The regulation of trophoblast differentiation, proliferation and invasion via Notch signalling in the human placenta is not yet known exactly. In mammals, this basic pathway uses four membrane-bound receptors (Notch 1-4) and five different ligands (Jagged 1, Jagged 2, Delta-like ligand 1, Dll3 and Dll4), whose interactions initiate transcriptional activation of several target genes. It was found that Notch 1 signalling modulates uterine decidualisation, and that Notch members are activated in subsets of trophoblasts. Therefore, the defect of the Notch signalling pathway contributes to pregnancy complications. That’s why this paper focuses on the expression and function of Notch 1 in human first trimester placenta. In order to identify the influence of Notch 1 on proliferation and motility of human trophoblast cells, analyses with the immortalised SGHPL-5 cell line were performed. To analyse the consequences of the inhibition of Notch receptor 1 in human placenta, experiments with first trimester explant cultures were conducted. Apart from that, immunofluorescence staining of hydatidiform moles and age-matched placentae were performed, in order to compare the expression of Notch 1. The results suggest that the inhibition of Notch receptor 1 enhances the motility and reduces the proliferation of SGHPL-5 cells. The immunofluorescence analysis shows a higher expression of Notch 1 in hydatidiform moles, compared to the age-matched healthy placentae.