Erythrocyte and plasma magnesium during teenage pregnancy: relationship with blood pressure and pregnancy-induced hypertension.

A prospective study of 53 nulliparous teenagers was conducted to determine differences in erythrocyte and plasma magnesium concentrations between subjects who had normal full-term deliveries (normal pregnant group) and those who developed pregnancy-induced hypertension. Magnesium content of monthly blood samples was determined by atomic absorption spectrophotometry. Socioeconomic data and information on use of supplements, medicines, tobacco, and alcohol were obtained by interview and medical chart review. Erythrocyte magnesium levels in both groups remained stable during pregnancy, whereas plasma magnesium showed a slight decline (P less than .08). Plasma and erythrocyte magnesium did not differ significantly between the normal pregnant (N = 30) and pregnancy-induced hypertension (N = 12) groups. Overall, mean arterial pressure was not significantly related to plasma or erythrocyte magnesium values. Within the pregnancy-induced hypertension group, there was a slight (P less than .05) inverse relationship between mean arterial pressure and plasma magnesium. The two groups were similar for socioeconomic characteristics, gynecologic age, previous use of oral contraceptives, and use of tobacco and magnesium-containing supplements. Pregnancy-induced hypertension subjects reported more alcohol use than did normal pregnant subjects (P less than .02). In conclusion, there was no evidence of magnesium depletion among teens who developed pregnancy-induced hypertension, by measurement of erythrocyte or plasma magnesium.