Cardosi R J, Chez R A
Department of Obstetrics and Gynecology, University of South Florida, Tampa, USA.
Obstet Gynecol. 1998 Oct;92(4 Pt 2):691-3. doi: 10.1016/s0029-7844(98)00212-9.
Fetal bradycardia and decreased heart rate variability can indicate a nonreassuring fetal status. However, there can be iatrogenic, physiologic, or pathologic causes.
A patient in premature labor received toxic levels of magnesium sulfate for tocolysis. Elevated maternal serum magnesium levels correlated inversely with maternal temperature and both fetal heart rate and fetal heart rate variability. There was also a relative decrease of the maternal heart rate from baseline. When the magnesium levels returned to normal, these vital signs returned to normal.
Magnesium sulfate therapy can result in maternal hypothermia and a decrease in fetal heart rate and heart rate variability. Maternal hypothermia might be the cause of fetal bradycardia. A direct action of magnesium on the fetal heart might be the cause of heart rate variability.
胎儿心动过缓和心率变异性降低可能提示胎儿状况不佳。然而，其原因可能是医源性、生理性或病理性的。
一名早产患者接受了过量硫酸镁进行保胎治疗。孕妇血清镁水平升高与孕妇体温、胎儿心率及胎儿心率变异性呈负相关。孕妇心率也较基线水平相对降低。当镁水平恢复正常时，这些生命体征也恢复正常。
硫酸镁治疗可导致孕妇体温过低以及胎儿心率和心率变异性降低。孕妇体温过低可能是胎儿心动过缓的原因。镁对胎儿心脏的直接作用可能是心率变异性降低的原因。
