ENLARGEMENT OF CISTERNA-MAGNA AS AN INDICATOR OF CHROMOSOMAL-ABNORMALITIES IN A LOW-RISK ASIAN POPULATION

Aims: The aims of this study was to invent the prevalence of cisterna magna (CM) enlargement in a low-risk population and relate this to chr omosomal abnormalities and initial delivery outcome. Study design: 11, 145 patients having routine ultrasound scan at 21st week of pregnancy were screened for abnormalities. Cases with CM enlargement were traced and outcome retrieved either from case notes or from the patients. Re sults: In our low-risk population six fetuses were found to have CM en largement. Only one had a chromosomal abnormality, 47XY+18, and this f etus also presented with other malformations. Four were healthy at bir th and one, also with other malformations, is showing signs of mental retardation. All cases were male. Conclusion: Isolated CM enlargement does not seems to be an indicator for chromosomal abnormalities, espec ially if the fetus is a male. Still, it should alert the examiner of t he possibility of other malformations, which may be of importance.