Confined placental mosaicism as a risk factor among newborns with fetal growth restriction

To delineate the frequency and clinical presentation of confined placental mosaicism (CPM) among newborns with idiopathic intrauterine growth restriction (IUGR) as compared to infants with appropriate fetal growth.

70 newborns with IUGR (birth weight < 10%) were matched by maternal age (+/-5 years) and gestational age (+/-7 days) to an equal number of infants of normal size. From both populations, placental samples underwent karyotype analysis following standard culture.

CPM occurred significantly more often in the placentas from IUGR infants compared to controls, 11/70 (15.7%) and 1/70 (1.4%) respectively (p = 0.008). High-level tetraploidy (>20% in a primary culture) predominated among the IUGR placentas, while autosomal aneuploidy occurred only once in each population. Placental histology revealed significantly greater decidual vasculopathy, infarction, and intervillous thrombus formation in the karyotypically abnormal placentas (p = 0.03). Maternal age, gestational age at delivery, degree of growth restriction and ponderal index did not vary with the presence of CPM.

CPM, and principally high-level tetraploidy, is found significantly more often among the placentas of newborns with IUGR. Infants with IUGR and CPM are clinically diverse although the placentas display pathologic changes suggestive of chronic impairment of uteroplacental function.