[Additional magnesium therapy in tocolysis: clinico-chemical monitoring parameters].

Pregnancy can result in magnesium deficiency, which may precipitate premature labour usually reversed by betamimetic therapy. Inclusion of magnesium in tocolytic therapy is useful for possible reduction of premature labour as well as for cardioprotection. 35 patients with premature labour received Fenoterol + 20 mmol/day magnesium aspartate hydrochloride (Mg-asp-HCl) orally or 30 or 40 mmol/day Mg-asp-HCl and magnesium sulphate (MgSO4) (1:1) i.v. Before and during this therapy, Mg, Ca, K, Na, Cl, creatinin and urea as well as human placental lactogen (HPL) and oestriol (E3) were determined. There were no significant changes in the level of these under oral magnesium therapy. Under intravenous administration, plasma levels of magnesium rose significantly. In the following weeks, the levels dropped in spite of continuing the therapy. The other parameters showed no important changes. Under i.v. administration of 40 mmol/day Mg-asp-HCl, the HPL increase was highly significant. If this could be taken as a hint of better placental function such a positive side effect of magnesium therapy could prove beneficial to "small-for-age" foetuses. Co-medication of 20 mmol/day Mg-asp-HCl (oral) or 40 mmol/day Mg-asp-HCl and MgSO4 (1:1, i.v.) is recommended.