Confined placental mosaicism and intrauterine growth retardation: a case-control analysis of placentas at delivery.

OBJECTIVE

Our purpose was to determine the frequency of confined placental mosaicism in newborns with unexplained intrauterine growth retardation compared with infants with appropriate in utero growth.

STUDY DESIGN

Amnion, chorion, and villi from 12 growth-retarded infants and 24 appropriately grown, matched controls were karyotyped. Fluorescence in situ hybridization with chromosome-specific probes was then used to confirm the karyotypic abnormality at additional uncultured placental sites.

RESULTS

Karyotype analysis revealed placental mosaicism involving either aneuploidy or polyploidy in three of 12 (25%) cases versus two of 24 (8.3%) controls. Fluorescence in situ hybridization confirmed the karyotypic abnormalities in the placentas from growth-retarded infants only.

CONCLUSION

Confined placental mosaicism was identified three times more frequently from placentas of growth-retarded infants compared with those of newborns with appropriate growth. Molecular studies of the placentas suggested a wider distribution of cells with abnormal karyotypes in cases compared with controls and support a biologic influence of placental mosaicism on fetal growth.