnormal embryos either will not produce a pregnancy or will end in pregnancy loss, but some may evolve producing children with serious malformations or mental retardation.
After 40 years of age, over 65% of embryos are altered.
Assisted reproduction laboratories have tools such as the time lapse system or the long-term culture, which allow selecting the embryos with the least chance of showing chromosomal anomalies. But apparently healthy embryos can show alterations that are not detectable by these systems, especially in older patients.