Maternal age specific chromosomal abnormalities at amniocentesis

Abstract

Suttleworth (1909) suggested that with regard to parentage, the significant etiologic factor would be the advanced age of the mother at the birth of the child. For the past thirty years, advanced maternal age (>35 years) has been the single most important criteria used to rule-out chromosomal abnormalities. Risk estimates in such populations has become an important denominator for physicians or obstetricians and numerous studies have been compiled. Since May 1997, we evaluated 1126 cases and found 27 cases cytogenetically abnormal. Eight cases were diagnosed with trisomy 21 (30%) two with trisomy 18 (7.4%) one with trisomy 13 (3.7%) 5 cases (18.5%) with various chromosomal abnormalities while the remaining have had balanced or unbalanced translocations (40.7%). The over all frequency of chromosomal abnormalities for the advanced maternal age group was 2.4%; 40.7% were structural while 29.6% were trisomy 21. We are in the process of compiling data from various centers that shall be useful during pre- and post genetic counseling. Certain religious groups do prefer counseling only; and would not go for genetic amniocentesis. For such groups, information on the risks and incidence for various chromosomal abnormalities, should serve as an educational tool.