Consideration of Magnesium Deficiency in Perinatal Hormonal and Mineral Imbalances

Abstract

In view of the evidence that inadequate magnesium intake is common during pregnancy and that the plasma levels of magnesium tend to fall, especially during the first and third trimesters of pregnancy even when corrected for hemodilution, it is not surprising that neonatal magnesium deficiency can create problems. Until relatively recent years, however, measurement of magnesium levels in infants was rare. Cord blood analyses, done at intervals since 1923 (Table 3–1) showed wide ranges reported in individual studies, even when the quite reliable old precipitation methods or the more reliable modern procedures were employed. Since individual maternal status and infant status were not designated in most instances, these wide ranges are difficult to interpret. Low levels may have reflected maternal and fetal insufficiency; high levels may have reflected magnesium therapy for preeclampsia. Mean values are even more difficult to evaluate. Determination of serum or plasma magnesium levels of the infant at birth or within hours thereafter presents more problems. Intrauterine asphyxia, difficulties in delivery, or other causes of birth hypoxia or acidosis, and hyperosmolality can all contribute to elevations of serum magnesium levels as the cellular magnesium is released to the extracellular fluid, changes similar to those seen with surgical and other traumatic shock and hypoxic conditions. Such infants have been found to have a negative correlation between their serum magnesium levels and their Apgar scores (Engel and Elin, 1970; Jukarainen, 1974).