Plasma and erythrocyte magnesium changes following a glucose challenge during pregnancy

This study examined the effects of pregnancy and glucose loading on plasma and erythrocyte (RBC) magnesium (Mg) concentrations. In a completely randomized design with repeated measures, 15 nonpregnant, 15 early pregnant (13-17 weeks) and 15 late pregnant (28-34 weeks) women ingested 100 g glucose. Blood was collected at 0, 30, 60, 120 and 180 minutes to evaluate changes in Mg levels. Fasting plasma Mg concentrations decreased slightly but not significantly as gestational age of the groups increased. Fasting RBC Mg concentrations were significantly higher (p less than 0.05) in late pregnant women compared with early pregnant and nonpregnant women. Plasma Mg responses to a glucose challenge in nonpregnant women exhibited a curvilinear pattern whereas responses in pregnant women appeared unaffected by the glucose challenge. RBC Mg concentrations for nonpregnant and early pregnant women failed to respond to the glucose challenge whereas it decreased in a linear pattern during late pregnancy. The diabetogenic effect of late pregnancy appears to affect RBC Mg. This redistribution of Mg during late pregnancy could suggest a possible role for RBC as a Mg pool.