Placental apoptosis in normal and abnormal pregnancies

The aim of this study was to demonstrate apoptosis in the human placenta in normal and abnormal pregnancies. The percentage of apoptotic cells in placental samples was quantified by analyzing the cell cycle of nuclei stained with propidium iodide using a flow cytometer. No significant difference in the percentage of apoptotic cells was observed comparing the group of normal pregnancies (first and second trimesters) with those of missed abortions. There was also no difference in the incidence of apoptosis comparing placental samples obtained from chromosomally normal and abnormal pregnancies. Yet, there was a significant increase in the incidence of apoptosis in placental samples obtained from second and third trimesters as compared with those obtained from the first trimester (p<0.04 and p<0.01, respectively). There was also a significant increase in the incidence of placental apoptosis in the third as compared with the second trimester (p<0.03).