Placental disease and abnormal umbilical artery Doppler waveforms in trisomy 21 pregnancy: A case-control study

The objectives of this study were firstly to determine the proportion of placental pathology in fetuses affected by trisomy 21 (T21) using current pathological descriptive terminology and secondly to examine if a correlation existed between the finding of an abnormal umbilical artery Doppler (UAD) waveform, the presence of T21 and defined placental pathological categories.

This case-control study assessed singleton fetuses with karyotypically confirmed trisomy 21 where placental histopathology had been conducted from 2003 to 2015 inclusive, within a university tertiary obstetric centre. This was compared with unselected normal singleton control pregnancies matched within a week of gestation at delivery. Data included birthweight centiles and placental histopathology. Comparisons of Doppler findings across placental pathological categories were performed using statistical analysis.

104 cases were analysed; 52 cases of trisomy 21 and 52 controls. Fetal vascular malperfusion (48.1% vs. 5.8%, p = 0.001) and maturation defects (39.2% vs. 15.7%, p = 0.023) were more common in trisomy 21 placentas. Compared with controls, trisomy 21 fetuses were more likely to have shorter umbilical cords (p = 0.001) and had more UAD abnormalities. Amongst T21 pregnancies, umbilical artery Doppler abnormalities are associated with the presence of maternal vascular malperfusion.

Fetal vascular malperfusion and maturation defects are more common in trisomy 21 placentas. Abnormal umbilical artery Doppler waveforms are more common in T21 and are associated with maternal vascular malperfusion. Placental disease may explain the increased rate of intrauterine death in T21.