OBJECTIVE: The application of magnesium during pregnancy is a controversial issue. Beyond evidenced-based indications for the use of magnesium as preeclampsia, numerous dubious indications exist. Anyhow the effect of magnesium on the placenta is little-known. First studies on the topic suggest an apoptosis-inducing effect of magnesium. METHODS: Placental explants from 22 placentas were incubated with extracellular magnesium concentrations from 0 - 2.0 mM. Placental apoptosis was evaluated by tissue morphology, cytokeratin-18 neoepitope formation in immunohistochemistry and Western blotting, TUNEL-Test and DNA-Laddering. RESULTS: Magnesium stimulated a concentration- and time-dependent placental apoptosis. In particular magnesium concentrations over 0.7 mM led to apoptotic changes. After removal of the explants the media with higher extracellular magnesium concentrations displayed apoptotic and aponecrotic fragments and cell-free DNA. CONCLUSION: Magnesium induces apoptosis in the trophoblast. It is known that an increased apoptosis rate is part of the pathogenesis of preeclampsia. Hence, the application of magnesium during pregnancy, especially for preeclampsia, should be considered well and strictly follow evidence-based criteria
