The effect of maternal hypocalcemia on fetal heart rate baseline variability.

Marked decrease in fetal heart rate variability during labor was observed in a term fetus, borne by a mother with severe hypocalcemia due to idiopathic hypoparathyroidism and nutritional vitamin D deficiency. During the period of decreased baseline variability, fetal scalp pH was normal. A marked increase in fetal heart rate variability was observed within 5 minutes of intravenous administration of 1 gram calcium gluconate to the parturient. It seems that the recognition of the effect of maternal hypocalcemia on baseline fetal heart rate variability is important for accurate interpretation of fetal monitor tracing.