Birth Defects in Older Women: Older women tend to give birth to a child with birth defects which occur due to aneuploidy and polyploidy. Besides that, they tend to undergo miscarriage or stillbirth. Aneuploidy and polyploidy occur mostly because of non-disjunction of the chromosome during meiotic anaphase-I. The chances of non-disjunction of chromosomes increase with maternal age. It has been suggested that the weakening of sister-chromatid cohesin - a protein that holds the sister chromatids together -might be the reason of the non-disjunction of chromosome (Hodges et al., 2005). Bickel and colleagues have shown that fly oocyte that has a defect in sister-chromatid cohesin shows such effects in the segregation of non-exchanged bivalent chromosomes. Even if crossing over has taken place in meiotic metaphase-I, such dysfunctionality of cohesion still might appear in older women. (Jeffreys et al., 2003)