Background: First trimester trophoblastic invasion has far-reaching consequences for the fetus; failure at this stage may result in fetal growth restriction with morbidity both in the immediate perinatal period, as well as throughout development into adulthood. Objective: The aim of this study was to estimate the placental thickness in first trimester (11-14) weeks and investigating the correlation with preeclampsia and intrauterine growth retardation. Patients and methods: This prospective cross-sectional study was conducted at Al-Azhar University Hospital. The study included 50 patients. Results: There was a significant increase in the maximal placental thickness (PT) to placental volume ratio in growth restricted fetuses in our study. This may be a reflection of reduction in placental surface area. Further work is required to confirm this finding using more accurate stereological analysis of the placenta in utero. In this study, the MRI appearance of suspected retroplacental haemorrhage, placental infarct, and subchorionic haemorrhage was confirmed by placental histology in 100%, 100%, and 33% of cases respectively. Conclusion: From our study, it can be concluded that PT can be used as a predictor of the GA, in the women in whom the LMP is unreliable or is not known