Author(s): Leopold ?liwa, Barbara Macura
It is a well-known fact that elderly women are in higher risk of having children with inherited defects of various etiologies. The precise reasons for this phenomenon are unknown. One of embryological hypotheses tries to explain this fact. During oogenesis, germ line cells are formed during prenatal life and remain in cytological stability in postnatal life. This is when the mutations caused by environmental and endogenous factors accumulate and deteriorate their genetic quality. Furthermore, the predetermination of cell numbers during prenatal life limits future reproductive capabilities of women. These facts underlie the “evolutionary grandmother hypothesis” which explains the peculiarity of women’s reproduction. According to this hypothesis, elder women give up their reproduction to take care of related children. Recently, attention has been paid to progressing decline in the interaction between the mother and fetus in older women. It consists in the impairment of mechanisms that regulate natural intrauterine selection of defected fetuses. As a result, enhanced maternal tolerance to abnormal embryos is observed. These observations define the “closed door hypothesis” and clarify higher incidence of inherited defects in children of elderly women.