Preimplantation Genetic Screening: Frequency of Down Syndrome Per Maternal Age

Preimplantation genetic screening is a cutting edge diagnosis used on embryos to ensure that they are not carriers of genes that may contain diseases such as the Down syndrome or Huntington's. The PGS is used during the IVF, in couples that are likely to carry genetic diseases or in advanced maternal age.

Advanced Maternal Age and PGS

The preimplantation genetic screening should be used in women that use in vitro fertilization, because the quality of the eggs decreases with aging. This is due to the fact that the number of eggs in the woman's body is limited and each month an egg is released, leaving the body with fewer eggs each year. The body selects the eggs to release each month, prioritizing the eggs that are of a better quality and have a better genetic composition.

Maternal Age and Down Syndrome

The advanced maternal age may result in babies with Down syndrome. The older the mother, the higher the likelihood of having a baby with the syndrome. In mothers between 20 and 25 years old, only 1 in 1,500 babies is born with Down syndrome. In mothers between 25 and 30, 1 in 1,100 babies has the Down syndrome. After the mother is over 30, the frequency of babies with Down syndrome increases each year:

  • At 31, 1 in 900 babies
  • At 32, 1 in 750
  • At 34, 1 in 500
  • At 35, 1 in 350
  • At 40, 1 in 100
  • At 42, 1 in 50
  • After 45, 1 in 25

These results are based on the number of live births of babies to mothers in certain age groups.

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