Handwerker S M, Altura B T, Royo B, Altura B M
Department of Obstetrics and Gynecology, Booth Memorial Medical Center, Flushing, New York.
Am J Perinatol. 1993 Sep;10(5):392-7. doi: 10.1055/s-2007-994770.
Using a novel ion-selective electrode for ionized Mg (IMg2+), we sought to: (1) determine levels and fractions of IMg2+ in umbilical vessels of normal pregnant women: (2) determine their relationships with ionized calcium (ICa2+) levels: (3) determine whether any demographic or clinical parameters affect these levels of divalent cations: and (4) compare levels of IMg2+, total Mg, percent IMg2+, and ICa2+ with sera of normal pregnant and nonpregnant women. We obtained umbilical arterial and venous serum from 38 normal subjects and venous samples from 26 normal pregnant women and 42 nonpregnant women. The mean umbilical venous IMg2+ level (0.51 +/- 0.01 mmol/liter) was significantly greater than the umbilical arterial level (0.48 +/- 0.01 mmol/liter, p < 0.05), and the latter was similar to maternal venous levels (0.48 +/- 0.01 mmol/liter). The maternal venous mean value is 20% less than that found (0.60 +/- 0.005 mmol/liter) in peripheral serum of nonpregnant women. The ionized fractions were significantly (p < 0.01) higher in the umbilical veins than umbilical arteries, and the percent IMg2+ fractions were similar in umbilical arteries and maternal venous blood. IMg2+ levels were lower in multiparous patients and those who received epidural analgesia and higher in patients who had operative vaginal delivery and in Asians. Ionized fractions of Mg in umbilical veins were higher in large for gestational age infants. Our findings provide evidence of a Mg deficiency in pregnancy and suggest that measurement of IMg2+ may have clinical value for diagnosis and therapy of such deficiency.(ABSTRACT TRUNCATED AT 250 WORDS)
我们使用一种新型的离子化镁（IMg2+）离子选择性电极，旨在：（1）测定正常孕妇脐血管中IMg2+的水平和比例；（2）确定其与离子化钙（ICa2+）水平的关系；（3）确定是否有任何人口统计学或临床参数影响这些二价阳离子的水平；（4）比较正常孕妇和非孕妇血清中IMg2+、总镁、IMg2+百分比和ICa2+的水平。我们从38名正常受试者中获取了脐动脉和静脉血清，以及26名正常孕妇和42名非孕妇的静脉样本。脐静脉IMg2+的平均水平（0.51±0.01 mmol/升）显著高于脐动脉水平（0.48±0.01 mmol/升，p<0.05），且后者与母体静脉水平（0.48±0.01 mmol/升）相似。母体静脉平均值比非孕妇外周血清中发现的值（0.60±0.005 mmol/升）低20%。脐静脉中的离子化比例显著高于脐动脉（p<0.01），IMg2+百分比在脐动脉和母体静脉血中相似。经产妇和接受硬膜外镇痛的患者IMg2+水平较低，而接受阴道助产的患者和亚洲患者的IMg2+水平较高。巨大儿脐静脉中镁的离子化比例较高。我们的研究结果提供了孕期镁缺乏的证据，并表明测定IMg2+可能对这种缺乏的诊断和治疗具有临床价值。（摘要截断于250字）
