Preeclampsia is a heterogeneous disease, and there are major differences in severity, fetal growth and poor placentation between early- and late-onset preeclampsia. Here, we examined the effect of onset period on fetal and neonatal growth in preeclampsia with a cross-sectional study including 102 pregnant women with preeclampsia visited Okayama University Hospital from 2009 to 2013. The subjects were retrospectively compared in terms of body mass index (BMI), weight gain during pregnancy, complications, weeks of delivery, neonatal body weight and BMI at birth, fetal growth restriction (FGR), small for gestational age (SGA), pathological findings in the placenta, and infant’s weight at 1 month after birth. Neonatal body weight and BMI at birth were significantly lower and the extent of FGR and the frequency of SGA were higher in early-onset group compared with late-onset group. Mean daily weight gain during the neonatal period was significantly lower in the early-onset group compared with the late-onset group, however the weight gain rate during the neonatal period in the early-onset group was higher than that in late-onset group. In conclusions, there are significant differences in fetal and neonatal growth between early- and late-onset preeclampsia and the catch up for growth might start during neonatal period.