What are normal results for a magnesium measurement in pregnant women in preterm labor?

Magnesium level: Magnesium levels are normally between 1.7 and 2.2 mg/dl. Magnesium levels for therapy are between 4.0 and 6.0 mg/dl.

<8.4 mg/dL.: Serum magnesium concentration is not a clinically useful test, as physical findings/symptoms are more important than the serum value. In general, when tested, magnesium concentration should be <8.4 mg/dl to avoid toxicity.