Confined Placental Mosaicism and Intrauterine Growth Retardation

Confined placental mosaicism is the presence of an abnormal cell line in the placenta of a fetus having a normal karyotype. It is diagnosed by the detection of both normal and abnormal cell lines in samples of chorionic villi, while only the normal cell line is detected in fetal blood samples and by amniocentesis. Uniparental disomy refers to the transmission of both members of a homologous chromosome pair from the same parent and can be present together with confined placental mosacisim. The prevalence of confined placental mosaicism in the population of idiopatic intrauterine growth retardation varies between 15.7% and 25%. Confined placental mosaicism is also associated with oligohydramnios, spontaneous abortion and fetal loss. Intrauterine growth retardation is most commonly reported in confined placental mosaicism for chromosomes 2,7,15 and 16 and in uniparenteral disomy for chromosomes 7, 11, 14, 15 and 16. It is not known whether growth retardation in uniparental disomy cases evolves as a result of the placental mosaicisim or of the uniparental disomy itself. In this paper, we aimed to summarize the relationship between confined placental mosaicism and intrauterine growth retardation by reviewing clinical studies and case reports on this topic. (Marmara Medical Journal 2012;25:109-13)