ObjectivesThe aim of this study was to evaluate placental apparent diffusion coefficient (ADC) values, obtained by diffusion-weighted imaging (DWI) in uncomplicated pregnancies and pregnancies complicated by Fetal Growth Restriction (FGR). MethodsWe retrospectively evaluated 1.5T placental magnetic resonance imaging (MRI) from 38 singleton pregnancies. In the DWI sequence, (bvalue 200, 400 and 1000 s/mm2) regions of interest (ROIs) were drawn, covering the entire placenta in five placental slices and mean ADC values were calculated. In normal pregnancies delivering neonates ≥ 2.3rd percentile, the relation between ADC value and gestational age at time of MRI was estimated using ordinary linear regression. In FGR pregnancies, ADC z-scores were calculated.Results31 pregnancies (20 to 37 weeks of gestation) resulted in the delivery of neonates ≥ 2.3th percentile. In these pregnancies, placental ADC ranged from 1.33 to 1.76 x 10-3 mm2/s, with significant inverse correlation between ADC values and gestational age (p=0.001). In seven pregnancies (27 to 37 weeks of gestation), resulting in neonates < 2.3th percentile, the placental ADC z-scores were between 1,10 and -2,80. In three FGR cases, ADC value were significant reduced. However, in the remaining four FGR cases, it was within the normal range.ConclusionIn normal pregnancy, placental ADC value, is reduced with advancing gestational age. However, the pathological abnormalities of the failing placenta in FGR, seems not to affect the ADC-value.