Histopathological or clinical features do not predict the presence of high level tetraploidy as a form of confined placental mosaicism in pregnancies affected by otherwise idiopathic IUGR

Abstract

<h3>Aims</h3> Confined placental mosaicism (CPM) is a risk factor for intrauterine growth restriction (IUGR). We investigated if we could identify pregnancies affected by high level tetraploidy (>22% of metaphases) as a form of CPM (TCPM) by clinical or placental histological features, within a larger group of pregnancies affected by IUGR of unknown origin. <h3>Methods</h3> Placentae from pregnancies affected by IUGR of unknown cause over a period of 28 months were karyotyped: 12 of 52 placentas showed TCPM. Maternal age, gravidity, parity, pre-pregnancy body mass index (BMI), and placental histology were compared between IUGR affected pregnancies with or without TCPM. Placentas with other karyotypic abnormalities were excluded from analysis. <h3>Results</h3> Parity, gravidity or maternal age showed no significant difference. IUGR without TCPM mothers tended to have a slightly but significantly higher BMI. Placental histology failed to show a significant difference with regard to the presence of abnormality or the type of parenchymal abnormality identified. <h3>Conclusion</h3> The presence of TCPM in IUGR cannot be predicted by either clinical or histological factors. Karyotyping of all placentas from pregnancies with apparently idiopathic IUGR may be advisable to identify this cause of IUGR.